A piano is a keyboard instrument that makes sound when its keys are pressed. Pressing a key activates a system that causes felt-covered wooden hammers to strike strings inside the piano. Most modern pianos have 88 black and white keys, except for the Bosendörfer and Stuart & Sons models, which are tuned to all the notes in order using equal temperament. A person who plays the piano is called a pianist.

There are two main types of piano: the grand piano and the upright piano. Grand pianos produce better sound and allow for more precise control of the keys. They are often chosen when space and money allow, and they are commonly used in places where skilled pianists perform. Upright pianos are smaller and less expensive, making them more widely used in homes and schools.

When a key is pressed, hammers strike the strings. The vibrations travel through a bridge to a soundboard, which helps the sound travel through the air. When the key is released, a damper stops the strings from vibrating, ending the sound. Most notes have three strings, while the lowest notes (bass) have one or two strings. Pedals at the bottom of the piano can be used to lift the dampers, allowing notes to continue ringing. The sustain pedal lets pianists layer sounds, creating richer and more expressive music.

In the 19th century, the fortepiano changed with the use of a cast iron frame, which allowed for stronger string tension. A technique called aliquot stringing gave grand pianos a louder, longer-lasting sound and a fuller tone. As pianos became more common, families could enjoy new music by having a family member play simpler versions of the pieces.

The piano is used in many types of music, including classical, jazz, traditional, and popular styles. It is used for solo performances, group music, accompaniment, and for writing and practicing music. Even though pianos are heavy and expensive, their versatility, the training of musicians, and their availability in schools, venues, and practice spaces have made them a common instrument in Western cultures.

History

The piano was developed from earlier inventions in instruments that use strings struck by hammers and keyboard mechanisms. The earliest known keyboard instrument was the Ancient Greek hydraulis, a type of pipe organ created in the third century BC. Pipe organs remained in use in Europe during the Middle Ages, helping builders learn how to make keyboard mechanisms that could produce musical notes. The first string instruments with struck strings were hammered dulcimers, which came from the Middle East and were brought to Europe during the Middle Ages. Many attempts were made in the Middle Ages to create stringed keyboard instruments with struck strings. By the 17th century, the mechanisms of keyboard instruments like the clavichord and harpsichord were well developed. In a clavichord, strings are struck by small metal pieces called tangents. In a harpsichord, strings are plucked by quills when a key is pressed. Over centuries, builders learned how to make the cases, soundboards, bridges, and mechanical parts of harpsichords, which helped later piano designs.

The word "piano" comes from the Italian "pianoforte," which means "soft and loud." This name describes how the piano can play notes at different volumes based on how hard a pianist presses the keys. When a key is pressed harder, the hammer inside hits the string with more force, making the sound louder. The fortepiano, invented in 1700, was the second keyboard instrument (after the clavichord) that allowed players to control volume and tone by pressing keys with different amounts of pressure. Unlike the pipe organ and harpsichord, the fortepiano could change its sound based on the player's touch.

The piano was invented by Bartolomeo Cristofori of Padua, Italy. He worked for Ferdinando de' Medici, the Grand Prince of Tuscany, as the Keeper of the Instruments. Cristofori was an expert in making harpsichords and knew a lot about keyboard mechanisms. He used this knowledge to create the first pianos. An inventory from the Medici family shows a piano existed by 1700. The three surviving Cristofori pianos date from the 1720s. Cristofori called his instrument "a keyboard of cypress with soft and loud," which was later shortened to "pianoforte," "fortepiano," and finally "piano."

Cristofori's greatest achievement was designing a keyboard instrument where hammers strike the strings. The hammers must hit the strings and then quickly move away to avoid stopping the strings from vibrating. They also must return to their resting position smoothly, so they do not accidentally play the same note again. This design allowed players to repeat notes quickly. Cristofori's piano action influenced many later piano designs.

Cristofori's early pianos used thin strings and were quieter than modern pianos. However, they were louder and had longer sound than clavichords, which could only produce soft sounds. The harpsichord could make loud sounds but could not change the volume of individual notes. The piano combined the best features of these earlier instruments, allowing both loud and soft playing.

Cristofori's invention was not widely known until 1711, when an Italian writer named Scipione Maffei wrote a detailed article about it. The article was translated into German and shared widely. Many future piano builders studied this article. One of them was Gottfried Silbermann, known for building organs. Silbermann created pianos similar to Cristofori's but added a pedal that lifted all the dampers from the strings, allowing notes to continue sounding after the keys were released. This pedal became the modern sustain pedal.

In the 1730s, Silbermann showed Johann Sebastian Bach one of his early pianos, but Bach disliked it because the high notes were too soft. Later, Bach approved of a newer piano and helped sell Silbermann's instruments. Bach used the phrase "piano et forte genandt" (meaning "soft and loud") to describe the instrument's ability to change volume.

During the late 18th century, the Viennese school of piano making became famous. Builders like Johann Andreas Stein, Nannette Streicher, and Anton Walter created pianos with wooden frames, two strings per note, and leather-covered hammers. Some of these pianos had the opposite color scheme of modern pianos, with black natural keys and white accidental keys. Wolfgang Amadeus Mozart composed music for these instruments, and replicas are still used today for authentic performances. These early pianos had a softer sound and less sustain than modern pianos.

Between 1790 and 1860, the piano underwent major changes, leading to the modern design. These changes were driven by the Industrial Revolution, which provided better materials like strong piano wire and iron frames that could handle the tension of strings. The range of the piano also expanded from five octaves to seven octaves or more.

In the late 18th century, the Broadwood firm made significant contributions to piano design. John Broadwood, along with partners, created the first "grand" piano by placing the instrument in a harpsichord case. Their pianos became known for their powerful sound and large size.

Types

Modern pianos come in two main types: grand pianos and upright pianos. Each type has many different styles. Other types include specialized pianos, electric pianos that use electromechanical parts, electronic pianos that create piano-like sounds with oscillators, and digital pianos that use recorded sounds of real piano notes.

In a grand piano, the frame and strings are arranged horizontally, with the strings extending away from the keyboard. The action, which is the system that makes the keys work, is located beneath the strings and uses gravity to return to its resting position. Grand pianos vary in length from about 1.5 to 3 meters (4 feet 11 inches to 9 feet 10 inches). Some lengths have traditional names, such as:

• Baby grand: around 1.5 meters (4 feet 11 inches)
• Parlor grand or boudoir grand: 1.7 to 2.2 meters (5 feet 7 inches to 7 feet 3 inches)
• Concert grand: 2.2 to 3 meters (7 feet 3 inches to 9 feet 10 inches)

Longer pianos with longer strings produce larger, richer sounds and have less inharmonicity. Inharmonicity is when the extra sounds from the piano strings are slightly out of tune compared to the main note. This happens because the strings are stiff. As a struck string vibrates, its extra sounds vibrate slightly from the ends toward the center of the string.

Inharmonicity can also come from imperfections in the strings, such as rust on plain strings or dirt in the windings of bass strings. The higher the extra sound, the more it is out of tune. Pianos with shorter and thicker strings, like small pianos, have more inharmonicity. More inharmonicity makes the tone sound harsher.

Because of inharmonicity, piano tuners must stretch octaves, or tune them slightly higher to match the piano's natural sound. If octaves are not stretched, single octaves may sound in tune, but double or triple octaves sound too narrow. Stretching the octaves on a small piano can cause other tuning problems.

In a concert grand, the octave stretch keeps the tuning balanced, even when aligning high notes to a sound from three octaves below. This helps octaves sound pure and creates nearly perfect fifths. This gives the concert grand a clear, singing tone, which is why full-size grand pianos are used in concert halls. Smaller grand pianos are better for home use and some small performance spaces.

Upright pianos, also called vertical pianos, have a vertical frame and strings. The upright piano's action was invented in London in 1826 by Robert Wornum. Upright pianos are more compact, making them better for home use. The hammers move horizontally and return to their resting position using springs, which can wear over time.

Some upright pianos with tall frames and long strings were called "upright grand," but this name is misleading. Modern pianos are sometimes classified by height and action modifications. Upright pianos are usually less expensive than grand pianos. They are widely used in churches, schools, and music programs as practice instruments.

• Spinets are very short, with the action below the keys, connected to the keys by vertical wires.
• Consoles are slightly taller than spinets and have a compact action with shorter hammers. They usually play better than spinets.
• Studio pianos are about 107 to 114 cm (42–45 inches) tall. This is the shortest height that can fit a full-sized action above the keyboard.
• Pianos taller than studio models are called uprights. Technically, any piano with a vertical soundboard could be called an upright, but the term is usually reserved for full-size models.

Toy pianos, introduced in the 19th century, use round metal rods instead of strings to make sound. The US Library of Congress recognizes toy pianos as a unique instrument with the subject code Toy Piano Scores: M175 T69.

In 1863, Henri Fourneaux invented the player piano, which plays itself using a piano roll. A machine records a performance on paper rolls, and the player piano replays it using air-powered devices. Modern versions, like the Bösendorfer CEUS, Yamaha Disklavier, and QRS Pianomation, use solenoids and MIDI technology instead of air and rolls.

A silent piano is an acoustic piano with a feature that stops the strings from making sound, using a hammer bar. This allows quiet practice without disturbing others.

In 1801, Edward Ryley invented the transposing piano, a rare instrument with a lever that moves the keyboard relative to the strings. This lets a pianist play in a familiar key while the music sounds in a different key.

The minipiano was patented in 1934 by the Brasted brothers. It has a braceless back and a soundboard below the keys. Metal rods pull on levers to make the hammers strike the strings. The first model, called the Pianette, had tuning pins that extended through the instrument, allowing it to be tuned from the front.

A prepared piano is a piano used in modern art music with objects placed inside it to change its sound. These objects, like rubber or metal, mute the strings or alter their tone. Scores for prepared piano music include instructions for the pianist to place these items inside the piano.

Some Viennese fortepianos had percussion effects activated by levers, used in pieces like Mozart's Rondo alla Turca.

A pedal piano is a rare type with a pedal keyboard at the base, played by the feet. The pedals may play the existing bass strings or have their own set of strings and hammers. Pedal pianos are often used to practice pipe organ music at home, though some musicians use them for performances

Construction and components

Pianos have more than 12,000 parts that support six main functions: the keyboard, the action (which includes hammers, hammer shanks, and whippens), dampers and their underlevers, bridges, the soundboard, and strings. Many parts are made from materials chosen for strength and long-lasting use. The outer rim, often made of hard maple or beech, is especially important. Its solid structure helps the soundboard vibrate freely, allowing sound to be produced clearly. Harold A. Conklin explained that a strong rim helps keep vibrational energy in the soundboard instead of letting it escape into other parts of the piano, which do not help sound travel well.

Hardwood rims are usually made by layering thin strips of wood, bending them into shape after glue is applied. This method was developed by C.F. Theodore Steinway in 1880 to save time and money during production. Before this, the rim was made from solid wood pieces joined together, a method used by European makers until the 20th century. Bösendorfer, an Austrian piano maker, uses solid spruce for its inner rims, the same wood used for the soundboard. Their design allows the rim to vibrate more freely with the soundboard, adding more depth and complexity to the sound.

The thick wooden posts on the underside (for grand pianos) or back (for uprights) help support the rim. These posts are made of softwood for stability. The need for strong, sturdy materials makes pianos heavy. A small upright piano can weigh 136 kg (300 lb), while the Steinway concert grand (Model D) weighs 480 kg (1,060 lb). The largest piano available, the Fazioli F308, weighs 570 kg (1,260 lb).

The pinblock, which holds the tuning pins, is made of hard maple or beech and is layered for strength. Piano strings, also called piano wire, are made of high carbon steel to handle years of tension and force. They are made as uniformly as possible to avoid sound distortion. Bass strings are wrapped with copper wire to add weight while keeping flexibility. If all strings were individual, the heavy bass strings would overpower the higher notes. To balance this, makers use two strings (bichords) for the tenor range and three strings (trichords) for the treble range.

The plate, or metal frame, of a piano is usually made of cast iron. A heavy plate helps transfer vibrations from the strings to the soundboard effectively. While some makers use cast steel, most prefer cast iron because it is easier to shape, more flexible, and better at resisting compression. Plate casting requires precise measurements, as cast iron shrinks slightly during cooling. To make the plate look better, makers polish, paint, or add decorative elements, such as the manufacturer's logo.

In the 1940s, Alcoa and Winter and Company tried using aluminum plates to make pianos lighter. However, aluminum plates were not widely accepted and were later stopped. Earlier, a nearly all-aluminum piano was placed on the airship Hindenburg.

Most parts of the piano action, such as hammers and levers, are made from hardwood like maple, beech, or hornbeam. Since World War II, some makers have also used plastics. Early plastics used in the 1940s and 1950s were not durable and lost strength over time. In 1961, Steinway used Teflon in some parts of its Permafree grand action instead of traditional wool cloth bushings. However, this was stopped in 1982 because Teflon caused problems with friction and looseness. More recently, Kawai used carbon fiber reinforced plastic for action parts, and Wessell, Nickel and Gross made composite parts. It remains to be seen if these materials last as long as wood.

In most pianos, the soundboard is made of spruce boards glued together along the side grain. Spruce is chosen because it is strong yet lightweight, helping sound travel efficiently. High-quality makers use spruce with tight grain patterns, carefully dried over time. Low-cost pianos often use plywood for the soundboard.

Piano hammers are designed to be soft enough to avoid creating overly loud, high-pitched sounds. They must be light enough to move quickly when keys are pressed but strong enough to strike strings forcefully when needed. Early piano keys were made from sugar pine, but modern keys are usually made from spruce or basswood. Spruce is used in high-quality pianos. Black keys were traditionally made of ebony, and white keys were covered with ivory. Today, ivory is rare and protected, so most makers use plastic. Yamaha developed a plastic called Ivorite to look and feel like ivory.

Most modern pianos have 52 white keys and 36 black keys, totaling 88 keys (seven octaves plus a minor third, from A0 to C8). Some older pianos have 85 keys (seven octaves from A0 to A7). Some manufacturers have added more keys. For example, the Imperial Bösendorfer has 97 keys, including nine extra bass keys. These extra keys are sometimes hidden under a lid or colored differently to avoid confusion. Recently, Stuart & Sons made a piano with 108 keys, covering nine full octaves from C0 to B8.

Mechanics

When a piano key is pressed, a series of events happens to create sound. First, the key lifts the "wippen" mechanism, which pushes the jack against the hammer roller (or knuckle). This action raises the lever that holds the hammer. At the same time, the key lifts the damper. When the hammer hits the string, it quickly moves away, letting the string vibrate and produce sound. When the key is released, the damper returns to the string, stopping the vibration and ending the sound.

The piano strings themselves do not make loud sounds, but their vibrations travel to a large soundboard. The soundboard moves air, turning the energy into sound. The bridge, which connects the strings to the soundboard, has an unusual shape and position. This design helps the soundboard vibrate strongly at all frequencies. The damper remains raised until the key or sustain pedal is released, allowing the note to continue.

Three factors affect the pitch of a vibrating string:
– Length: If all other parts are the same, a shorter string creates a higher pitch.
– Mass per unit length: If all other parts are the same, a thinner string creates a higher pitch.
– Tension: If all other parts are the same, a tighter string creates a higher pitch.

A vibrating string divides into parts that vibrate together. Each part creates its own pitch, called a partial. A string has one main pitch (the fundamental) and many other partials. The most harmonious sound happens when one pitch is exactly twice the frequency of another.

For a repeating wave, the velocity (v) equals the wavelength (λ) multiplied by the frequency (f):
v = λ × f

On a piano string, waves bounce off both ends. When these waves combine, they form a standing wave pattern. This happens only for specific wavelengths: λ = 2L, L, 2L/3, L/2, …, or λ = 2L/n, where L is the string’s length. This means only certain frequencies are produced: f = nv/2L. The quality of sound (timbre) depends on the mix of these harmonics. Different instruments have different harmonic patterns for the same pitch. Real strings vibrate at frequencies that are not perfect multiples of the fundamental. This slight mismatch, called inharmonicity, adds richness to the sound but makes tuning more difficult.

Hitting a piano key harder increases the wave’s amplitude, which increases the sound’s volume. When a key is struck very softly (pianissimo, pp), the hammer moves slowly and stays in contact with the string for about 4 milliseconds. When struck very loudly (fortissimo, ff), the hammer moves quickly and stays in contact for less than 2 milliseconds. If two strings tuned to the same pitch are struck at the same time, their vibrations combine to create a louder, shorter sound. If the vibrations are out of sync, they cancel each other, creating a softer, longer sound.

Maintenance

Pianos are heavy and strong, but they are also delicate. Over time, trained piano movers have created special methods to move both grand and upright pianos safely, protecting the case and the internal parts. Pianos need regular tuning to stay in the correct musical pitch. The hammers inside pianos are adjusted to account for the felt becoming harder over time, and other parts also need regular checks and adjustments. Pianos require consistent care to ensure the hammers and key mechanisms work properly. Older or worn-out pianos can be repaired or restored by piano rebuilders. Eventually, the strings must be replaced. By replacing many parts and adjusting them, old pianos can perform as well as new ones.

Piano tuning involves changing the tightness of the strings using a special tool, which helps the piano’s notes align correctly. While guitar and violin players usually tune their own instruments, pianists often hire a piano tuner, a trained technician, to adjust their pianos. Piano tuners use special tools. The term "in tune" for pianos does not mean the notes are set to a fixed set of pitches.

Fine piano tuning carefully examines how all the notes of the chromatic scale interact, which varies for each piano, and requires slight adjustments to the pitches. Pianos are usually tuned to an adjusted version of a system called equal temperament. In all tuning systems, each note’s pitch is based on its relationship to a chosen fixed pitch, typically the standard concert pitch of A4 (the A above middle C). The term A440 refers to the widely accepted frequency of this pitch: 440 Hz.

The relationship between two pitches is called an interval, and it is based on the ratio of their frequencies. Two intervals sound the same when their pitch ratios are equal. The simplest intervals to recognize and tune are those with whole-number ratios, called just intervals. The term "temperament" refers to a tuning system that slightly adjusts these just intervals (often the perfect fifth, with a ratio of 3:2) to meet another mathematical rule. In equal temperament, a fifth is slightly adjusted by lowering the higher note or raising the lower note. A temperament system is also called a set of "bearings."

Tempering an interval causes the notes to produce a wavering sound called beating, which happens because the pitches are close but not exactly the same. The speed of beating depends on the differences in frequencies of matching harmonics from both notes. Piano tuners use their ears to "stretch" the tuning of a piano, making it sound in tune. This involves tuning the highest notes slightly higher and the lowest notes slightly lower than a standard frequency chart would suggest.

Playing and technique

The piano can be played using written music, by listening and remembering, or by creating music on the spot. Some folk and blues pianists learned on their own, but in classical and jazz music, there are organized teaching methods and institutions. These include exams for students before college, university degrees, and advanced diplomas such as the B.Mus., M.Mus., and Doctor of Musical Arts in piano. Piano techniques changed as the instrument evolved from the harpsichord and clavichord to the fortepiano and then to the modern piano. Changes in music styles and audience tastes during the 19th and 20th centuries, along with the rise of highly skilled performers, influenced these changes. Many teachers and musicians emphasize that piano playing involves both physical skills and mental or emotional aspects. Famous techniques include those developed by Dorothy Taubman, Edna Golandsky, Fred Karpoff, Charles-Louis Hanon, and Otto Ortmann.

Many classical composers, such as Haydn, Mozart, Schubert, and Beethoven, wrote music for the fortepiano, which was different from today’s piano. Even Romantic-era composers like Franz Liszt, Frédéric Chopin, Clara and Robert Schumann, Fanny and Felix Mendelssohn, and Johannes Brahms composed for pianos that were not like modern instruments. Today’s musicians may adjust how they play older music to match the sound and style of historical instruments.

During Beethoven’s later years, the fortepiano became more like the modern piano. By the late 19th century, modern pianos were widely used. These had more keys than the fortepiano, adding about 30 keys to expand the range of low and high notes. Mass production made upright pianos affordable for middle-class families. They were played in music halls and pubs, often by soloists or with small dance bands. Similar to how harpsichordists accompanied singers and dancers, pianists took on this role in the late 18th and 19th centuries.

In the 19th century, American musicians, especially African-American composers, created new music styles using the modern piano. Ragtime, popularized by Scott Joplin, became widely known by 1900. Ragtime was later replaced by Jazz piano. New techniques, such as ostinato for boogie-woogie and Shearing voicing, were developed. George Gershwin’s Rhapsody in Blue combined jazz piano with symphonic music.

A technique called comping, used to accompany jazz vocalists, was demonstrated by Duke Ellington. Honky-tonk music, with a different rhythm style, became popular around the same time. Bebop techniques emerged from jazz, led by pianists like Thelonious Monk and Bud Powell. In the late 20th century, Bill Evans blended classical methods with jazz. In the 1970s, Herbie Hancock became popular by mixing jazz with urban music styles like jazz-funk and jazz-rock.

Pianos are also central to rock and roll and rock music, used by artists such as Jerry Lee Lewis, Little Richard, Keith Emerson, Elton John, Ben Folds, Billy Joel, Nicky Hopkins, Rick Wakeman, Freddie Mercury, and Tori Amos. In 2023, Freddie Mercury’s Yamaha baby grand piano, used to compose Bohemian Rhapsody, sold for £1.7 million, a record for a composer’s piano. Modernist composers like John Cage and Philip Glass have also written for the modern grand piano.

The piano was introduced to Burma in the mid-19th century and adapted by court musicians. A unique technique called “interlocked fingering” allows both hands to play a single melody with added notes, inspired by traditional Burmese rhythms. Many Burmese pianists, such as Sandayar Hla Htut and Sandayar Chit Swe, use the Burmese word sandaya (စန္ဒရား) as part of their titles.

Role

The piano is an important instrument in many types of Western music. It is used for playing melodies alone, supporting other instruments, or helping musicians practice together. Pianos can be played by one person, with a singer or another instrument, in small groups like bands or chamber ensembles, or in large groups such as orchestras. Many composers and songwriters know how to play the piano because the keyboard allows them to test different melodies and harmonies, and to try playing several musical lines at the same time. Pianos are also used by composers who write music for movies and television because the wide range of notes helps them create melodies and bass lines, even if the final music will be played by other instruments.

Bandleaders and choir conductors often learn to play the piano because it helps them learn new songs and lead performances. Many conductors are trained in piano playing because it allows them to practice parts of the music they are conducting, using a shorter version of the score. This helps them understand how to interpret the music. The piano is a key tool in music education at schools, colleges, and universities. Most music classrooms and practice rooms have a piano. Pianos are used to teach music theory, music history, and music appreciation. Even music teachers who do not play the piano may have one in their office.