Why Do Pianos Have 88 Keys? (And Why Some Don’t)

You may have observed that nearly every piano you've seen has 88 keys, and judging from your visit to this page, you've wondered why that is.

Why do pianos have 88 keys? A piano has 88 keys for both historical and practical reasons. Over the centuries, the key range of the piano continued to increase to keep up with musicians' more intricate and challenging pieces. After Steinway manufactured its 88 key piano in the late 1880s, 88 keys became the global standard.

In this article, we'll discuss why there are 88 keys on a piano, why there aren't more than 88 keys on a piano, and why some pianos may even have less than 88 keys.

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Why Are There 88 Keys On A Piano?

To understand why pianos have 88 keys, one must examine the historical factors that have contributed to this development. Pianos throughout history have never had 88 keys; in fact, they had much fewer keys than what we typically see today.

We can trace the history of the piano back to the harpsichord, its predecessor. The harpsichord was the instrument of choice for many composers, which had a total of 60 keys.

This scope of keys available at the time meant that compositions written for harpsichords were confined to a range of five octaves.

At the beginning of the eighteenth century, Bartolomeo Cristofori invented the first piano by replacing the plucking mechanisms with hammers to give musicians greater control over their volume dynamic.

This piano was similar in appearance to the harpsichord and consisted of hammers and dampers with a total of 54 keys. Word of this invention spread, and it gradually grew in popularity and, with it, a community of composers.

Eventually, the piano became widely used by influential composers such as Mozart and Haydn during the classical period. However, due to the range of 54 keys being too limiting, manufacturers expanded the compass of the keyboard.

This expansion resulted from composers' requests to achieve a broader range of musical expressions.

By the middle of the nineteenth century, pianos were equipped with seven octaves, a sum of 85 keys, allowing composers such as Chopin and Liszt to compose works that explored a more extensive range.

Then, in the late 1880s, Steinway created the 88-key piano. After that, other manufacturers began to produce pianos with the same key range, resulting in the 88-key piano becoming a global standard.

As a result, practically all modern pianos (upright, grand and otherwise) will have a standard of 88 keys. If you happen to see an acoustic piano with fewer keys 88 keys, it likely dates back to before 1890. However, this does not mean that all modern-day pianos subscribe to this standard.

Related article: What Are The Differences Between An Upright And A Grand Piano?

There are a few exceptions, such as Bösendorfer, which sells 97-key pianos, and Stuart and Sons, who subsequently set a world record in 2018 for creating a nine-octave piano with a total of 108 keys.

Both Steinway and Bösendorfer are featured in My New Microphone's Top 11 Best Acoustic Piano Brands In The World.

However, as mentioned before, manufacturers often limit the key range of their pianos up to 88 keys. So, to conclude, today's contemporary piano is the result of both historical and practical influences.

Why Don’t Pianos Have More Than 88 Keys?

As mentioned previously, some pianos have more than 88 keys, although this is not considered the standard practice. This standard is due to the sound frequencies the pianos produce.

The human ear can only hear from 20Hz – 20,000Hz. That is, of course, if your hearing is exceptionally sensitive. 20 Hz is universally accepted as the lowest frequency that a human ear can detect (though we feel these bass frequencies more than we hear them), while the highest is 20,000 Hz (which barely anyone past the age of 5 can hear with any accuracy).

The lowest key of the piano, referred to as A2, emits a frequency of 27.5 Hz. As such, adding more notes to the bass end of the piano will not prove beneficial since the human ear will not be able to comprehend it fully. The fundamental frequency begins to get lost, and while our ears can “fill in the fundamental” by processing the overtones, the low notes aren't overly musical anyway.

These lower-end notes, if added, will be perceived more like a rumbling noise rather than a comprehensible musical note. The harmony of bass tones is typically restricted to octaves and sometimes fourths and fifths since more colourful harmonic structures in the low end tend to become muddy and ill-defined with all the rumble and dissonance between the overtones.

That being said, the extra bass notes in pianos such as the 97-note Bösendorfer piano are used to add harmonic resonances that contribute to the overall sound of the piano.

Furthermore, the highest note on a standard 88-key piano, C5, emits a frequency of 4,186 Hz.

Although this frequency falls within the normal range of human hearing, the problem lies in how pleasant and discernable the human ear perceives these higher frequencies.

At around 4,000Hz, the human ear can no longer make sense of these frequencies, resulting in an unpleasant dissonant sound rather than a recognizable musical note.

It is the overtone profiles that largely make up these frequencies rather than the fundamentals. Playing notes this high up also leads to ambiguity as the ear tries its best to discern the pitches being played.

Thus, adding extra notes to the treble end of the piano would be impractical from a musical standpoint.

Related article: Fundamental Frequencies Of Musical Notes In A=432 & A=440 Hz

Why Do Some Pianos Have Less Than 88 Keys?

As previously stated, if you come across a piano with less than 88 keys, it was most likely manufactured before 1890. Moreover, if you do happen to come across a ‘modern piano' with fewer than 88 keys, it will most likely be a digital piano.

Manufacturers of digital pianos consider the target market and affordability of the instrument, which can result in fewer keys being included. Digital pianos with fewer keys often cost less than their fuller key-range counterparts.

In addition, having fewer keys makes the digital piano more portable. The portability of a piano can be an excellent fit for gigging musicians and laypeople alike.

Digital pianos, which often have a 76 key range, are more than suitable for pianists who only play specific genres, such as contemporary pop, or are in a beginner-intermediate stage of their piano playing.

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The expansion of the key range was needed in order for composers to express their materials fully. As a result, the number of keys added to the piano substantially grew until the late nineteenth century, when a standard of 88 keys was adopted.

The piano does not have any more keys because the human ear can not fully comprehend much higher or lower than the notes already available on the piano. As a result, the piano is equipped with a full range of notes that are pleasant to the human ear.

This article has been approved in accordance with the My New Microphone Editorial Policy.


Arthur is the owner of Fox Media Tech and the author of My New Microphone. He's an audio engineer by trade and works on contract in his home country of Canada. When not blogging on MNM, he's likely hiking outdoors and blogging at Hikers' Movement (hikersmovement.com) or producing music. For more info, please check out his YouTube channel and his music.

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