Why do Pianos go out of tune?

Pianos are one of the most popular musical instruments in the world and for good reason.  People are drawn to the rich, acoustic sound and often want to own a real one instead of a digital reproduction. 

However, it can be disappointing when sitting down to play, only to realize the piano has gone out of tune, and there are a variety of reasons why this can happen.

In this article, I will be going over the main reasons that a piano can go out of tune, how to know when it needs to be tuned, and what alternatives there are to pianos that don’t need any tuning.

Why do Pianos go out of tune?

Changes in temperature and humidity cause expansions or contractions of the soundboard, resulting in unwanted changes to the pitch of the strings. Similarly, haphazard moving of the piano can unbalance string tension. On top of this, general playing and lack of maintenance of the complex system of pins, bridges and strings will cause instability in tuning over time.

There’s a lot more that goes into it, but that’s the basic gist of it.

Now, let’s dive in a little deeper and find out exactly why and how pianos goes out of tune.

Temperature and humidity fluctuations (Keep it in a stable environment)

Many people believe that pianos go out tune due to being played, however this is not usually the main reason.

Pianos consist of hammers, strings and a soundboard. The strings are stretched to a high tension equaling a pressure around 38,000 pounds. It is the role of the soundboard to support those strings and provide a resonate surface, which vibrates when the hammers strike the strings.

The soundboard has a “curve” which means it rises near the center.

With environmental changes, such as changes in temperature and humidity, the soundboard warps, expanding or contracting in the process.

This effects the tension of the strings, which over time can change the pitch of the notes. 

With the natural wood used in pianos, a rise in humidity can cause the board to absorb moisture, expanding the wood and tightening the strings, while in the drier months, wood shrinks slightly, creating the opposite effect.

When humidity goes up, the pitch will go sharp, and a shift of humidity downward causes the pitch to go flat.

To avoid the worst effects of this process, you can think about where to place your piano. The most beneficial environment for your piano is a humidity ranging between 45% and 70% and a temperature of around 20˚C. 

However, I have found that this level of detail isn’t always possible, so I always try to consider other practical aspects of piano placement, as a way of minimizing exposure to environmental fluctuations.

The best way to do this is to simply choose a dry room with a moderate temperature and avoid positioning your piano next to open windows, radiators and direct sunlight.

Moving the Piano

Another common cause of unwanted changes in pitch are due to haphazard moving of the piano.  Although your piano may be your pride and joy (like it is mine!), some delivery companies don’t always treat it this way. 

If a piano is jostled around during delivery, it may create a misbalance in the tension of the strings leading to tuning problems. One way around this, is to use dedicated delivery companies who specialize in delivery of pianos or delicate musical instruments. These companies use highly-trained technicians who take the utmost care and consideration when moving these delicate instruments. 

Additionally, as a rule of thumb you should wait around 3 weeks after moving your piano into a new environment before having it tuned, since this will allow it to settle and adjust to the new conditions and avoid the need for another expensive retune.

Overall build– and material quality

An often-overlooked factor when considering a piano’s resilience to tuning problems, is the overall build quality of the piano itself: More expensive pianos with better quality parts will tend to retain tuning more effectively than those with poorer quality components.

Higher quality wood may not be quite as susceptible to the effects of temperature and humidity changes. 

Additionally, lower quality pianos are not constructed with the same attention to detail as handmade pianos. Unfortunately, this often results in persistent tuning issues. 

So, it may be worth considering saving up for an extra few months and shopping around for a well-cared for, good quality instrument.

Poor maintenance

Another factor to consider is the general maintenance of the piano; Old pianos or those in need of repair are far more likely to slip out of tune than newer or well-maintained pianos.

The strings of a piano are held in place by tuning pins and these ‘tuning pins’ are held by a thread inside the ‘tuning pin block’ (this is made of various density wood laminations, such as maple, hornbeam and beech). This delicate part of the piano can rupture due to the tension of the piano strings over time.

Additionally environmental pressures can result in a loss of friction, leading to the piano not being able to stay tuned. 

The bridge is a portion of the piano that attaches the strings to the soundboard, and these are sometimes cracked and need replacing. Often the bridges can split along the line of the bridge pins; as the strings are tightened during tuning. The pins then move and do not keep the piano wire in place.

Additionally, V-bars, agraffes, and hitch pins can bend or move as well. All of these complex parts need maintenance, often requiring a skilled expert and carpenter who know how to select the correct materials for the piano.

A less complex explanation for loss of tuning is simply the action of the piano being played. 

Forceful playing and regular usage will cause wear and tear and changes in string tension. This, combined with a gradual unwinding of the string as time passes will cause the tuning to gradually slip, despite best efforts to avoid it. 

This is a natural part of owning a piano!

How do you know when your piano needs to be tuned?

The best way to determine if your piano needs tuning is to listen. Often you will sit down at your piano after a number of months of owning it and realize that is doesn’t sound quite right.  It probably needs tuning at this point.

Unlike violins and guitars, the tuning process is extremely complex and takes skilled technicians with years of experience.  This is really a case where you should trust the professionals! 

Indeed, it is recommended that pianos are tuned every 6 months; since any less can result in general instability and conditioning problems.  

Tuning is carried out using a variety of tools such as tuning levers, wedges and tuning forks. Levers are used to alter the note whilst other notes are muted.  It’s a slow and delicate process.

Generally speaking, even old pianos can be tuned as long as all the components are in place. If constant tuning is becoming expensive, you may want to consider a digital piano. I myself own a digital piano and they are useful for their mobility, ease of use and lack of need for tuning.

However, although many sound surprisingly realistic, for me when it comes to sound, there’s nothing like the real thing!

I also wrote an article comparing digital pianos to keyboards, how they differ from each other as well as from acoustic pianos, their pros & cons, and more.


In conclusion, there are many factors which cause a piano to become out of tune; the main being environmental factors such as temperature and humidity fluctuations, transportation of the piano, build quality as well as general wear and tear caused by frequent playing and the passage of time.

Overall, you can avoid the need for constant tuning by placing the piano in moderate environment away from sunlight, as well as investing in a good quality instrument which will hold its tuning more effectively.

Even so, the piano should still be maintained and tuned by a skilled professional at least 1 – 2 times every year.

Happy Playing!