A440 Piano Tuner
Tune a piano to standard A440 with A4 at 440 Hz and browser microphone pitch detection.
A440 Piano Tuner Quick Reference
- Reference pitch
- A4 = 440 Hz
- Standard
- Modern concert pitch
- Temperament
- Equal temperament
- Best for
- Modern pianos and ensembles
- Tuner mode
- Browser microphone
About Standard A440 Tuning
A440 is the modern international standard for musical pitch, defining the note A above middle C as exactly 440 Hz. It was formally adopted by the International Organization for Standardization in 1955 as ISO 16, though it had been gaining acceptance since a 1939 international conference in London endorsed it. Before A440, pitch standards varied wildly between cities, orchestras, and instrument makers, creating chaos whenever musicians from different regions tried to perform together.
The path to A440 was shaped by decades of pitch inflation. Throughout the 19th century, orchestras and instrument makers kept raising the standard pitch to achieve a brighter, more brilliant sound. By the 1850s, some orchestras were tuning as high as A450 or beyond, straining singers and causing instruments to crack under the increased tension. A440 emerged as a practical compromise: high enough to retain brilliance, but not so high as to damage voices or instruments.
Today, A440 is virtually universal. Every electronic tuner, tuning app, and digital instrument defaults to this standard. Piano technicians worldwide tune to A440 unless specifically requested otherwise. While some orchestras in continental Europe tune slightly higher (A441-A443), and historically informed ensembles often tune lower, A440 remains the reference point against which all other pitch standards are measured.
Reference Notes
Temperament
Modern pianos are tuned in 12-tone equal temperament (12-TET), where the octave is divided into 12 equally spaced semitones. Each semitone is exactly 100 cents, and the frequency ratio between adjacent semitones is the twelfth root of 2 (approximately 1.05946). This system allows music to be played in any key with equal consonance, which is why it became the dominant tuning system for keyboard instruments from the late 18th century onward.
Tuning Tips for Standard A440
- 1.Always tune the A4 key first and verify it against a reliable reference tone at exactly 440 Hz. This is your anchor note from which all other pitches are derived.
- 2.When setting the temperament octave (typically F3 to F4), tune each interval by listening for the correct beat rate. In equal temperament, all major thirds beat faster as you ascend, and all perfect fifths beat slightly flat compared to pure intervals.
- 3.After setting the temperament octave, tune outward in both directions using octaves. Octaves should be beatless or nearly so, though slight stretching is normal on pianos due to string inharmonicity.
- 4.Perform at least two full passes across the keyboard. The first pass sets the overall pitch, but changing the tension on one string affects neighboring strings through the soundboard and bridge. A second pass corrects these shifts.
- 5.Check your work by playing major and minor triads in several keys. In equal temperament, every key should sound equally usable, with no key sounding noticeably more or less in tune than any other.
Best For
Contemporary repertoire
All modern classical, jazz, pop, and film music is composed and performed at A440. This is the pitch standard assumed by every modern score and recording.
Ensemble playing
When accompanying other modern instruments, A440 ensures everyone is on the same page. Wind instruments, electronic keyboards, and most string players all default to this standard.
Recording and production
Studios, DAWs, and virtual instruments all reference A440. Tuning your piano to this standard ensures it blends seamlessly with electronic and sampled sounds.
Teaching and examinations
Music schools, conservatories, and examination boards worldwide assume A440. Students preparing for graded exams or auditions should always practice on a piano tuned to this standard.
A440 Piano Tuner FAQ
What is Standard A440 piano tuning?
A440 is the modern international standard for musical pitch, defining the note A above middle C as exactly 440 Hz. It was formally adopted by the International Organization for Standardization in 1955 as ISO 16, though it had been gaining acceptance since a 1939 international conference in London endorsed it. Before A440, pitch standards varied wildly between cities, orchestras, and instrument makers, creating chaos whenever musicians from different regions tried to perform together.
How do I tune my piano to Standard A440?
Always tune the A4 key first and verify it against a reliable reference tone at exactly 440 Hz. This is your anchor note from which all other pitches are derived. When setting the temperament octave (typically F3 to F4), tune each interval by listening for the correct beat rate. In equal temperament, all major thirds beat faster as you ascend, and all perfect fifths beat slightly flat compared to pure intervals. After setting the temperament octave, tune outward in both directions using octaves. Octaves should be beatless or nearly so, though slight stretching is normal on pianos due to string inharmonicity. Perform at least two full passes across the keyboard. The first pass sets the overall pitch, but changing the tension on one string affects neighboring strings through the soundboard and bridge. A second pass corrects these shifts. Check your work by playing major and minor triads in several keys. In equal temperament, every key should sound equally usable, with no key sounding noticeably more or less in tune than any other.
What temperament is used for Standard A440?
Equal temperament. Modern pianos are tuned in 12-tone equal temperament (12-TET), where the octave is divided into 12 equally spaced semitones. Each semitone is exactly 100 cents, and the frequency ratio between adjacent semitones is the twelfth root of 2 (approximately 1.05946). This system allows music to be played in any key with equal consonance, which is why it became the dominant tuning system for keyboard instruments from the late 18th century onward.
What is A440 piano tuning?
A440 piano tuning sets the A above middle C, also called A4, to exactly 440 Hz. It is the modern standard pitch for pianos, orchestras, and digital instruments.
Can I tune a piano to A440 online?
Yes. Select Standard A440, allow microphone access, and play one note at a time. The tuner compares each detected piano note against the A440 equal-temperament target.