Online Harp Tuner: The Complete Guide
A harp can have anywhere from around 22 strings on a small lever harp to 47 on a full concert pedal harp, and unlike a guitar or ukulele, there's no small fixed set of "strings" to tune — every note across a wide range needs checking. This tuner is built for exactly that: real-time chromatic pitch detection across the harp's full range, with a tuning key selector that marks which notes belong to your instrument's diatonic scale.
How does this harp tuner work?
This tuner uses the Web Audio API built into modern browsers to capture a short sample of sound from your microphone, then runs it through an autocorrelation algorithm. Autocorrelation compares a sound wave against slightly delayed copies of itself to find the point where the pattern repeats — that repeat rate is the fundamental frequency of the string being played. Because a harp's range spans several octaves, this tuner reports both the note name and its octave, and compares the note to the nearest standard equal-tempered pitch to calculate how many cents sharp or flat it is.
How to Tune a Harp Online, Step by Step
- Set your tuning key from the chips above the note grid — this determines which notes are marked as belonging to your harp's diatonic scale.
- Find a quiet space. A harp's open, ringing strings make background noise and the ring of neighboring strings more noticeable to a pitch detector than a fretted or damped instrument.
- Tap "Start Tuner" and allow microphone access when your browser asks. This permission is required for any pitch-detection tuner to hear your strings.
- Pluck one string at a time close to where you'd normally play, letting it ring rather than muting it immediately.
- Watch the note name, octave, and needle. The highlighted key on the note grid shows exactly which of the 12 notes you're closest to.
- Adjust the tuning pin slowly until the reading shows "in tune" and the needle centers, then move to the next string.
Lever Harps vs. Pedal Harps: Different Tuning Conventions
How a harp is tuned depends heavily on which type it is:
- Lever (folk) harps are usually strung diatonically in a single key, most commonly C major or E-flat major, with small levers on each string that can raise its pitch by one semitone when engaged.
- Pedal (concert) harps are strung so their resting position sounds C-flat major. Each of the seven pedals has three positions — flat, natural, and sharp — so starting from flat lets a pedal raise that string's pitch by one or two semitones as a piece requires, covering every key from a single stringing.
The tuning key selector on this tool is most directly useful for lever harps, where it marks every note belonging to your harp's home scale. For pedal harps, set the key to C-flat (displayed here as B, its enharmonic equivalent) to match the instrument's true resting tuning, and rely on the chromatic detection itself — which works identically regardless of key — for pedal-raised notes.
Why the Tuning Key Matters
Marking which notes are diatonic to your selected key helps distinguish a genuinely mistuned string from a note that's simply not part of your harp's home scale to begin with — useful context on an instrument with dozens of strings, where it's easy to lose track of which pitch a given string is supposed to be. The chromatic detection engine itself checks every string against the same standard pitch reference no matter which key is selected; the key selector only changes which notes are visually marked, not how any individual note is measured.
Common Harp Tuning Problems (and How to Fix Them)
The tuner won't detect any sound
This almost always comes down to one of three things: microphone permission was denied, the page isn't loaded over a secure (https) connection, or your input volume is too low. Check your browser's site settings to confirm microphone access is allowed, and make sure no other tab or app is already using the microphone.
Neighboring strings are confusing the reading
A harp's open strings resonate easily, and a nearby string can ring sympathetically when you pluck the one you're tuning. Lightly damping the strings on either side of the one you're working on usually clears this up.
Strings won't hold their tuning
New strings, particularly gut or nylon strings common on many harps, stretch significantly during their first period of use and will drift repeatedly until they settle — this is normal. Harps are also notably sensitive to humidity and temperature changes given the number of strings under tension, so tuning may shift noticeably between rooms or seasons even on a well-settled instrument.
Frequently Asked Questions
Is this online harp tuner free to use?
Yes. This harp tuner is completely free, runs in your browser, and does not require an account, download, or app install.
What key are harps normally tuned to?
Lever and folk harps are commonly tuned diatonically to a single key, most often C major or E-flat major. Concert pedal harps are strung to sound C-flat major at rest, since each pedal's flat position becomes the baseline that natural and sharp positions are raised from.
Why does a pedal harp tune to C-flat major instead of C major?
Each of a pedal harp's seven pedals has three positions: flat, natural, and sharp. Stringing the harp so its resting position is C-flat major means every pedal starts in the flat position, leaving natural and sharp available to raise that string by one or two semitones as a piece requires.
Why won't my harp tuner detect sound?
Most commonly this happens because microphone permission was denied, the page is loaded over an insecure http connection instead of https, or background noise or the ring of neighboring strings is making it hard for the pitch detector to lock onto a single string.
Pitch detection runs entirely on your device — audio from your microphone is never recorded, stored, or sent to a server.