Concert Pitch and Frequency Conversion: A Complete Guide for Musicians

The Berlin Philharmonic tunes to A=443 Hz. The New York Philharmonic tunes to A=442 Hz. The Vienna Philharmonic also uses 443 Hz. Historically informed Baroque ensembles perform at A=415 Hz, a full semitone below the modern standard. Meanwhile, ISO 16:1975, the international standard ratified in London in 1939 and confirmed by the International Organization for Standardization in 1975, defines A4 as exactly 440 Hz. If you are working with recordings, backing tracks, or playback audio that needs to match a specific ensemble or historical tuning, you cannot simply nudge the pitch by ear. You need the math, and you need a tool that applies it correctly.

This converter lets you set any reference pitch from 380 Hz to 500 Hz and apply it to your audio file. The conversion uses the Web Audio API's playback rate to shift every frequency in your recording by the exact ratio. The result is downloadable as a 16-bit PCM WAV file. Everything runs locally in your browser. Your audio never leaves your device.

What Is Concert Pitch?

Concert pitch is the agreed reference frequency for the note A above middle C, known as A4 in scientific pitch notation. All other notes in equal temperament are derived from A4 using the formula:

f = A4 x 2^((n - 69) / 12)

Here, n is the MIDI note number, where A4 = 69. Every semitone is a ratio of 2^(1/12), approximately 1.05946. When the reference frequency changes from 440 Hz to 442 Hz, every note in the scale shifts upward by the same ratio (442/440 = 1.004545), which corresponds to approximately 7.85 cents. At 443 Hz, the shift is about 11.76 cents above 440 Hz. At 415 Hz, the shift is roughly -81.5 cents below 440 Hz, almost exactly one semitone flat.

This matters for practical reasons beyond orchestras. If you record a guitar tuned to 440 Hz and then want to sync it with a string ensemble tuning to 442 Hz, every instrument in your session will sound slightly flat against the strings. A frequency converter applies the correct ratio to pull the recording up to match.

Common Concert Pitch Standards

The table below shows the most common reference frequencies, their deviation from A=440 in cents, and typical usage. One cent is 1/100 of a semitone. Human pitch discrimination is generally around 5 to 10 cents depending on the listener and context, which means deviations of 7 to 12 cents are sometimes noticeable and always measurable.

415 Hz (Baroque): Used by historically informed performance (HIP) ensembles performing Baroque and early Classical repertoire. The deviation from 440 Hz is approximately -81.5 cents, close to one semitone flat. This pitch derives from historical organ and harpsichord tuning in 17th and 18th century Europe. If you are using a modern instrument to double a Baroque recording, you often need to drop nearly a semitone.
432 Hz (Alternative standard): This tuning sits 31.77 cents below A=440. It is associated with Verdi's tuning preference and with communities that argue for a warmer or more natural sound. The scientific evidence for any physiological benefit over 440 Hz is not established, but the demand for conversion tools is high, particularly among ambient, folk, and meditative music producers. Use our 432 Hz Converter if you only need this specific conversion.
440 Hz (ISO standard): The international standard per ISO 16:1975. Used by most recorded music, DAW default tuning, and the majority of instrument manufacturers worldwide. If your audio is already at 440 Hz and you select 440 Hz as the target, no processing occurs.
442 Hz (European orchestras): Common in German, French, and many other European orchestral contexts. The deviation is +7.85 cents above 440 Hz. The New York Philharmonic and many US chamber ensembles also use this pitch.
443 Hz (Berlin, Vienna): Used by the Berlin Philharmonic and the Vienna Philharmonic. The deviation is +11.76 cents above 440 Hz. This is the most common high-pitch standard among top-tier orchestras in 2024 and 2025.
444 Hz: Used by some French and Italian orchestras and in certain solo piano contexts. The deviation is +15.64 cents above 440 Hz.
446 Hz: A high tuning standard sometimes used in brass-heavy ensembles and solo contexts. The deviation is +23.35 cents above 440 Hz.

How the Frequency Conversion Works

The math behind concert pitch conversion is straightforward. Given a source reference frequency (typically 440 Hz) and a target reference frequency, the conversion ratio is:

ratio = target Hz / source Hz

For a conversion from 440 Hz to 442 Hz, the ratio is 442/440 = 1.004545. For a conversion from 440 Hz to 432 Hz, the ratio is 432/440 = 0.98182. This ratio is applied to the playback rate of the audio. Playing audio at 1.004545x speed shifts every frequency in the recording up by that ratio, including the fundamental pitch, all harmonics, and all overtones. The relationship between the ratio and cents is:

cents = 1200 x log2(ratio)

And the relationship between the ratio and semitones is:

semitones = 12 x log2(ratio)

One side effect of changing the playback rate is that the duration of the audio changes. Playing at a ratio of 1.004545 means the audio plays 0.45% faster. A four-minute track at 440 Hz will be approximately 3 minutes 58.9 seconds when converted to 442 Hz. At 432 Hz, the same track extends to about 4 minutes 4.4 seconds. The converter displays the new duration before you download, so you can account for this difference in your project.

The live preview in this tool uses real-time playback rate adjustment via the Web Audio API. The download uses an OfflineAudioContext, which renders the audio at the exact ratio into a clean buffer and encodes it as a 16-bit PCM WAV file. The download is not subject to any streaming artifacts or latency from real-time processing.

Why Musicians Change Concert Pitch

The most common use cases for frequency conversion fall into three categories.

Matching historical recordings or instruments. If you are overdubbing onto a Baroque performance recorded at 415 Hz, your modern instrument tuned to 440 Hz will sound sharp by almost a semitone. You can either retune the instrument (which is not always practical for keyboard instruments, fretted strings, or wind instruments with fixed bore dimensions), or convert the backing track up to 440 Hz for recording and then convert your overdub back down to 415 Hz. This tool handles either direction.

Matching an ensemble's live tuning standard. Session musicians working with orchestras tuned to 442 Hz or 443 Hz need backing tracks, click tracks, and reference recordings at the same pitch. A track produced at 440 Hz in a DAW will be approximately 8 to 12 cents flat against a 442/443 Hz ensemble. Converting the track up to the ensemble's pitch before the session prevents that conflict.

Producing at a specific reference pitch by preference. Some producers and composers work at 432 Hz or 444 Hz as a deliberate aesthetic choice. If your DAW is set to 440 Hz and you receive stems from a collaborator at 440 Hz, this converter lets you shift them to your working reference. You can also use our Pitch Shifter for larger pitch adjustments or our Frequency Calculator to look up exact note-to-frequency relationships at any reference pitch.

Live Preview vs. Offline Rendering

The A/B toggle in this tool lets you switch between the original audio and the converted audio during playback. The preview is implemented using an AudioBufferSourceNode with its playback rate set to the conversion ratio. This gives you instant feedback when you adjust the target frequency, without waiting for a full offline render.

The download button triggers an offline render using OfflineAudioContext. The offline context processes the entire buffer at the specified ratio and encodes the result as a WAV file. The output duration reflects the ratio change: a ratio below 1.0 produces a longer file (lower target pitch), and a ratio above 1.0 produces a shorter file (higher target pitch). There is no pitch artifact from the offline render because the entire buffer is processed in a single pass at a fixed rate.

If you need to convert audio by a larger interval without the duration change that comes with playback-rate shifting, the Pitch Shifter uses phase vocoder processing for duration-preserving transposition. For small concert pitch adjustments (under 50 cents), the duration change is minimal and the playback rate method produces a cleaner result.

Using This Tool in Practice

Upload your audio file using the file picker or by dragging it onto the upload area. The tool accepts WAV, MP3, OGG, FLAC, and AAC formats. Select your target frequency using the number input, the slider, or one of the quick preset buttons. The info panel updates in real time to show you the conversion ratio, the cents shift, the semitone equivalent, and the new duration.

Press Play to hear the converted audio. Use the A/B toggle to compare it against the original. When you are satisfied, press Download WAV to save the processed file. The downloaded filename includes the target frequency so you can keep track of multiple conversions from the same source file.

For tuning accuracy verification after conversion, use our Online Tuner to confirm that your converted track's reference pitch matches your target. Load the tuner in a separate tab, play the converted WAV, and check that the A note reads at your target frequency.

Custom Frequency Converter