Pitch / Frequency Calculator
Free pitch and frequency calculator. Convert musical note names (A4, C5) to Hertz and back. Adjustable A4 reference pitch (440 Hz, 415 Hz, 432 Hz), MIDI numbers, and cents offset. Equal temperament tuning.
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What is Pitch / Frequency Calculator?
The Pitch Frequency Calculator is a free online tool that converts between musical note names (such as A4, C5, or F#2), MIDI note numbers, and audio frequencies in Hertz. It uses the 12-tone equal temperament (12-TET) system, the standard tuning for modern Western music, and lets you set the reference pitch (A4) to any value such as 440 Hz concert pitch, 415 Hz for baroque performance, 432 Hz, or a custom frequency. Enter a note name to instantly see its frequency and MIDI number, or enter a frequency in Hz to find the nearest note with its cents offset. A live reference table shows the frequency and MIDI number of every note in the selected octave. All calculations run entirely in your browser with no data uploaded, making it ideal for instrument tuning, audio engineering, music production, synth programming, and music theory study.
Key Benefits
- Instant bidirectional conversion between note names, MIDI numbers, and Hertz
- Adjustable A4 reference pitch supports concert, baroque, and alternate tunings
- Cents offset display tells you exactly how in-tune any frequency is
- Live octave reference table with copy-to-clipboard for every frequency
- 100% client-side — works offline, no sign-up, and your input never leaves your device
Common Use Cases
- •Instrument tuning: look up the target frequency for any note at any reference pitch
- •Audio engineering: identify the musical note of a recorded frequency or test tone
- •Music production: find MIDI note numbers for sampler and synthesizer programming
- •Music education: explore how equal temperament maps notes to frequencies
- •Historical performance: tune to 415 Hz baroque pitch or other period references
How to Use the Pitch Frequency Calculator
- Pick a note and octave: In the "Note to Frequency" section, select the note name (C to B) and the octave (0-8) you want to convert.
- Set the reference pitch (optional): Adjust the A4 reference pitch if you need a non-standard tuning such as 415 Hz baroque or 432 Hz. The default is 440 Hz concert pitch.
- Read the frequency: The frequency in Hertz and MIDI number for your note appear instantly. Click Copy to copy the Hz value.
- Reverse lookup (Hz to note): Enter any frequency in the "Frequency to Note" field to find the nearest note, MIDI number, and cents offset automatically.
Key Features
- Convert any note name (C0-B8) to its exact frequency in Hertz using 12-TET equal temperament.
- Reverse lookup: enter any frequency in Hz to find the nearest note, MIDI number, and cents offset.
- Adjustable reference pitch (A4) supports 440 Hz concert, 415 Hz baroque, 432 Hz, and custom tunings.
- Live reference table lists the frequency and MIDI number of every note in the selected octave.
- One-click copy of any frequency value, with MIDI numbers for DAW and synth workflows.