Free, no-sign-up calculators and reference tools for music producers, recording and mixing engineers, and DJs. Everything runs instantly in your browser — nothing to install, nothing to log in for. Bookmark this page and come back whenever you need a quick answer.
Tempo & Timing
Delay Time Calculator
Turn any BPM into note-perfect delay times in milliseconds.
Reverb Pre-Delay & Decay
Match reverb pre-delay and decay to your track’s tempo.
Tap Tempo / BPM Counter
Tap along to find the BPM of any song by ear.
Online Metronome
Free click track with adjustable tempo, beats and accents.
Song Length Calculator
Work out track duration from bars, BPM and time signature.
Genre BPM Chart
Typical tempo ranges for every major genre, at a glance.
Key, Pitch & Harmony
Note ↔ Frequency
Convert any note to its frequency in Hz — and back.
Scale & Chord Finder
Find the notes in any scale and the chords that fit.
Circle of Fifths
Interactive reference for keys, sharps, flats and relatives.
Camelot Wheel
Pick harmonically-compatible keys for DJ mixing.
Chord Transpose & Capo
Transpose chords to a new key or find the right capo fret.
Mixing, EQ & Acoustics
EQ Frequency Cheat Sheet
What every frequency band does, instrument by instrument.
Room Mode Calculator
Find problem resonances from your room dimensions.
SPL Distance Calculator
How loudness drops with distance (inverse-square law).
Decibel (dB) Calculator
Add, subtract and convert dB, gain and amplitude ratios.
Frequency ↔ Wavelength
Convert frequency to wavelength for treatment and miking.
Loudness & Delivery
LUFS Loudness Targets
Target loudness for Spotify, YouTube, Apple Music and more.
Audio File Size Calculator
Estimate file size from sample rate, bit depth and length.
Frequently asked questions
Are these tools really free?
Yes. All 18 calculators are completely free, with no sign-up, no watermark and no usage limits. They run entirely in your browser, so your inputs never leave your device.
Do I need to install anything?
No. Everything works in any modern browser on desktop or mobile — just open a tool and start typing. Nothing to download or configure.
Which calculator should I start with?
The Delay Time Calculator and Tap Tempo are the most-used. If you mix or master, jump to the LUFS Loudness Targets and EQ Cheat Sheet.