Metric

Tap tempo, BPM tables, note frequency, transpose, FM & LFO calculators, and 32 harmonics. Every timing and frequency answer a producer needs, offline and instant.

Metric is a pocket timing and frequency toolkit for iPhone and iPad. Whether you're setting delay times in a mix, tuning an FM patch, syncing an LFO, or transposing a sample, Metric gives you instant, precise answers, all in one distraction-free app.

TAP TEMPO Tap anywhere on the large touch target to measure tempo. See instant BPM from your last tap and a rolling average over up to eight taps. Send either reading straight into the BPM Converter, Transpose, or LFO Rate tools with a single tap. Your tempo flows across every tool automatically.

BPM → ms / Hz CONVERTER Enter a tempo and read straight, dotted, and triplet values for whole, half, quarter, eighth, and sixteenth notes. Every row shows milliseconds and frequency in Hz, so you can dial in delay, reverb pre-delay, or sidechain timing without reaching for a calculator.

TRANSPOSE & SPEED Pick an original key and a target key to see the semitone shift, interval name, and exact DAW transpose value. Add an original BPM and Metric computes the new tempo and playback speed ratio. Fine-tune with a cents slider (±100) and a speed slider spanning two full octaves (±24 semitones).

NOTE FREQUENCY TABLE Browse all 108 chromatic notes from C0 to B8. Each note shows its MIDI number, frequency in Hz, period in milliseconds, and sample counts at both 44.1 kHz and 48 kHz. Middle C is flagged for quick reference. Configurable A4 tuning (default 440 Hz) recalculates every value instantly.

FM CALCULATOR Two modes in one tool. Ratio Explorer lets you set carrier and modulator ratios with a base frequency and choose from ten classic FM presets, from hollow octaves (1:1) to inharmonic bells (1:π). Pitch Correction mode works in reverse: pick a target note and get the exact carrier and modulator frequencies. Both modes show a sideband table with up to ten partials, their frequencies, nearest notes, and colour-coded amplitudes driven by a modulation index slider.

LFO RATE CALCULATOR Convert any BPM into LFO rates across 17 musical divisions, from four bars down to 1/32 triplets. Each row displays Hz, period in milliseconds, and samples per cycle at 44.1 kHz and 48 kHz. Reverse lookup lets you enter any Hz value and find the closest matching musical division, with the error clearly shown.

HARMONIC SERIES EXPLORER Start from a frequency or pick any note and see the first 32 harmonics listed with frequency, nearest note name, cents deviation, and interval label. Low-order harmonics are colour-coded for easy identification. Deviations greater than 30 cents are highlighted so you can spot inharmonic content at a glance.

TOOLS THAT TALK TO EACH OTHER Tap a tempo once and it appears everywhere: BPM Converter, Transpose, and LFO Rate all share the same live BPM. Change your A4 tuning reference and it updates across Note Frequency, FM Calculator, and Harmonics simultaneously.

DESIGNED FOR PRODUCERS • Dark-mode aware interface • Adaptive layouts for iPhone and iPad • Two industry-standard sample rates: 44.1 kHz and 48 kHz

Whether you're a producer programming delays, a sound designer sculpting FM timbres, a synth player tuning oscillators, or an audio engineer checking frequencies, Metric puts every timing and frequency answer in your pocket. Fast, precise, and always within reach.