Metric iOS

A pocket timing and frequency toolkit for iPhone and iPad, now with a built-in metronome. Whether you're keeping time, 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. Now with Siri, Shortcuts, widgets, and a Live Activity.

Metronome with tap tempo & visual beats
BPM → ms / Hz converter (straight, dotted, triplet)
Note ↔ Frequency table (108 notes, tuning-aware)
Transpose & Speed, FM Calculator, LFO Rates, 32 Harmonics
Siri, Shortcuts & a Home/Lock Screen BPM widget

Screenshots

Includes light and dark screenshots that follow the website theme.

Tap and measure tempo. Instant and averaged BPM with one touch.

Tap Tempo screen on iPhone — Tap and measure tempo. Instant and averaged BPM with one touch.

Save and recall tempo presets. Keep your favourite BPMs one tap away.

Tap Tempo preset screen on iPhone — Save and recall tempo presets. Keep your favourite BPMs one tap away.

Convert BPM to ms and Hz. Straight, dotted, and triplet values at a glance.

BPM to ms/Hz table on iPad — Convert BPM to ms and Hz. Straight, dotted, and triplet values at a glance.

Look up any note's frequency. 108 notes with Hz, MIDI, period, and sample counts.

Note to frequency screen on iPhone — Look up any note's frequency. 108 notes with Hz, MIDI, period, and sample counts.

Transpose keys and speed. Semitone shift, interval name, and new tempo instantly.

Transpose and Speed screen on iPhone — Transpose keys and speed. Semitone shift, interval name, and new tempo instantly.

Your pocket producer toolkit. Tap tempo, BPM tables, FM, LFO, and more.

Tap Tempo with sidebar on iPad in portrait — Your pocket producer toolkit. Tap tempo, BPM tables, FM, LFO, and more.

Design FM timbres by the numbers. Ratios, sidebands, and pitch correction in one view.

FM calculator screen on iPhone — Design FM timbres by the numbers. Ratios, sidebands, and pitch correction in one view.

Sync your LFO to the beat. 17 divisions from 4 bars to 1/32 triplets.

LFO rate screen on iPad — Sync your LFO to the beat. 17 divisions from 4 bars to 1/32 triplets.

Explore the harmonic series. 32 harmonics with frequencies, notes, and intervals.

Harmonic series screen on iPhone — Explore the harmonic series. 32 harmonics with frequencies, notes, and intervals.

Keep perfect time. A precise metronome with visual beats and background-safe timing.

Metronome running on iPhone — Keep perfect time. A precise metronome with visual beats and background-safe timing.

Control it from anywhere. Home & Lock Screen widgets, Siri, Shortcuts, and Dynamic Island.

Widgets, Siri, and Shortcuts on iPad — Control it from anywhere. Home & Lock Screen widgets, Siri, Shortcuts, and Dynamic Island.

Features

Metronome: A precise metronome with a large tempo dial, tap-to-set tempo, adjustable time signatures and subdivisions, and a clear visual beat indicator. Background-safe timing keeps the click steady even with the screen locked.
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.
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 44.1 kHz, 48 kHz, and 96 kHz. Middle C is flagged for quick reference. Based on A4 = 440 Hz.
FM Calculator: Ratio Explorer lets you set carrier and modulator ratios with a base frequency and choose from ten classic FM presets. 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, 48 kHz, and 96 kHz. Reverse lookup lets you enter any Hz value and find the closest matching musical division.
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.

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. Note Frequency, FM Calculator, and Harmonics all stay consistent at A4 = 440 Hz.

Siri, Shortcuts & Widgets

Drive Metric hands-free. Ask Siri to start or stop the metronome, set a BPM, tap a tempo, convert BPM to milliseconds, find a note frequency, or transpose a tempo. Every tool is a Shortcuts action too, and the BPM widget keeps your tempo on the Home and Lock Screen, with a Live Activity and Dynamic Island while the metronome runs.

Designed for Producers

Runs entirely offline no account, no ads, no tracking
Dark-mode aware interface
Adaptive layouts for iPhone and iPad
Three industry-standard sample rates: 44.1 kHz, 48 kHz, and 96 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.