DelayCalc BPM: Delay & Reverb
LFO, loop length, key & pitch
$2.99
Type one tempo. Get every note value in ms and Hz, whether the reverb tail clears the next hit, loop lengths in odd meters, and the key after a tempo change. Offline.
Type one tempo and every time-based value for that song comes out at once.
Delay times, LFO rates, reverb tails, loop lengths in odd meters, the key after a tempo change, and sample counts. No reopening a second calculator.
Dark enough to read in a studio, and every value copies with a tap.
■ Delay & LFO
Enter a BPM and every note value lines up with its delay time in ms and its LFO rate in Hz. Straight, dotted and triplet, plus 5- and 7-tuplets (5:4 / 7:4). Tap a note value for seconds and sample counts at 44.1 / 48 / 96 kHz.
It goes the other way too. Enter the ms or Hz you already have and get the BPM back, with the closest note values listed — so "what tempo is this pedal's 375 ms" takes one entry.
■ Reverb
Pre-Delay and Total Reverb Time from the tempo, with Decay and where the tail lands.
Then Tail Clearance: whether the tail ends before the next hit, and by how much. Clear, overlapping, or exactly on it — as a number rather than a guess.
The basis is stated on screen: Total Reverb Time includes Pre-Delay, quarter-note basis. Plugins define Reverb Time differently, and that is on screen too.
■ Tempo & Key
From a sample's original and target tempo: Tempo Change, Playback Speed, Semitones and Cents.
Then the key it lands on, in Camelot Key and Open Key, with the Harmonic Matches worth mixing into. Preserve Key (Master Tempo / Key Lock) treats the key as unchanged.
Enter the original duration and you also get the new length, its sample count, and how it fits into bars.
■ Loop Length
Bar and loop lengths from a time signature (3/4, 5/4, 5/8, 6/8, 7/8, 9/8 and more) in ms, seconds, Hz and sample count.
Or the other way: give it a length and get the tempo.
■ Library
Keep the setups you use, named, up to 50. Restoring brings back the page and the time signature, so you carry on where you were.
■ Where it earns its place
· Setting delay and LFO values in a DAW
· Keeping a reverb tail off the next hit
· Matching a delay pedal or hardware synth to the tempo by hand
· Getting the BPM and note value back from ms or Hz you already have
· Loop lengths in odd meters, and sequencer rates
· The key a sample lands on after a tempo change
· Lining effects up to tempo at a rehearsal or a live set
■ What it does and does not do
· Values use the project tempo, quarter-note based, so they match your DAW
· Reverb and delay tails are starting points. Set the final value by ear, to suit the source and the gear
· No microphone analysis, no DAW integration. You type, it answers
■ Quietly dependable
· Saved setups stay on the device. Nothing is sent to a cloud
· The core calculation works offline. Only the privacy policy opens a connection
· No account
· No ads
· No subscription. One purchase
· iPhone, iPad and Mac on that one purchase
■ Note values
1/1, 1/2, 1/2D, 1/4, 1/4T, 1/4D, 1/8, 1/8T, 1/8D, 1/16, 1/16T, 1/16D, 1/32, 1/32T, 1/32D
Advanced: 1/4 (5:4), 1/8 (5:4), 1/16 (5:4), 1/4 (7:4), 1/8 (7:4), 1/16 (7:4)
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Version 2.0.0 — a lot more of the song's timing, from the same one tempo
■ Reverb (new)
Pre-Delay and Total Reverb Time from the tempo, plus Tail Clearance: whether the tail ends before the next hit, as a number. A starting point for keeping the next hit clean.
■ Tempo & Key (new)
Playback speed, semitones and cents when a sample changes tempo — and the key it lands on, in Camelot Key with its Harmonic Matches. New duration, sample count and bar fit as well.
■ Loop Length (extended)
Bar and loop lengths in odd meters, and now the tempo derived from a known length.
■ Library (extended)
Name what you keep, up to 50 setups. Restoring brings back the page and the time signature too.
■ Japanese localisation
Units, note values and industry terms stay as the studio writes them; the prose is translated.
■ iPhone, iPad and Mac
One purchase covers all three.
■ Also
Four areas instead of one long screen, resume on the tempo and page you left, haptics on each Tap Tempo strike, and a lot of smaller display and interaction fixes.
Offline, no account, no ads and one purchase — unchanged.
The developer, KENTA OSAWA, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- KENTA OSAWA
- Size
- 18.5 MB
- Category
- Music
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPad
Requires iPadOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 11.0 or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 K's App
