Rhythm Calculator Open app

A note from the developer

Why I Built Rhythm Calculator

Suzukake
Guitar cases lined up in the great hall where the band's summer camp was held.

I built Rhythm Calculator because I could see a rhythm on the page without being able to make it sound in my head. I knew what the notes and rests meant. The hard part was knowing exactly when each sound should happen on my bass.

The app did not start as a plan to build a music product. It started as a workaround I wanted during a short, crowded band camp.

The B Section I Could Not Hear Yet

I was playing electric bass at a three-night, four-day camp with my university light-music club. We had to learn a song quickly, and one particular B section kept catching me out.

The notes were in front of me. I could count the beats. But the rests, offbeats, and short spaces between sounds were not becoming something my fingers could trust.

My MIDI Workaround

Before this app existed, I used MIDI software and changed every pitch to C. I did not want to hear the melody. I only wanted to know when the sounds happened.

That worked, but it was heavy for a rehearsal. Entering a phrase that lasted about 30 seconds could take 10 to 20 minutes. I had to start the computer, choose the note lengths, add placeholder pitches, and check the result. There was not even a good desk near the music stand.

A MIDI editor showing every note placed on the C3 pitch line to check the rhythm.
My old workaround: put every pitch on C so I could listen for timing only.

I did not need the pitches. I needed to know when the sound happened.

— Suzukake

A Calculator for Note Values

That sentence shaped the interface. I wanted to enter note values as quickly as entering numbers into a calculator, then press Play and hear the rhythm immediately.

The screen shows the rhythm in notation-style form, but the input stays focused on timing. You can enter a short passage, listen, slow it down, and loop it while your instrument stays in your hands.

Rhythm Calculator's note input screen for entering and hearing a rhythm.
The calculator-style input keeps the focus on note values and timing.

What I Hope It Helps You Do

Rhythm Calculator is for the moment when you search “how do I count this rhythm?” but already have a specific song or score in front of you. I want the path from page to performance to feel less abstract:

  1. Look at the difficult measure.
  2. Enter only the rhythm you need.
  3. Hear it, sing it, tap it, and slow it down.
  4. Match your fingers to the timing.
  5. Turn the guide off and play the music yourself.

That is the whole idea. It is not a notation editor, a DAW, or a rhythm game. It is a small practice tool for the passage that is keeping you in one place.

For the complete workflow, read What Is a Rhythm Calculator?.