Music Theory Tools
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Rhythm Pattern Maker

Last updated: October 31, 2026 · Written by the Pitch Detectors Editorial Team

16-step sequencer with swing, BPM, multiple instruments, step preview, randomize, export/import. Uses Tone.js for accurate timing.
120 BPM
0%
Tip: click a step to toggle it (preview sound plays). Use Randomize to generate patterns. Export/Import uses JSON.

What Is a Rhythm Pattern Maker?

A rhythm pattern maker is an online step sequencer that lets you program drum grooves by toggling steps on a grid. Each column is a slice of musical time and each row is a drum sound; the pattern loops continuously. This free tool gives you a 16-step grid (expandable to 32 or 64), tempo and swing controls, classic drum kits, and one-click export.

The step sequencer is one of the oldest ideas in electronic music: divide a bar into equal steps, decide which steps trigger a sound, and loop it. This tool brings that workflow to your browser with sample-accurate timing.

Key Takeaways

  • A 16-step grid = one bar of 16th notes in 4/4 time; steps 1, 5, 9, and 13 are the quarter-note downbeats.
  • Each step's length in milliseconds is 15,000 ÷ BPM — at 120 BPM every step lasts exactly 125 ms.
  • Swing delays the off-beat steps; 54–62% gives the classic MPC hip-hop groove, 66.7% equals a triplet shuffle.
  • Start from genre blueprints (four-on-the-floor, boom-bap, tresillo) instead of an empty grid.
  • Export your pattern as JSON and rebuild it in any DAW in under a minute.

How This Rhythm Pattern Maker Works

This tool schedules every drum hit on the Tone.js Transport clock, wired directly to the Web Audio API's hardware clock. Standard browser timers like setTimeout drift under CPU load; the Transport clock pre-schedules each hit against audio-hardware timestamps, so a 120 BPM loop stays locked to the grid.

Methodology: each active cell maps to a sixteenth-note subdivision of the pattern length. Tempo (40–240 BPM) sets the pulse; Division re-maps the grid to quarter, eighth, sixteenth, or triplet-sixteenth notes; Swing (0–60%) delays even-numbered steps. Two kits are built in — Classic and 505. Last reviewed: October 2026.

Step Timing Math and Worked Example

Every step sequencer runs on one formula. In 4/4 time, one bar holds 4 quarter-note beats, and each beat divides into 4 sixteenth notes — 16 steps per bar. The time each step occupies is:

Step duration (ms) = 15,000 ÷ BPM

(Because one quarter note lasts 60,000 ÷ BPM milliseconds, and a sixteenth note is one quarter of that.) Here is what that means at common tempos:

Tempo Typical genre One step lasts One bar lasts
92 BPM Boom-bap hip-hop 163.0 ms 2.61 s
120 BPM Pop / funk 125.0 ms 2.00 s
128 BPM House 117.2 ms 1.88 s
140 BPM Trap (half-time feel) 107.1 ms 1.71 s
174 BPM Drum and bass 86.2 ms 1.38 s

Worked example: at 128 BPM, one step = 15,000 ÷ 128 = 117.2 ms. A four-on-the-floor kick on steps 1, 5, 9, and 13 lands every 4 × 117.2 = 468.8 ms — exactly one quarter-note apart.

How to Use This Rhythm Pattern Maker

  1. Set the BPM: drag the tempo slider (40–240). Start near your genre's home tempo — 90–95 for boom-bap, 124–128 for house, 140 for trap. Tap along with our BPM tap tempo tool if you're matching an existing track.
  2. Choose the pattern length: 16 steps = 1 bar, 32 = 2 bars, 64 = 4 bars. Use 16 for sketching, 32–64 when your fill needs room to breathe.
  3. Pick a division: 1/16 for standard programming, 1/8 for half-time feels, Triplet 16 for shuffles and trap rolls.
  4. Select a drum kit: Classic for warm analog-style tones, 505 for punchy digital drums.
  5. Program the grid: click cells to toggle hits — click and drag to paint runs. Clicking a step previews its sound immediately.
  6. Dial in swing: raise the Swing slider from 0% toward 55–60% for hip-hop bounce, or leave it at 0% for rigid techno quantization.
  7. Play, randomize, export: hit Play to loop the pattern, Randomize for algorithmic inspiration, Clear to start over, and Export JSON to save your work.

Reading Your Pattern: Where the Beats Fall

On a 16-step grid in 4/4, not all steps are equal. Steps 1, 5, 9, and 13 are the quarter-note downbeats — the pulse you nod your head to. Steps 3, 7, 11, and 15 are the "ands" between beats, where off-beat hi-hats live. Everything else is sixteenth-note detail.

Steps Musical position Typical role
1, 5, 9, 13 Quarter-note downbeats Kick drum foundation
5, 13 Beats 2 and 4 Snare / clap backbeat
3, 7, 11, 15 Off-beats ("ands") Open hats, syncopation
2, 4, 6, 8, 10, 12, 14, 16 Sixteenth subdivisions Hi-hat drive, ghost notes, rolls
TEMPO & BEAT GRID Alt text: "Anatomy of a 16-step drum sequencer grid in 4/4 time" BEAT 1 BEAT 2 BEAT 3 BEAT 4 BAR 2 ¼ NOTE ¼ NOTE annotated 16-step grid showing downbeats on steps 1/5/9/13, backbeat on 5/13, and off-beat hi-h
Alt text: "Anatomy of a 16-step drum sequencer grid in 4/4 time"

Genre Groove Blueprints: Copy These Step Patterns

Start from a genre's rhythmic DNA, then change 2–3 steps to make it yours:

  • House / Techno (124–128 BPM): kick on 1, 5, 9, 13 (four-on-the-floor); clap on 5, 13; open hats on 3, 7, 11, 15; closed hats on every even step.
  • Boom-bap hip-hop (90–94 BPM): kick on 1, 7, 10; snare on 5, 13; hats on every step with swing at 56–58%. The lazy kick placement behind the grid is the whole sound.
  • Trap (140 BPM, half-time feel): kick on 1, 8, 11; snare on 9 only (the "third-beat" snap); rapid hat rolls on 14–16 using the Triplet 16 division.
  • Dembow / Reggaeton (~100 BPM): kick on 1, 4, 7, 10, 13; snare on the tresillo accents — steps 4, 7, and 12. That 3+3+2 kick skeleton is non-negotiable.
  • Drum and bass (172–176 BPM): kick on 1, 11; snare on 5, 13; two-step hats shuffling on the off-beats. Speed does the work — keep the pattern sparse.

Swing Percentage Translated to Milliseconds

Swing delays every even-numbered step by a fraction of the step duration. The offset formula is:

Swing offset (ms) = (Swing% ÷ 100) × Step duration (ms)

Worked example: at 120 BPM with 58% swing, one step lasts 125 ms. Each off-beat step shifts later by 0.58 × 125 = 72.5 ms. That 72 ms delay is the difference between a robotic grid and a head-nodding groove — long enough to feel, short enough to stay locked.

Reference points: 0% is machine-straight; 54–62% is the classic MPC hip-hop pocket; 66.7% equals a true triplet shuffle (2:1 ratio).

From Browser to DAW: The Export Workflow

The Export JSON button downloads your entire session — grid triggers, BPM, swing, kit, and pattern length — as a small text file. The JSON maps each drum voice to an array of active step numbers, for example {"kick": [1, 5, 9, 13], "bpm": 128}. To continue in a DAW:

  1. Export the JSON and open it in any text editor to see your step numbers.
  2. In your DAW's drum sequencer (Ableton Drum Rack, FL Studio Channel Rack, or Logic's Step Sequencer), set the same BPM and step count.
  3. Enable the matching step numbers for each drum voice — the numbers transfer 1:1.
  4. Re-apply swing in the DAW (most offer a groove/swing knob) using the percentage you dialed in here.

Keep the JSON files as versioned sketches (chorus-v1.json, chorus-v2.json) — they weigh kilobytes, and Import JSON reloads any of them for quick auditioning.

Choosing a Pattern Length for Song Sections

Pattern length is an arrangement decision, not just a bigger grid. 16 steps (1 bar) is for sketching and for sections that must feel hypnotic — techno intros, trap verses. 32 steps (2 bars) lets you write call-and-response: keep bar one simple, add a fill or variation in bar two. 64 steps (4 bars) fits a full phrase with an intro, build, and turnaround — ideal for choruses and drops.

A practical workflow: sketch the verse at 16 steps, expand to 32 for the pre-chorus with one added fill, and open the full 64 for the chorus. For bar-to-time conversions at your tempo, use the BPM to milliseconds calculator.

Polyrhythm vs. Polymeter: Stop Mixing Them Up

A polyrhythm layers two subdivisions over the same timespan — 3 evenly spaced hits in the time of 2 beats (the 3:2 hemiola). A polymeter layers two different bar lengths sharing the same step duration — a 4-step loop against a 5-step loop, realigning every 20 steps (their lowest common multiple).

On this grid, accent steps 1, 6, and 11 against straight quarter-note kicks for a 3-against-4 polyrhythm. For a polymeter, loop a 12-step phrase inside the 16-step grid by muting one voice's last 4 steps and let the downbeat drift.

[Infographic: swing timing diagram — straight 16ths vs 58% swing vs triplet shuffle, with millisecond offsets at 120 BPM]
Alt text: "How swing percentage shifts off-beat steps in milliseconds"

Limitations

  • Browser audio latency varies. The Transport clock keeps timing tight, but Bluetooth headphones and heavy system load can add 20–100 ms of output delay. Use wired headphones for critical groove work.
  • Export is JSON, not audio. This tool saves patterns, not rendered WAV files — you rebuild the sound in a DAW or re-record the browser output.
  • No per-step velocity (yet). Every hit plays at full volume, so ghost notes and accents must be programmed with density rather than dynamics.
  • Fixed 4/4 framework. Odd meters like 7/8 or 5/4 can't be represented on the 16-step grid; approximate them with muted steps or use a DAW.
  • Two kits only. The Classic and 505 kits cover a lot of ground, but they won't replace a full sample library for acoustic genres.

Rhythm Pattern Maker vs. Alternatives

Approach Best for Trade-off
This step sequencer Fast groove sketching, learning rhythm theory 16-step grid, two kits, JSON export only
DAW piano roll (Ableton, FL Studio) Full productions, velocity, automation Paid software, steeper learning curve
Drum pads / finger drumming Human feel, live performance Requires practice; timing depends on you
Hardware drum machines (TR-8S, MPC) Tactile workflow, stage use Costs hundreds of dollars
Online metronome Practicing timing against a click No drum sounds or patterns

Use this tool to find the groove in minutes, then move to a DAW when the arrangement needs velocity, effects, and mixing. Pair it with the Scale Finder when your loop needs a bassline in key.

Frequently Asked Questions

In 4/4 time, one measure holds 4 quarter-note beats. A 16-step sequencer splits each beat into 4 sixteenth notes, giving 16 trigger steps per bar. Steps 1, 5, 9, and 13 are the quarter-note downbeats — the pulse everything else hangs on.

Start at 56–58%, the classic MPC pocket for boom-bap and 90s hip-hop. Laid-back neo-soul grooves sit around 60–62%. If the pattern starts stumbling instead of bouncing, back off 2–3%. Trap and drill usually stay near 0–15% swing and get their feel from triplet hi-hat rolls instead.

Divide 15,000 by your BPM. At 120 BPM each sixteenth-note step lasts 125 ms; at 128 BPM it's 117.2 ms; at 174 BPM (drum and bass) just 86.2 ms. Knowing the exact step length helps you program fills that land precisely on the bar line.

A polyrhythm fits two subdivisions into the same timespan — like 3 hits in the space of 2 beats. A polymeter layers two different bar lengths on the same pulse, so their downbeats drift and realign every lowest-common-multiple of steps. Both create hypnotic tension, but they feel completely different.

Click Export JSON to download your pattern as a text file mapping each drum to its active step numbers. In your DAW, set the same BPM and grid length, then enable the matching steps in its drum sequencer. Re-apply your swing percentage on the DAW's groove control and you're done.

This tool schedules hits on the Web Audio clock, so timing stays tight — but Bluetooth headphones and busy CPUs add output latency of 20–100 ms. Switch to wired headphones, close heavy tabs, and on mobile use a browser with Web Audio support (Chrome or Safari) for the best results.

The tresillo is a 3+3+2 accent pattern (hits on steps 1, 4, and 7 of an 8-pulse cycle) with Afro-Cuban roots. It's the rhythmic DNA of reggaeton's dembow, dancehall, Afrobeats, and countless pop hits. Program kick on 1, 4, 7, 10, 13 and snare accents on 4, 7, 12 to hear it instantly.

Use 16 steps for sketching and hypnotic loops, 32 steps when you want a two-bar call-and-response with a fill, and 64 steps for full four-bar phrases with an intro and turnaround. Longer patterns suit choruses and drops; shorter ones suit verses that need to stay out of the vocal's way.

Randomize generates a fresh pattern by randomly toggling steps across the drum voices — a creativity spark, not a finished beat. Treat the result as raw material: keep the 2–3 happy accidents, delete the clutter, and lock the kick and snare to your genre's blueprint. Hit it a few times until something inspires you.

Yes. Set the Division to Triplet 16, choose 140 BPM, and fill consecutive hat steps at the end of the bar (steps 13–16) for the classic roll. For pitch-bending 808-style rolls you'd need a DAW, but the rhythmic skeleton of modern trap programs perfectly on this grid.

This rhythm pattern maker is a free creative sketching tool for learning and inspiration. Patterns you program are yours to use in your own music.