Note Length Calculator
Convert BPM into straight, dotted, or triplet note lengths with milliseconds, seconds, Hz, and sample counts.
Enter a tempo between 20 and 400 BPM.
Sample count changes with sample rate; 48 kHz is selected by default.
Quarter (1/4) · Straight · 120 BPM
Full Note-Length Table
Compare straight, dotted, and triplet values for the current BPM.
| Note | Straight | Dotted | Triplet |
|---|
Recent Calculations
Stored only for this browser session.
Accuracy, Privacy & Troubleshooting
Accuracy: Results are mathematically derived from the entered BPM and selected note subdivision. Musical feel and effect settings may still need artistic adjustment.
Privacy: All calculations happen in your browser. No audio or calculation data is uploaded.
Troubleshooting: If a result looks unexpected, confirm the BPM, subdivision type, and sample rate before using the value in your DAW or hardware.
The Note Length Calculator converts tempo into precise musical note durations for music production, sound design, mixing, and rhythm-based effects. Enter your BPM, choose a note value and timing type, and the calculator instantly shows the corresponding duration in milliseconds and seconds, tempo-synced frequency in Hertz, and audio sample count.
It is useful when a plugin, synthesizer, pedal, modulation effect, envelope, or other audio processor needs a numeric timing value instead of a musical subdivision. If you need a broader tempo conversion first, the main Tempo Calculator provides additional BPM-based calculations.
How to Use the Note Length Calculator
Start by entering the tempo of your project in BPM. You can type a custom tempo or use one of the quick BPM presets for faster setup.
Next, choose the musical note value you want to calculate, such as a whole, half, quarter, eighth, sixteenth, 32nd, 64th, or 128th note. Select Straight, Dotted, or Triplet timing depending on the rhythmic subdivision you need.
The results update immediately and can include:
- Note duration in milliseconds
- Duration in seconds
- Equivalent frequency in Hz
- Number of audio samples
- Beat length represented by the selected note
- A reference table of other note divisions at the same tempo
For sample calculations, select the same sample rate as your audio project, such as 44.1 kHz, 48 kHz, 96 kHz, or 192 kHz.
If you do not know your song’s tempo yet, use the BPM Finder before calculating note lengths.
How Note Length Is Calculated from BPM
The calculation starts with the duration of a quarter-note beat:
Quarter-note duration in milliseconds = 60,000 ÷ BPM
There are 60,000 milliseconds in one minute. Therefore, at 120 BPM:
60,000 ÷ 120 = 500 ms
A quarter note at 120 BPM lasts 500 milliseconds. This BPM-to-time relationship is also used by established audio timing calculators.
Other note values are calculated relative to the quarter note. At the same 120 BPM tempo:
| Note Value | Straight Duration |
|---|---|
| Whole note | 2000 ms |
| Half note | 1000 ms |
| Quarter note | 500 ms |
| Eighth note | 250 ms |
| Sixteenth note | 125 ms |
| 32nd note | 62.5 ms |
| 64th note | 31.25 ms |
For a simpler BPM-to-time conversion workflow, you can also use the dedicated BPM to MS Calculator.
Straight, Dotted, and Triplet Note Lengths
A note subdivision can have different rhythmic forms even when the BPM stays unchanged.
A straight note uses its normal duration.
A dotted note lasts 1.5 times the duration of the corresponding straight note.
Dotted duration = straight duration × 1.5
A triplet subdivision used by the calculator applies a two-thirds multiplier to the equivalent straight duration:
Triplet duration = straight duration × 2 ÷ 3
At 120 BPM, for example:
| Timing | Quarter-Note Duration |
|---|---|
| Straight | 500 ms |
| Dotted | 750 ms |
| Triplet | 333.33 ms |
Dotted and triplet timing are particularly useful for creating rhythmic delay patterns instead of repeats that always fall directly on the normal beat division. Production-oriented delay calculators similarly use standard, dotted, and triplet subdivisions for tempo-synchronized effects.
If delay timing is your main goal, the BPM Delay Calculator provides a workflow focused specifically on delay subdivisions.
Understanding Milliseconds, Seconds, Hertz, and Samples
The calculator expresses the same musical timing relationship in several forms because different audio tools expect different types of input.
Milliseconds (ms) are particularly useful for delay times, pre-delay settings, envelopes, gates, and other time-based controls.
Seconds (s) represent the same duration in a larger unit and are convenient for longer note values.
Hertz (Hz) expresses how many complete cycles of the selected duration occur each second. The relationship is:
Frequency = 1 ÷ duration in seconds
or:
Hz = 1000 ÷ milliseconds
For example, a 500 ms duration corresponds to 2 Hz.
Tempo-related Hertz values can provide useful starting points when an LFO or modulation control accepts frequency rather than musical note divisions. Tempo-synchronized LFO calculations are also used in audio-production timing workflows.
Audio samples depend on both duration and project sample rate:
Samples = duration in seconds × sample rate
A 500 ms note at a 48,000 Hz sample rate contains:
0.5 × 48,000 = 24,000 samples
Make sure the selected sample rate matches your actual DAW session before using the sample result.
Using Note Lengths for Delay and Reverb
Tempo-based note lengths are useful when a delay device or plugin requires a manual millisecond value.
For example, at 120 BPM:
- Quarter-note delay = 500 ms
- Eighth-note delay = 250 ms
- Sixteenth-note delay = 125 ms
- Dotted eighth = 375 ms
- Eighth-note triplet ≈ 166.67 ms
An eighth-note delay at 120 BPM being 250 ms follows the same timing relationship documented in established BPM/delay references.
These values are mathematical synchronization points rather than rules about what will sound best. A producer may intentionally shorten, lengthen, offset, or automate a delay for groove, width, texture, or movement.
For deeper production context, see how BPM is used in music production.
Using Note Lengths for LFOs and Modulation
Some synthesizers and effects let you synchronize modulation directly to BPM. Others ask for an LFO rate in Hertz.
When the device only accepts Hz, the calculator’s frequency output gives you the equivalent cycle rate for the selected musical duration.
This can be useful for:
- Tremolo
- Filter modulation
- Auto-pan
- Phaser movement
- Chorus modulation
- Rhythmic amplitude changes
- Tempo-based automation
Treat the calculated value as a synchronized starting point. Different effects respond differently depending on modulation depth, phase, waveform, stereo configuration, and musical context.
Note Lengths and Time Signatures
BPM describes tempo, while the time signature describes how beats are grouped and notated. They are related concepts, but they are not interchangeable.
For example, two pieces can both run at 120 BPM while using different meters and producing very different rhythmic feels. If you want to understand that distinction in more detail, read the guide to time signatures.
You can also hear a steady tempo practically with the Online Metronome or create a practice reference using the Click Track Generator.
Accuracy and Limitations
The calculator uses deterministic mathematical relationships between BPM, note subdivisions, duration, frequency, and sample rate. It does not analyze uploaded audio or determine whether a timing value is musically appropriate for a specific song.
Calculated sample counts depend on the sample rate you select. If your project runs at 96 kHz but the calculator is set to 48 kHz, the displayed sample count will not match the project.
Tempo-synchronized values can also differ from the final settings you choose by ear. Humanized performances, swing, tempo automation, groove templates, unusual meters, and intentional timing offsets can all make a slightly different value more suitable.
If BPM itself is unfamiliar, the guide explaining what BPM means provides the underlying tempo concept.
Privacy and Browser Processing
The Note Length Calculator performs its calculations directly in your browser. The calculation itself does not require uploading an audio recording.
Recent calculations, when the history feature is used, are kept for the current browser session using session storage and can be cleared with the Clear History control.
This makes the tool suitable for quick calculations during a production session without requiring an account or an audio upload.
Frequently Asked Questions
How do you calculate note length from BPM?
Divide 60,000 by the BPM to find the duration of a quarter note in milliseconds. Then multiply that result according to the selected note division. For example, an eighth note is half the duration of a quarter note.
How long is a quarter note at 120 BPM?
A quarter note at 120 BPM lasts 500 milliseconds, or 0.5 seconds.
How long is an eighth note at 120 BPM?
A straight eighth note lasts 250 milliseconds because it is half the duration of the 500 ms quarter note.
What is a dotted eighth note at 120 BPM?
A straight eighth note at 120 BPM is 250 ms. Multiplying by 1.5 gives a dotted eighth-note duration of 375 ms.
What is an eighth-note triplet at 120 BPM?
Using the calculator’s triplet relationship, 250 × 2/3 gives approximately 166.67 milliseconds.
How do I convert a note duration to Hz?
Divide 1 by its duration in seconds. A 0.5-second note duration corresponds to 2 Hz.
Why does sample rate change the sample result?
Sample rate specifies how many audio samples occur every second. The same 500 ms duration contains 22,050 samples at 44.1 kHz but 24,000 samples at 48 kHz.
Can I use these values in a delay pedal or plugin?
Yes, when the device accepts manual timing in milliseconds and the value falls within its supported range. Many modern effects also provide native tempo synchronization, so manual conversion may not always be necessary.
Does a tempo-synced delay always sound better?
No. Synchronization gives you a mathematically related starting point. The most appropriate setting depends on the rhythm, arrangement, groove, and effect you want to create.