Methodology
The math behind every result.
Both tools use documented formulas and full-precision internal values. Device behavior, intonation compensation, and material tolerances remain the responsibility of the musician or builder.
Quarter-note duration
A minute contains 60,000 milliseconds, so quarter-note duration is 60,000 ÷ BPM.
Note relationships
Whole, half, quarter, eighth, sixteenth, thirty-second, and sixty-fourth notes are derived from the quarter note. Dotted values multiply duration by 1.5; triplets multiply it by 2/3.
Tap Tempo
Tap Tempo averages recent valid intervals, keeps the latest eight, filters one-off timing outliers, and uses an adaptive 2–5 second reset window. The longer first interval supports tempos down to 20 BPM.
Device limits and rounding
A device maximum only marks values as in or out of range; it does not remove them. Internal values are calculated before display rounding, with milliseconds retained to three decimal places.
Fret positions
Fret centerline n is measured from the nut usingL × (1 − 2^(-n/12)). Each position is calculated independently from the nut to prevent accumulated spacing error.
Physical exports
SVG uses millimeter dimensions. PDF layouts are tiled with 10 mm overlap and include a calibration ruler. Print at 100% / Actual Size and verify the ruler before cutting.
Reproduce these checks
These examples verify arithmetic and export geometry. They do not substitute for checking a physical instrument or a printed ruler.
- At 120 BPM, a quarter note is 500 ms, a dotted eighth is 375 ms, and an eighth-note triplet is 166.667 ms after rounding.
- At a 25.5-inch scale, fret 12 is 12.75 inches from the nut. Fret 24 is 19.125 inches from the nut.
- 25.5 inches equals 647.7 mm. Changing display units must preserve this physical length.
- A 100 mm calibration ruler must measure 100 mm after printing. Check every sheet before using a template.
References
- Tuneform — BPM conversion formula and studio timing
- StewMac — nut-based fret positioning and accumulated measurement error
- Stringjoy — why string tension values depend on construction and manufacturer data
Our fret tool calculates equal-tempered centerlines. It does not calculate saddle compensation. Our timing values describe rhythmic intervals; device response and playing feel must still be checked by ear.
Report a calculation discrepancy with your inputs, the expected value, and the result you received. Avoid including personal information in public reports.
Method revision: 2.1 · September 6, 2026