How long will the roll run?
Choose the camera’s capture rate to estimate how long the film lasts during recording. The separate playback rate shows the running time of those same frames in your scan or edit.
Time is shown as minutes:seconds.milliseconds, or hours:minutes:seconds.milliseconds. These are elapsed durations, not SMPTE timecode labels. Reserve is a combined allowance you choose for loading, heads/tails and waste; zero is the default, not a recommended loading allowance.
One roll. Two useful durations.
whole frames = floor(usable feet × nominal frames per foot)
recording seconds = whole frames ÷ camera fps
playback seconds = whole frames ÷ playback fps
The format determines the nominal footage-to-frame factor. The emulsion or stock speed does not change that factor. Super 16 uses the same nominal frame advance as standard 16 mm; its image area differs.
| Film format | Frames per foot | Feet/min at 24 fps |
|---|---|---|
| 16 mm / Super 16 | 40 | 36 |
| 35 mm · 2-perf | 32 | 45 |
| 35 mm · 3-perf | 64/3 ≈ 21.3333 | 67.5 |
| 35 mm · 4-perf | 16 | 90 |
The 3-perf factor stays as 64/3 in the calculation, not the rounded display value 21.33. Only the final available frame count is rounded down. This is a conservative nominal-length estimate, not a reconstruction of frame boundaries from KEYKODE or a measured perforation pitch.
Feet/metres conversion uses 1 ft = 0.3048 m exactly. Fractional rate labels use 24000/1001, 30000/1001 and 60000/1001 fps. Input length and reserve are handled as exact decimal fractions before whole-frame rounding.
Examples for a camera report.
| Setup | Whole frames | Recording time |
|---|---|---|
| 35 mm 4-perf · 24 fps · no reserve | 6,400 | 4 min 26.667 s |
| 16 mm · 24 fps · no reserve | 16,000 | 11 min 6.667 s |
| 35 mm 3-perf · 24 fps · no reserve | 8,533 | 5 min 55.542 s |
| 35 mm 4-perf · 24 fps · 20 ft reserve | 6,080 | 4 min 13.333 s |
| 35 mm 4-perf · 96 fps · no reserve | 6,400 | 1 min 6.667 s |
For the final row, the roll lasts about 66.667 seconds in the camera. Those 6,400 frames play for about 266.667 seconds at 24 fps. Changing the playback rate does not put more film in the magazine.
Planning several rolls? Use the shooting-ratio and film requirement planner to combine finished duration, shooting ratio and per-roll reserve.
Carry the assumptions into post.
Keep film gauge, perf arrangement, capture rate, playback rate and roll identity with the camera report. For a scan, retain the first image identifier as well as the total frame count.
Continue with film footage, frame counts and running time for the full method, or film-to-digital delivery for conform speed and scan workflows. Timecode Pro can help with timecode and film-unit arithmetic; this browser tool is a separate nominal-roll planning example.
One-time purchases. Mac and iPhone/iPad sold separately.iPhone/iPad app listed as Timecode on the App Store.
Technical references
- Kodak: The Essential Reference Guide for Filmmakers — 35 mm footage and 2-/3-perf movements, and Super 16
- Kodak: film calculator and footage-planning reference
- NASA archive: photographic-material specification, Appendix A, A.1(a), PDF page 30 — 40 frames per foot
- NIST: conversion factors for SI units
These references establish the conventions. Numerical examples are calculated here from the stated factors; none is a guarantee of a particular loaded magazine’s usable runtime.