DataCalc
Motion Picture Film Calculator
Motion picture film stock calculator. Calculate 16mm and 35mm film footage, runtime, and stock needed. Essential tool for film productions and cinematographers.
How this calculator works
The Motion Picture Film Calculator converts between film length in feet, running time, and number of rolls for 16mm and 35mm production. Enter a footage amount to get runtime, or a target runtime to see how much stock you need to order.
Film math is fixed by sprocket geometry: 35mm 4-perf runs 16 frames per foot, 16mm runs 40 frames per foot. From there, frame rate determines everything — at 24 fps, 35mm 4-perf burns 90 feet per minute while 16mm uses just 36.
Runtime from footage (35mm 4-perf @ 24 fps)
Runtime (min) = Feet ÷ 90 (16mm: Feet ÷ 36)
Example: a 1,000 ft roll of 35mm at 24 fps ≈ 11 minutes of runtime.
| Format | Frames per foot | Feet per minute | Runtime per 1,000 ft |
|---|---|---|---|
| 35mm 4-perf | 16 | 90 | ≈11.1 min |
| 35mm 3-perf | 21.3 | 67.5 | ≈14.8 min |
| 35mm 2-perf | 32 | 45 | ≈22.2 min |
| 16mm / Super 16 | 40 | 36 | ≈27.8 min |
Frequently asked questions
How long does a 1,000 ft roll of 35mm last?
About 11 minutes at 24 fps in standard 4-perf. 3-perf stretches the same roll to roughly 15 minutes, and 2-perf to about 22 — one reason those formats are chosen for budget-conscious film shoots.
How much film stock does a feature need?
Multiply target runtime by your shooting ratio. A 100-minute film shot at a 10:1 ratio needs 1,000 minutes of stock — about 90,000 ft of 35mm 4-perf. The calculator converts your ratio and format into feet and rolls.
What is the difference between 2-perf, 3-perf, and 4-perf?
The number of perforations advanced per frame on 35mm. Fewer perfs per frame means a shorter, wider negative area and less stock consumed per minute — 3-perf saves about 25% versus 4-perf and suits 16:9 and scope extraction well.
Does shooting at higher frame rates use more film?
Yes, linearly: 48 fps consumes exactly twice the stock of 24 fps. Slow-motion work on film is budgeted in feet per second, not per minute.
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