Free reference tools for working with motion picture film: calculate footage and running time, estimate the storage a scan will need, identify an unknown gauge, check reel capacity, and date a reel by its Kodak edge code.
Convert between footage, running time, and frame count for 8mm, Super 8mm, 9.5mm, 16mm, 35mm, and 65mm at any frame rate. Pick a film format and frame rate, then type a number into any one of the three boxes below (footage, running time, or frames) and the other two update automatically to show the matching values.
Calculate how much hard-drive space a film scan will require. Pick a resolution, delivery format, frame rate, and length, and see the total file size, the data rate, and the size per hour of footage.
Not sure what you have? Measure the width of the film and match the perforations. The strips below are drawn to scale relative to one another.
| Gauge | Film width | Perforations | How to spot it | Typical use |
|---|---|---|---|---|
| Regular 8mm | 8 mm | One edge, larger holes at the frame lines | Narrow film, sprocket holes down one side, small nearly square frames. Often on 3 inch (50 ft) reels. | Home movies, 1930s to 1960s |
| Super 8 | 8 mm | One edge, smaller holes centered on each frame | Same width as Regular 8 but tiny perfs and a bigger image. Usually came in a plastic cartridge. | Home movies, 1965 onward |
| 16mm | 16 mm | One edge (sound) or both edges (silent) | Twice the width of 8mm. A clear soundtrack stripe on one edge means a sound print. | Documentary, news, industrial, advanced home |
| Super 16 | 16 mm | One edge only | 16mm stock with a single row of perfs and a wider frame that reaches toward the other edge. | Production origination for widescreen |
| 35mm | 35 mm | Both edges, four holes per frame | Wide film with perforations down both sides. Exactly the same width as a 35mm still-photo negative. | Theatrical motion pictures |
A quick reference for how much running time a full reel holds, by gauge and reel size. Super 8 is shown at 18 fps and Regular 8 at 16 fps, their silent standards; 16mm and 35mm at 24 fps. Reel sizes are nominal outer diameters.
| Gauge | Reel size | Approx. length | Running time |
|---|---|---|---|
| Super 8 | 3 in | 50 ft | about 3.5 min |
| Super 8 | 5 in | 200 ft | about 13 min |
| Super 8 | 7 in | 400 ft | about 27 min |
| Regular 8 | 3 in | 50 ft | about 4 min |
| Regular 8 | 5 in | 200 ft | about 17 min |
| Regular 8 | 7 in | 400 ft | about 33 min |
| 16mm | 3⅝ in | 100 ft | about 2.75 min |
| 16mm | 5 in | 200 ft | about 5.5 min |
| 16mm | 7 in | 400 ft | about 11 min |
| 16mm | 10.5 in | 800 ft | about 22 min |
| 16mm | 11.5 in | 1000 ft | about 28 min |
| 16mm | 12.25 in | 1200 ft | about 33 min |
| 16mm | 13.75 in | 1600 ft | about 44 min |
| 16mm | 14.5 in | 1800 ft | about 50 min |
| 16mm | 15 in | 2000 ft | about 56 min |
| 35mm | ~10.5 in | 1000 ft | about 11 min |
| 35mm | 15 in | 2000 ft | about 22 min |
Need it exact? Use the Film footage calculator above to convert any footage, running time, or frame count for your gauge and frame rate.
For most of the twentieth century, Eastman Kodak printed a small symbol code along the edge of its motion-picture film, outside the perforations, to mark the year the stock was made. The symbols differ by the plant that coated the film, so choose the plant first. Then read the symbols left to right and pick them below, filling only as many as your film shows. This is the year the film was manufactured, not necessarily when it was shot or processed.
Pick the symbols you see, in order.
Alongside the date symbols, Kodak printed the word SAFETY on acetate stock, and a single dot above the word identified the factory that coated the film. The dot sits between two letters, not over one, and its position is what matters: read which pair of letters it falls between. Kodak began marking the Rochester plant around 1927 and the overseas plants in Canada and England around 1936.
