Bulk Roll Calculator

Some 35mm film is available in bulk rolls, which is fairly easy to load into standard 135 film cartridges.

Bulk loading can save you money — but that’s not all it can do. You can load any number of frames per roll (40, 36, 24, 12, 8, whatever), which is very useful when testing cameras and exposures. This is also helpful with the half-frame format, which may take forever to use up. Or you can bulk-load to create your own film brand if you wish.

Unfortunately, there’s no easy way to budget your film or estimate how many canisters you can fill with your bulk roll (until now). You may hunt for formulas or random forum posts elsewhere, but none will give you a complete answer for non-standard film lengths, or a way to convert film frames to inches or cm.

Bulk Roll Calculator solves that problem. It does all the math with its helpful UI in inches and cm and helps you convert any number of frames to lengths and back. Here’s what else it can do:

✅ Calculate the number of rolls you’ll be getting from any bulk roll length. Including the adjustable leader/safety margin.

✅ Calculate the number of frames you can have per canister for a given number of rolls you’d like to squeeze out of your bulk loader.

✅ Know how much extra film you’ll have left with the above calculations.

Beware that while the calculations will always be exact, the nature of loading film by hand will often yield some imperfections — so budget to use a bit more film.

The Bulk Roll Calculator web app is available for all GOLD members. It works on all devices and does not require a download.