Free Speed Calculator
Offspeed Retime Math
Work out the speed percentage for offspeed footage, see how long a clip becomes at your project frame rate, or solve backward from a duration you need to hit. Runs entirely in your browser - no account, no upload.
The frame rate the camera shot at.
Your timeline / project frame rate.
60 fps played at 24 fps runs at 40% speed - 2.5x slower.
24 / 60 x 100 = 40%In Avid, apply a Motion Effect / Timewarp at 40% speed. The clip runs 2.5x its recorded length.
How offspeed speed percentage works
A camera that records 60 frames every second and a timeline that plays 24 frames every second disagree about time. Hand the timeline 60 recorded frames and it takes 2.5 seconds to play them, so the action reads as slow motion. The speed percentage is simply the ratio of those two rates: playback frame rate divided by recorded frame rate.
Conforming never changes the frame count. A 600 frame clip is still 600 frames after the retime; it just occupies more or less of the timeline. That is why the calculator reports total frames alongside the new duration - the frames are what your vendor and your finishing house count.
Work the other way when a cut has to hit a fixed runtime. Divide the source duration by the duration you need: a 12 second take that has to land in 8 seconds runs at 150% speed.
Related tools
- Free AAF Retime Tool - conform whole AAF files to a project frame rate instead of doing the math clip by clip.
- Free EDL Editor - read timecodes, clip names, and durations straight out of an EDL.
- Retime Effect Application - how automated retime effects fit into a dailies and turnover workflow.
Doing this on every offspeed clip?
Developing Tank applies retime effects, tracks VFX shots, and builds turnover paperwork from your Avid sequences so the math happens once, automatically.