Slow Motion Frame Calculator

Slow Motion Frame Calculator

Shot high frame rate footage for a slow-motion effect? This calculator tells you the resulting slowed-down playback length.

Slow-Motion Factor = Capture Frame Rate / Playback Frame Rate
Final Playback Length = Original Clip Length x Slow-Motion Factor

Example

Footage captured at 120fps, played back at 30fps, 5-second original clip:

Slow-Motion Factor = 4.0x → 20.0 seconds of slow-motion footage

Why Capturing at a Higher Frame Rate Is Necessary

Slow motion works by capturing more frames per second than the video will ultimately play back at - stretching that same number of frames across a longer playback duration is exactly what creates the smooth slow-motion effect, since every original real-time moment now spans more playback time.

Why Simply "Slowing Down" Normal Footage Looks Choppy

Digitally slowing down footage that was captured at a normal frame rate (rather than actually recorded at a higher frame rate) produces choppy, stuttering motion, since there aren't enough real captured frames to stretch smoothly across the extended playback time - true slow motion requires the extra frames to already exist.