Frame Rate Converter Calculator

It's the target frame rate divided by the source frame rate, expressed as a percentage. A value under 100% means the footage will play back slower than normal if you simply relabel it at the new rate; a value over 100% means it will play faster, since more or fewer frames now represent the same span of real time.

Playback Speed is purely a ratio of target to source frame rate -- it describes how fast the footage runs relative to normal, which has nothing to do with how long the original clip is. Source Duration only changes the New Duration and total frame count outputs, both of which scale directly with clip length.

Interpolation is only relevant when converting to a higher frame rate than the source, since there's no way to show more frames per second than you actually captured without generating new ones. Converting to a lower target rate never requires interpolation -- the extra source frames are simply dropped or, if you retime instead of just relabeling, played back at a different speed.

At a 30-to-24 ratio of about 1.25x, this calculator classifies it as light interpolation, meaning roughly 25% of the output frames need to be synthesized rather than heavily regenerated. It becomes "heavy" once the target rate is more than double the source, where the majority of displayed frames would have to be invented.