Try the calculator
Runs in your browser. No signup, upload or saved inputs.
When this is useful
This is a planning calculation, not a video editor. It can reveal how much time a speed change would save, but it cannot determine whether the viewer can still understand the product interaction.
How to use this calculator
- Enter the original duration in seconds and a positive speed multiplier. Use 1 for unchanged speed.
- Compare the resulting duration with the scene budget and note whether the speed change affects narration or important processing-time expectations.
- Preview an actual edit before choosing the treatment. Prefer removing irrelevant waiting or splitting the story when a fast clip makes the interface difficult to follow.
Worked calculation
An illustrative 45-second clip played at 1.5× lasts 30 seconds. At 0.75× it lasts 60 seconds. The calculation assumes one constant speed across the entire clip, without freezes or transition overlaps.
Formula and units
Output seconds = original seconds ÷ speed multiplier.
Limits and checks
Speed ramps need separate segment calculations. Editors can round to frame boundaries, and audio time-stretch settings affect the listening experience. If a meaningful product process is accelerated, make that clear rather than implying unsupported performance.
Your next step
Keep a normal-speed source and compare the accelerated version at the intended viewing size before approving it.
References and scope
Examples are illustrative production guidance, not measured customer results. General workflows are not promises of product compatibility. Read our editorial approach and current Demovela scope.