Free editing tool
Video speed and duration calculator
Enter a source duration and speed multiplier. The calculator returns the exact output duration and the amount of viewer time saved or added.
3m 20s saved from the source duration at 1.5×.
What the result means
Speed changes divide duration. A 12-minute clip at 1.5× becomes 8 minutes; at 0.75× it becomes 16 minutes. Accelerating the entire recording can make speech hard to follow, so product demos often work better when only repetitive waits, typing, or loading segments are sped up.
Formula or method
output duration = source duration ÷ speed multiplier. Time saved = source duration − output duration.
Boundaries to remember
- Changing speed can alter pitch unless the editor applies pitch correction.
- Very fast cursor motion may become hard to follow even when the total duration looks attractive.
- Do not use speed to hide a confusing workflow; cut dead time and clarify the sequence first.
Use the result
From calculation to a cleaner recording
Cut before accelerating
Remove mistakes, duplicate navigation, and empty waits first. A concise 1× explanation is usually clearer than an unedited take at 2×.
Speed only the repetitive segment
Use 1.5× or 2× for typing, setup, build output, or a progress indicator while keeping spoken explanation at natural speed.
Preview the transition
A speed change needs a clean entry and exit. Rekort lets you split the timeline, assign 0.5×, 0.75×, 1×, 1.5×, 2×, 3×, or 4× to a segment, and ripple-delete material that adds no value.
Questions
How long is a 10-minute video at 1.5× speed?
Six minutes and 40 seconds. Divide 600 source seconds by 1.5.
How long is a one-hour video at 2× speed?
Thirty minutes. At 2×, every source minute takes 30 seconds to play.
What speed is best for a software tutorial?
Keep explanation and decision points near 1×. Speed up repetitive typing, installs, builds, and loading states only as far as the viewer can still track what changed.
Can I slow down a screen recording?
Yes. A 0.5× speed doubles the duration and can help reveal a fast interaction, although source frame rate limits how smooth slowed footage can look.
Can Rekort use different speeds in one video?
Yes. Split the recording into segments and choose a speed for each segment. Rekort's current editor offers 0.5× through 4× presets.
Put the answer into the recording.
Rekort records screen, webcam, system audio, and microphone on macOS, then adds auto-zoom, timeline corrections, backgrounds, and local MP4 or GIF export.