How long at this playback speed?
Type the length of a video, podcast or lecture and the playback speed. The playback speed calculator divides the length by the speed to give the new time and the time you save. Or type the time you have to get the speed you need.
- Time at this speed
- 1 hour
At this speed it takes 1 hour.
- Time saved
- 30 minutes
- Share of the original time
- 66.7%
- Length at 1×
- 1 hour, 30 minutes
Time at this speed: 1 hour. At this speed it takes 1 hour.
How to calculate
Works out how long a video, podcast or lecture takes at a playback speed such as 1.5× or 2×, and the time saved, or the speed you need to finish it in the time you have.
Example with the default inputs (Find Time at a speed, Hours 1, Minutes 30, Seconds 0, Playback speed 1.5): At this speed it takes 1 hour.
Method: time at speed = length ÷ speed, rounded half up to the second; speed needed = length ÷ time you have.
- The whole recording plays at one speed, with no skipped parts or pauses.
- Times are shown to the nearest second, a half second rounded up; the time saved is the difference of the shown times.
- Players offer set speeds (often 0.25× to 2×, some up to 3× or more); round the speed you need up to one your player has.
Worked examples
Each example is checked against the calculator on every build.
- Find Time at a speed, Hours 1, Minutes 30, Seconds 0, Playback speed 1.5 gives Time at this speed 1 hour, Time saved 30 minutes.Source: 1 h = 3,600 s and 1 min = 60 s (NIST Special Publication 811, Appendix B.8, https://www.nist.gov/pml/special-publication-811, retrieved 2026-10-02): 5,400 s ÷ 1.5 = 3,600 s
- Find Time at a speed, Hours 0, Minutes 45, Seconds 10, Playback speed 1.25 gives Time at this speed 36 minutes, 8 seconds, Time saved 9 minutes, 2 seconds, Share of the original time 80%.Source: 1 h = 3,600 s and 1 min = 60 s (NIST Special Publication 811, Appendix B.8, https://www.nist.gov/pml/special-publication-811, retrieved 2026-10-02): 2,710 s ÷ 1.25 = 2,168 s
- Find Speed I need, Hours 2, Minutes 0, Seconds 0, Hours 1, Minutes 20, Seconds 0 gives Speed you need 1.5, Time at this speed 1 hour, 20 minutes.Source: 1 h = 3,600 s and 1 min = 60 s (NIST Special Publication 811, Appendix B.8, https://www.nist.gov/pml/special-publication-811, retrieved 2026-10-02): 7,200 s ÷ 4,800 s = 1.5×
- Find Time at a speed, Hours 0, Minutes 0, Seconds 7, Playback speed 2 gives Time at this speed 4 seconds, Time saved 3 seconds.Source: 1 h = 3,600 s and 1 min = 60 s (NIST Special Publication 811, Appendix B.8, https://www.nist.gov/pml/special-publication-811, retrieved 2026-10-02): 7 ÷ 2 = 3.5 s, shown as 4 s
How it works
The length L is typed as hours, minutes and seconds and counted in whole seconds: L = 3,600 × hours + 60 × minutes + seconds (empty parts count as 0).
- Time at a speed s = L ÷ s, rounded to the nearest whole second, a half second rounded up. The speed is read as the exact decimal you typed, so 2,710 ÷ 1.25 is exactly 2,168 seconds.
- Speed you need = L ÷ T, where T is the time you have in whole seconds. The time at that speed is then T.
- Time saved = L − the rounded new time, when positive; time added = the rounded new time − L, when the new time is longer.
- Share of the original time = (L ÷ s) ÷ L × 100%, which is 100% ÷ s.
Rules
- Hours are whole numbers from 0 to 10,000, minutes and seconds from 0 to 59. The length must be more than 0 seconds, and so must the time you have.
- The speed is from 0.1× to 16×.
Output format. Times as hours, minutes and seconds; the speed you need to 2 decimal places; the share as a percent to 1 decimal.
Worked examples by hand
90 minutes at 1.5×. 5,400 ÷ 1.5 = 3,600 s = 1 h. Saved: 30 min.
45 min 10 s at 1.25×. 2,710 ÷ 1.25 = 2,168 s = 36 min 8 s. Saved: 2,710 − 2,168 = 542 s = 9 min 2 s. Share: 100 ÷ 1.25 = 80%.
2 hours in 1 h 20 min. 7,200 ÷ 4,800 = 1.5×.
7 seconds at 2×. 7 ÷ 2 = 3.5 s, rounded up to 4 s. Saved: 3 s.
Other questions people ask
How long is a video at 1.5× speed?
Divide the length by the speed. A 90 minute lecture at 1.5× takes 90 ÷ 1.5 = 60 minutes, so you save 30 minutes. At 2× it takes 45 minutes, half the time.
How much time does 1.25× save?
At 1.25× a recording takes 1 ÷ 1.25 = 80% of its length, so you save 20%. A 45 minute 10 second podcast takes 36 minutes 8 seconds, 9 minutes 2 seconds less.
What speed do I need to finish in time?
Divide the length by the time you have. To watch a 2 hour course in 1 hour 20 minutes, you need 120 ÷ 80 = 1.5×. If your player has only set speeds, pick the next one up.
Does a slower speed add time?
Yes. Below 1× the recording takes longer: 30 minutes at 0.75× takes 40 minutes, 10 minutes more. The calculator shows the time added instead of the time saved.
How are the seconds rounded?
The new time is the exact length divided by the exact speed, rounded to the nearest second, with a half second rounded up. A 7 second clip at 2× is 3.5 seconds, shown as 4 seconds.