How playback speed changes video length
Playing a video faster divides its length by the speed. The formula is:
time at speed = original length ÷ speedA 60 minute video at 1.5x takes 60 ÷ 1.5 = 40 minutes. At 2x it takes 30 minutes. The time saved is the original length minus the new length, and as a share of the original it is 1 − 1 ÷ speed: 20% at 1.25x, 33% at 1.5x, 50% at 2x.
Common speeds for a one hour video
| Speed | Watch time | Time saved |
|---|---|---|
| 0.75x | 1:20:00 | 20 min longer |
| 1.25x | 48:00 | 12 min (20%) |
| 1.5x | 40:00 | 20 min (33%) |
| 1.75x | 34:17 | 26 min (43%) |
| 2x | 30:00 | 30 min (50%) |
| 3x | 20:00 | 40 min (67%) |
Notice that each step up saves less than the one before. Going from 1x to 1.5x saves 20 minutes an hour, but going from 2x to 3x saves only 10 more.
Working out a playlist or course
Enter the typical length of one video and the number of videos. The calculator multiplies them and shows the total at each speed. If the videos vary a lot in length, enter the course’s total running time with the count set to 1 instead; most course platforms list it on the overview page.
Finding the speed you need
Type how long you have into “Speed needed to finish in”. The speed needed is the total length divided by the time you have. For example, a 3 hour course in 2 hours needs 1.5x. The answer is rounded up to the next standard setting so you finish in time.
Which speed should you pick?
- 1.25x to 1.5x suits most talks, lectures and tutorials. Speech stays easy to follow.
- 1.75x to 2x works for content you partly know, or slow speakers.
- Slow it down (0.75x) for dense material, code walkthroughs or a language you are learning.
YouTube offers speeds from 0.25x to 2x in steps of 0.25 (and custom steps of 0.05). Many other players, and browser extensions, go up to 3x or beyond.
If you make the videos
Viewers speed up videos mostly to skip pauses and slow stretches. Cutting silences and filler words before you share does the same thing for everyone, at normal speed, without making your voice sound rushed.
FAQ
How long is a 1 hour video at 1.5x speed?
40 minutes. Divide the length by the speed: 60 ÷ 1.5 = 40. You save 20 minutes, a third of the original time.
How much time does 2x speed save?
Half. Any video at 2x takes 50% of its normal length, so a 30 minute video takes 15 minutes.
How long is a 10 minute video at 1.25x?
8 minutes. 10 ÷ 1.25 = 8, which saves 2 minutes (20%).
How do I calculate what speed I need to watch a video in less time?
Divide the video’s length by the time you have. A 90 minute video in 60 minutes needs 90 ÷ 60 = 1.5x. Round up to the next setting your player offers.