Slow Motion Calculator
Fill in the values and the answer updates as you type.
How the Slow Motion Calculator works
Slow-down factor = recording fps ÷ playback fps, and the final clip length is the real action time multiplied by that factor. The 180° shutter rule suggests a shutter time of 1 ÷ (2 × recording fps), which gives natural motion blur. High frame rates need more light and fill cards faster. Example: Shooting at 120 fps for playback at 24 fps slows action 5×, so 5 seconds becomes 25 seconds.
Inputs and results
The Slow Motion Calculator takes 3 inputs and gives 4 results.
What you enter
- Recording frame rate (fps) — starts at 120.
- Playback frame rate (fps) — starts at 24.
- Real-time action length (s) — starts at 5.
What you get
- Slow-down factor (×)
- Final clip length (seconds)
- Frames recorded
- Shutter speed for the 180° rule
Example: Slow Motion Calculator with the starting values
With recording frame rate 120 fps, playback frame rate 24 fps and real-time action length 5 s, the calculator returns:
| Slow-down factor (×) | 5 |
|---|---|
| Final clip length (seconds) | 25 |
| Frames recorded | 600 |
| Shutter speed for the 180° rule | 1/240 s |
Change any value above and the results update straight away.
Slow Motion Calculator FAQ
How do I use the Slow Motion Calculator?
Enter recording frame rate, playback frame rate and real-time action length in the fields, then read slow-down factor (×), final clip length (seconds), frames recorded and shutter speed for the 180° rule in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Slow Motion Calculator calculate?
Slow-down factor and final clip length from frame rates. It returns slow-down factor (×), final clip length (seconds), frames recorded and shutter speed for the 180° rule from the 3 values you provide.
What values does the Slow Motion Calculator start with?
It opens with recording frame rate 120 fps, playback frame rate 24 fps and real-time action length 5 s so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Slow Motion Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Slow Motion Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.