Reciprocal Rule Shutter Speed Calculator
Fill in the values and the answer updates as you type.
How the Reciprocal Rule Shutter Speed Calculator works
The reciprocal rule says the shutter speed should be at least 1 ÷ (focal length × crop factor). Each stop of image stabilization doubles the allowed exposure time. High-resolution sensors and shaky hands call for a faster speed, and the rule is a starting point, not a guarantee. Use the real lens focal length, not the equivalent value, and enter the crop factor separately. Example: A 200 mm lens on full frame needs about 1/200 s without stabilization, but 1/25 s with 3 stops of stabilization.
Inputs and results
The Reciprocal Rule Shutter Speed Calculator takes 3 inputs and gives 3 results.
What you enter
- Focal length (mm) — starts at 200.
- Crop factor — starts at 1.
- Image stabilization (stops) — starts at 3.
What you get
- Slowest safe hand-held shutter speed
- Without stabilization
- Gain from stabilization (×)
Example: Reciprocal Rule Shutter Speed Calculator with the starting values
With focal length 200 mm, crop factor 1 and image stabilization 3 stops, the calculator returns:
| Slowest safe hand-held shutter speed | 1/25 s |
|---|---|
| Without stabilization | 1/200 s |
| Gain from stabilization (×) | 8 |
Change any value above and the results update straight away.
Reciprocal Rule Shutter Speed Calculator FAQ
How do I use the Reciprocal Rule Shutter Speed Calculator?
Enter focal length, crop factor and image stabilization in the fields, then read slowest safe hand-held shutter speed, without stabilization and gain from stabilization (×) 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 Reciprocal Rule Shutter Speed Calculator calculate?
Slowest shutter speed you can hand-hold without blur. It returns slowest safe hand-held shutter speed, without stabilization and gain from stabilization (×) from the 3 values you provide.
What values does the Reciprocal Rule Shutter Speed Calculator start with?
It opens with focal length 200 mm, crop factor 1 and image stabilization 3 stops 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 Reciprocal Rule Shutter Speed 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 Reciprocal Rule Shutter Speed 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.