Reciprocal Rule Shutter Speed Calculator
Slowest shutter speed you can hand-hold without blur.
How it 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.
FAQ
Is this calculator free?
Yes. No signup is needed and nothing you enter is stored.
Is the result exact?
Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.
Do my numbers leave my device?
No. The calculation runs in your browser.