Exposure Calculator
This exposure calculator uses the standard Exposure Value (EV) formula to find equivalent exposures. Pick which setting you want to solve for, adjust the other two, and the calculator instantly finds the matching aperture, shutter speed, or ISO that keeps your exposure the same.
How it works
Exposure Value (EV) combines aperture, shutter speed, and ISO into a single number: EV = log2(N² / t) − log2(ISO / 100). Two combinations with the same EV produce the same overall exposure. Choose which field to solve for, then change either of the other two — the calculator recalculates the solved field so the EV stays locked to whatever it was the moment you picked it.
Tip
Opening the aperture by one stop (e.g. f/4 to f/2.8) lets in twice as much light, so you'd need to halve the shutter time or halve the ISO to keep the same exposure. Use this calculator to find that match instantly instead of doing the math by hand.
Why did the value jump when I switched what I’m solving for?
It shouldn't — switching the solved field locks in the exposure value of your current three settings first, so nothing changes until you adjust one of the free inputs afterwards.
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