Exposure Value (EV) Calculator

How to use

1. 1Pick a mode. Settings to EV computes the exposure value from your camera settings; EV to settings works backward from a target EV to equivalent aperture and shutter pairs.
2. 2In Settings to EV, enter an aperture (f-number), a shutter speed as a fraction like 1/250 or seconds like 2, and an ISO. Use the preset chips for the standard values. Read the scene EV (at ISO 100) and the EV at your ISO.
3. 3In EV to settings, type an exposure value or tap a scene from the Sunny 16 and night guide, then enter the ISO.
4. 4Choose whether to solve for shutter or aperture, fix the other setting, and read the required value. Scan the equivalent exposures table to trade aperture for shutter at the same EV.
5. 5Switch the table between full, half, and third stops, then use the Copy buttons to save the result or the full table. Everything runs in your browser, so nothing is uploaded.

About this tool

Exposure Value (EV) Calculator turns the three exposure settings on any camera, aperture, shutter speed, and ISO, into a single light value, and lets you work the calculation in both directions. In Settings to EV mode you type an f-number, a shutter speed (as a fraction like 1/250 or a number of seconds like 2), and an ISO, and the tool reports the exposure value using the standard definition EV = log2(N squared / t), where N is the f-number and t is the shutter time in seconds. The result is normalised to ISO 100, the convention light meters and printed EV tables use, so the number tracks the brightness of the scene rather than the sensitivity you happen to be shooting at; a second readout shows the in-camera EV at your actual ISO for when you are comparing against a meter set to that value. The tool also names the closest typical scene, so an answer near EV 15 is flagged as bright sun with distinct shadows, the basis of the Sunny 16 rule. In EV to settings mode you pin an exposure value (or click a scene from the Sunny 16 and night-sky guide), choose whether to solve for shutter or aperture, fix the other setting, and read the required value. Below that, a reciprocity table lists every equivalent aperture and shutter pair at that EV and ISO, at full, half, or third stop steps, so you can swap depth of field for motion blur while keeping the exposure constant: f/2.8 at 1/500 and f/8 at 1/60 are the same exposure, and the table makes that trade obvious. A light value reference chart covers common situations from snow in bright sun (EV 16) down through overcast, interiors, street scenes at night, the full moon, and the milky way, giving film and manual shooters a starting point when no meter is handy. Every output can be copied as plain text for a notebook, a shot list, or a forum post. The math is deterministic and runs entirely in your browser, so the settings you enter are never uploaded or stored. This is an exposure calculator, not a light meter: it tells you which settings are equivalent and what EV your settings represent, but the correct EV for a given scene still depends on the actual light, your metering mode, and any creative under or over exposure you want.

Free to use. Works in your browser. No signup, no login.