Camera Exposure Value (EV) Calculator

What is a Camera Exposure Value (EV) Calculator?

A Camera Exposure Value (EV) Calculator helps you solve for the third value when you already know two of these three items: aperture, shutter speed, and exposure value. It turns the core relationship in the exposure triangle into numbers you can check immediately, which is especially useful for manual shooting and exposure practice.

This tool uses the ISO 100 baseline formula. You can calculate scene EV from an aperture and shutter-speed pair, or solve for the shutter speed you need from a target EV and an aperture choice. It also shows equivalent-EV combinations so you can see at a glance how to trade aperture against shutter speed while holding brightness steady.

When this tool is useful

Exposure decisions have to happen quickly whenever you move between landscapes, portraits, interiors, and night scenes. In practice, it helps more to see how aperture and shutter speed compensate for each other than to memorize EV numbers alone. This tool works well both when you are planning a shot in advance and when you need a quick check during a session.

• Manual-mode practice – When you want to set aperture and shutter speed yourself and check how bright the current combination really is
• Shutter-speed back-solving – When you already know your target aperture and EV and want the matching shutter speed quickly
• Aperture back-solving – When you set a shutter speed first to control blur and then need the aperture that fits
• Equivalent-EV comparison – When you want to trade background blur against subject motion while keeping the same brightness
• Learning exposure – When you want a better feel for what EV 15 or EV 8 looks like in a real scene

Key features

This Camera EV Calculator does more than return a single number. It also gives you the context you need to interpret the current combination, including nearby standard values, a scene-brightness guide, and an equivalent-EV table on the same screen so you can make exposure decisions faster.

• Three calculation modes – Switch between EV, shutter, and aperture calculations on one screen
• Live result updates – Results change immediately when you change a value, making repeated checks easy
• Equivalent-EV table – Shows the shutter speeds you need when you open up or stop down the aperture by one stop
• Nearest standard-value guidance – Pairs the calculated result with the closest standard shutter and aperture values
• Scene guide – Explains whether the calculated EV is closer to bright daylight, indoor lighting, or a night street scene

How to use it

Choose what you want to solve for first, then enter the other two values. Because the result updates immediately, you can compare the result card with the equivalent-EV table and adjust on the spot.

1. Choose a mode – Pick EV, shutter, or aperture depending on what you need to solve for.
2. Enter the other two values – Use the f-number for aperture, seconds for shutter speed, and ISO-100 EV for the EV field.
3. Read the result – Start with the top result card to see the solved value and the formula behind it.
4. Compare to standard values – Check the nearest standard aperture and shutter settings so you can move directly to camera controls.
5. Review the equivalent-EV table – Pick a different combination with the same brightness to match the depth of field or motion look you want.

Formula and interpretation notes

At ISO 100, the EV formula is EV = log₂(N² / t). Here N is the aperture value (f-number), and t is the shutter speed in seconds. Keeping the same EV means keeping scene brightness the same while changing only the aperture-and-shutter combination.

To solve for shutter speed, rearrange the formula to t = N² / 2^EV. To solve for aperture, use N = √(t × 2^EV). For example, if you want to shoot at EV 12 with f/8, you need a shutter speed around 1/60 second rather than 1/125 second. If you want an even faster shutter, you have to open the aperture more to hold the same EV.

Common settings such as f/5.6 and 1/125 second are rounded working values rather than perfect logarithmic steps. Because of that, the calculated EV and the standard EV can differ by about 0.1, and this tool shows the nearest standard-value approximation alongside the math.

• Around EV 15 – Very bright scenes such as clear midday daylight outdoors
• Around EV 11–12 – Overcast outdoor light, window light, or a bright room
• Around EV 8 – Typical indoor lighting
• EV 3 and below – Night scenes, dim interiors, or other conditions that often need longer exposures

Frequently asked questions