Sunny 16 Rule Calculator
Fill in the values and the answer updates as you type.
How the Sunny 16 Rule Calculator works
On a sunny day, f/16 with a shutter speed of 1 ÷ ISO gives a good exposure. Each step darker in the lighting list opens up one more stop, from f/16 to f/11, f/8, f/5.6, and f/4. The tool then shifts the time to match the aperture you choose. It is a reliable backup for film cameras and when the meter fails. Example: At f/8 and ISO 100 in full sun, use about 1/400 s.
Inputs and results
The Sunny 16 Rule Calculator takes 3 inputs and gives 3 results.
What you enter
- Aperture (f-number) (f/) — starts at 8.
- ISO — starts at 100.
- Lighting — starts at Sunny (hard shadows). Choose from: Sunny (hard shadows), Slightly overcast (soft shadows), Overcast (faint shadows), Heavy overcast (no shadows) and Open shade or sunset.
What you get
- Suggested shutter speed
- Shutter time (seconds)
- Exposure value at ISO 100 (EV)
Example: Sunny 16 Rule Calculator with the starting values
With aperture (f-number) 8 f/, iso 100 and lighting Sunny (hard shadows), the calculator returns:
| Suggested shutter speed | 1/400 s |
|---|---|
| Shutter time (seconds) | 0.0025 |
| Exposure value at ISO 100 (EV) | 14.6 |
Change any value above and the results update straight away.
Sunny 16 Rule Calculator FAQ
How do I use the Sunny 16 Rule Calculator?
Enter aperture (f-number), iso and lighting in the fields, then read suggested shutter speed, shutter time (seconds) and exposure value at iso 100 (ev) 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 Sunny 16 Rule Calculator calculate?
Estimate exposure outdoors without a light meter. It returns suggested shutter speed, shutter time (seconds) and exposure value at iso 100 (ev) from the 3 values you provide.
What values does the Sunny 16 Rule Calculator start with?
It opens with aperture (f-number) 8 f/, iso 100 and lighting Sunny (hard shadows) 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 Sunny 16 Rule 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 Sunny 16 Rule 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.