Equivalent Aperture Calculator
When you compare lenses across different sensor sizes, the f-number alone can mislead you, because a smaller sensor needs a wider lens to frame the same shot and that changes the depth of field. This calculator multiplies your aperture by the crop factor to give the full frame equivalent aperture, which is the fair way to compare how blurry a background will be and how much total light the sensor collects. An f/1.8 lens on a Micro Four Thirds body with a 2x factor renders depth of field and gathers total light like an f/3.6 lens on full frame, even though it still exposes at f/1.8. This matters when you shop for fast primes or judge whether a small camera can match a bigger one for portraits. All math runs in your browser and nothing you type leaves your device.
How to use Equivalent Aperture Calculator
- Enter the lens aperture as an f-number.
- Select the sensor size or crop factor.
- Read the full frame equivalent aperture.
- Use it to compare lenses across formats.
Frequently asked questions
What is equivalent aperture?
It is the aperture multiplied by the crop factor to compare depth of field and total light gathering across sensor sizes on an equal footing, so f/2 on APS-C behaves like about f/3 on full frame for depth of field.
Does equivalence change exposure?
No, the f-number that sets brightness stays the same. Equivalence only concerns depth of field and total light collected, which affect noise, not per pixel exposure.
Why compare lenses this way?
It lets you fairly judge a small sensor fast lens against a larger sensor lens, since the raw f-number alone hides the sensor size effect on background blur.
What is Equivalent Aperture Calculator?
When you compare lenses across different sensor sizes, the f-number alone can mislead you, because a smaller sensor needs a wider lens to frame the same shot and that changes the depth of field. This calculator multiplies your aperture by the crop factor to give the full frame equivalent aperture, which is the fair way to compare how blurry a background will be and how much total light the sensor collects.
Is Equivalent Aperture Calculator free to use?
Yes. Equivalent Aperture Calculator is completely free, with no sign-up and no usage limits.
Does Equivalent Aperture Calculator work in a web browser?
Yes. Equivalent Aperture Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Equivalent Aperture Calculator?
Yes. Equivalent Aperture Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
Badge
Link this tool from a README, doc or site. The badge links back to this page.
[](https://yourhack.ai/equivalent-aperture-calculator)