A full-frame equivalent focal length and aperture calculator for photographers.
The original mmcalc.com was a beautifully simple tool that I used all the time. Sensor crop factor math isn't hard, but having a dedicated calculator for it was just nice. Then one day it was gone. No warning, no archive, just gone.
I loved that site. And after years of muscle memory typing mmcalc into my browser, I couldn't be bothered to remember any other URL. So I built my own.
This is my love letter to the original mmcalc.com. If you ran it and you're reading this: thank you, it was great.
- Full-frame equivalent focal length and aperture calculation
- Side-by-side comparison of multiple sensor formats
- Depth of field calculator (near limit, far limit, total DoF)
- Shareable URLs: every calculator state is encoded in the query string
- Dark mode
- Works from the terminal
No browser needed. Just curl it:
$ curl mmcalc.com/gfx-80-1.7
FF Equivalent: 122mm f/2.6
Crop Factor: 1.53xThe URL pattern is /<sensor>-<focal_length>-<aperture>.
| ID | Format |
|---|---|
ff |
Full Frame (36x24mm) |
apsc |
APS-C (23.5x15.6mm) |
apsc-canon |
APS-C Canon (22.3x14.9mm) |
apsh |
APS-H (27.9x18.6mm) |
mft |
Micro Four Thirds (17.3x13mm) |
1inch |
1-inch (13.2x8.8mm) |
gfx |
Fujifilm GFX (43.8x32.9mm) |
hasselblad |
Hasselblad X (43.8x32.9mm) |
phaseone |
Phase One (53.4x40mm) |
pentax645d |
Pentax 645D/Z (43.8x32.8mm) |
645 |
645 Film (56x42mm) |
6x6 |
6x6 Film (56x56mm) |
6x7 |
6x7 Film (56x69mm) |
6x9 |
6x9 Film (56x83mm) |
4x5 |
4x5 inch (100x120mm) |
8x10 |
8x10 inch (195x246mm) |
Tool versions are managed with mise:
mise install # installs node 22 + bun
bun install # install dependencies
bun run dev # start dev server
bun run build # type-check + production build
bun run lint # eslintMIT