Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Optics
F-Number Calculator
Compute the f-number (f-stop) of a lens by dividing its focal length by the aperture diameter. Use it when selecting lenses, comparing lens speed, or setting exposure in photography.
Fill in the required fields to see your result.
Optics
Focal Length Calculator
Find the focal length of a lens given the distance to the object and the distance to the formed image. Essential for photographers, opticians, and physics students working with thin-lens optics.
Fill in the required fields to see your result.
Key differences
| F-Number Calculator | Focal Length Calculator | |
|---|---|---|
| Category | Optics | Optics |
| Inputs required | 2 | 2 |
| Result | F-Number | Focal Length (cm) |
| What it does | Compute the f-number (f-stop) of a lens by dividing its focal length by the aperture diameter. Use it when selecting lenses, comparing lens speed, or setting exposure in photography. | Find the focal length of a lens given the distance to the object and the distance to the formed image. Essential for photographers, opticians, and physics students working with thin-lens optics. |