Crop factor calculator
Enter your sensor width and height (or pick a preset) to find its crop factor relative to a 35mm full-frame camera - and instantly see what any lens becomes in full-frame terms.
Your sensor
Choosing a preset fills the dimensions below. Choose “Custom” to type your own width and height.
Used to show what this lens is equivalent to on a full-frame body.
Crop factor is measured on the sensor diagonal, which is how lens specs are quoted.
Result
Crop factor relative to full frame
How crop factor works
Crop factor compares the diagonal of your camera’s sensor with the diagonal of a 35mm full-frame sensor (36 × 24 mm, which is 43.27 mm). A smaller sensor has a larger crop factor because it captures a narrower slice of the lens’s image circle.
Using the diagonal keeps the comparison consistent regardless of whether you shoot horizontal, vertical or square compositions.
Common values
- Full frame / 35mm (36 × 24 mm): 1.00×
- APS-C Canon (22.3 × 14.9 mm): 1.62× (usually quoted 1.6×)
- APS-C Nikon / Sony / Fuji (23.5 × 15.6 mm): 1.53× (usually quoted 1.5×)
- Micro Four Thirds (17.3 × 13 mm): 2.00×
- 1-inch (13.2 × 8.8 mm): 2.72×
Example
On a Canon APS-C body the sensor is 22.3 × 14.9 mm, so the crop factor is 43.27 ÷ 26.82 = 1.61×. Mount a 50mm lens and it frames like a 80.7mm lens would on full frame.
What can you use it for?
- Choosing lenses that give the same framing you are used to on a different sensor size.
- Understanding why your 50mm lens feels “zoomed in” on a crop body.
- Predicting minimum handheld shutter speeds (the reciprocal rule uses focal length × crop factor).
- Comparing depth-of-field behaviour between sensor sizes at the same aperture.
Frequently asked questions
What is crop factor?
Crop factor is the ratio of the diagonal of a 35mm full-frame sensor (36 × 24 mm, diagonal 43.27 mm) to the diagonal of your camera's sensor. It describes how much narrower your field of view is compared with a full-frame camera using the same focal length.
What is the crop factor of APS-C?
APS-C Canon (22.3 × 14.9 mm) has a crop factor of about 1.62×. APS-C Nikon/Sony/Fuji (23.5 × 15.6 mm) is about 1.53× - usually quoted as 1.5×.
Does crop factor change my lens?
No. A 50mm lens is physically still 50mm. Crop factor only changes the field of view you capture: on a 1.5× APS-C camera a 50mm lens frames like a 75mm lens would on full frame.
What is the crop factor of Micro Four Thirds?
Micro Four Thirds (17.3 × 13 mm) has a 2× crop factor, so a 25mm lens frames like a 50mm lens on full frame.