Work out crop factor instantly with clear inputs, formula shown and shareable results.
Crop factor is the 43.267 mm full frame diagonal divided by the sensor's own diagonal, which follows from Pythagoras on the sensor dimensions. The area ratio matters more than the crop factor for light gathering, since a 1.5x crop sensor has only 44% of the full frame surface area.
Sensor diagonal
diagonal = sqrt(width^2 + height^2)
Crop factor
crop = 43.267 / sensor diagonal
diagonal = sqrt(width^2 + height^2). Crop factor is the 43.267 mm full frame diagonal divided by the sensor's own diagonal, which follows from Pythagoras on the sensor dimensions.
The area ratio matters more than the crop factor for light gathering, since a 1.5x crop sensor has only 44% of the full frame surface area.
Enter sensor width, sensor height. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.