Open calculation methods
How accurate are these numbers?
Calculated values support comparisons; they do not replace laboratory tests. Here are each metric's sources, assumptions, and error bounds.
Method version 1.0 · reviewed 2026-08-14
Diagonal
√(width² + height²)
Input: Sensor width and height
Surface area
width × height
Input: Sensor width and height
Crop factor
43.27 ÷ sensor diagonal
Input: 35mm film diagonal
Pixel pitch
sensor width ÷ horizontal pixels × 1000
Input: Dimensions and effective pixels
Pixel area
pixel pitch²
Input: Theoretical square pixels
Pixel density
effective pixels ÷ sensor area
Input: Effective pixels and area
Relatively reliable data
Sensor width and height published in millimeters are generally accurate, with only small errors from manufacturer rounding.
Data to treat as estimates
1/N-inch sensors, manufacturer pixel counts, and pixel area all involve estimation. Pixel pitch is usually within about 2% error.
Calculation basis
All derived metrics use only sensor dimensions and effective pixels. When both total and effective pixels are provided, we use effective pixels because they better represent the active imaging area.
Pixel assumptions
The formulas assume gapless square pixels. Real sensors may have gaps, different arrangements, and microlens structures, so pixel area represents a theoretical upper bound.
Comparison principles
Never judge image quality from one number. Consider sensor area, pixel pitch, readout speed, processor, lens, and release date together.
Example: Canon EOS R7 crop factor
Using the 22.3 × 14.9 mm sensor dimensions, first calculate the diagonal and then divide the 43.27 mm diagonal of the 35mm frame by that result. Rounded to two decimals, the crop factor is about 1.61×.
√(22.3² + 14.9²) = 26.82 mm · 43.27 ÷ 26.82 = 1.61×