Camera Sensor Size Calculator (1/1.3″, 1″ …)

Understanding the camera sensor size calculator — concept and principle

Phone and compact-camera sensors are named with odd fractions such as 1/1.3″, 1/2.3″ or 1″. This calculator turns that "1/x inch" type into an approximate width, height, diagonal, area and crop factor, so you can compare a phone sensor with APS-C or full frame and estimate how much light it collects.

Both rectangles are drawn at the same scale (36 × 24 mm vs 9.85 × 7.38 mm).

How it is calculated

For common published types from 1/3.2″ to 1″ (for example 1/2.3″ = 6.17 × 4.55 mm, 1″ = 13.2 × 8.8 mm) the calculator uses a lookup table of standard dimensions. For any other type 1/x″ it estimates:

Diagonal d = k ÷ x (mm), with k = 16 mm per "inch" for types up to 1/2″, rising gradually to about 18 mm for 1/2.3″ and smaller
Width = 0.8 × d, height = 0.6 × d, assuming a 4:3 sensor (the 3-4-5 triangle)
Area = width × height (mm²)
Share of full frame = area ÷ 864 mm² (36 × 24 mm)
Crop factor = 43.27 ÷ d, where 43.27 mm is the full-frame diagonal

The principle

The inch names come from television camera tubes of the mid-20th century. A tube's outer glass diameter was quoted in inches, but the light-sensitive area inside was only about two thirds of that, so a "1-inch" tube imaged a diagonal near 16 mm. Sensor makers kept the naming, which is why a 1″ sensor is about 13.2 × 8.8 mm rather than 25.4 mm across. Crop factor compares diagonals: with the same lens angle of view, a smaller sensor sees a narrower slice of the image circle.

Worked example

Default: type 1/1.3″, so x = 1.3; it is not in the table, so the 16 mm rule applies.

Diagonal: 16 ÷ 1.3 = 12.31 mm.
Width: 0.8 × 12.31 = 9.85 mm; height: 0.6 × 12.31 = 7.38 mm (shown rounded as 9.8 × 7.4 mm).
Area: 9.85 × 7.38 = 72.7 mm².
Versus full frame: 72.7 ÷ 864 = 8.4%.
Crop factor: 43.27 ÷ 12.31 = 3.52.

How to read the result

A larger area collects more light at the same f-number and shutter speed, which usually means less noise and more dynamic range. As a rough ladder: full frame 864 mm², APS-C about 330–370 mm², Micro Four Thirds about 225 mm², 1″ about 116 mm², 1/1.3″ about 73 mm². A sensor with crop factor 3.52 needs a lens about 3.52 times shorter than full frame for the same view; a 6.8 mm lens on it frames like about 24 mm.

Common mistakes

Reading 1/1.3″ as 1/1.3 of 25.4 mm (19.5 mm); the real diagonal is near 12.3 mm.
Ignoring aspect ratio: a 16:9 or 3:2 chip of the same type has a different width and height.
Comparing megapixels alone; pixel size depends on both sensor area and resolution.

Keep in mind: The table holds typical published sizes and the formula is only an approximation: small types tend to be larger than 16 ÷ x predicts, and each chip differs (some are 16:9 or crop the active area). Check the maker's datasheet for exact dimensions.

FAQ

Frequently asked questions

How big is a 1-inch sensor?

Typically about 13.2 × 8.8 mm (3:2), diagonal about 15.9 mm, crop factor about 2.7.

Is 1/1.3″ bigger than 1/2.3″?

Yes. A smaller x means a bigger sensor; 1/1.3″ (72.7 mm²) has about 2.6 times the area of 1/2.3″ (28.1 mm²).

Why does crop factor use the diagonal?

It makes sensors with different aspect ratios comparable by angle of view along the diagonal.

Sources: Manufacturer image sensor datasheets (e.g. Sony Semiconductor Solutions)

Size charts differ between brands and countries — treat this as a starting point and check the maker’s own chart.

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