C8 at 240 dpi — 539×765 pixels

57×81 mm at 240 dpi comes to 539×765 pixels. On 80 g paper one sheet weighs 0.37 grams.

millimetres: 57 × 81 mm
inches: 2.24 × 3.19 in
Pixels: 539 × 765 px
All the pixels together: 0.41 MP
Uncompressed, that is: 1.2 MB
Area: 0.0046 m²
Ratio of the sides: 1 : 1.421
Sheets in one letter: 67

Weight per sheet

Paper weight is printed as g/m² — grams for one square metre. An A4 is a sixteenth of an A0, so 0.0625 m²; at 80 g that is 5 grams. If a letter must stay under 25 grams, 80 g paper gives you five sheets.

70 g/m²0.32 g
80 g/m²0.37 g
100 g/m²0.46 g
120 g/m²0.55 g
160 g/m²0.74 g
200 g/m²0.92 g
250 g/m²1.15 g
300 g/m²1.39 g

The envelope it fits

C781×114mm

Nearby cells

C7 · 240dpi

765×1077

Same size, other resolutions

How to read this

Dimensions are in millimetres. Leftover fractions are dropped when folding, exactly as the standard says.
Pixel counts are rounded. Printers usually ask for 300 dpi.
The weight is the paper alone. Add the envelope and the ink separately.
Letter and Legal are defined in inches, so folding them does not preserve the √2 ratio.

Frequently asked questions

Q. How big is C8?

57×81 mm, or 2.24×3.19 inches.

Q. How many pixels at 240 dpi?

539×765. That is 0.41 megapixels, or 1.2 MB uncompressed.

Q. What does one sheet weigh?

0.37 g on 80 g paper, 0.55 g on 120 g. A 25 g letter takes 67 of them.

Q. What envelope does it fit?

A C7 envelope, 81×114 mm.