SizeKit

SizeKit reference

Unit Converter

Convert mm, cm, inches, pixels, and points with DPI-aware pixel conversion.

Physical units convert directly through inches. Pixels need a DPI value before they can be converted to physical size.

SizeKit

Common results first

These cover frequent one-off checks. Use the full calculator below only for custom values.

ISO A A4 210 x 297 mm 2480 x 3508 px at 300 DPI Open North America US Letter 215.9 x 279.4 mm 2550 x 3300 px at 300 DPI Open Print 2480 x 3508 px 8.27 x 11.69 in at 300 DPI Customize Ratio 1920 x 1080 16:9 common video / screen ratio Customize

SizeKit

Custom calculator paths

Use these only when the default answers are not enough.

SizeKit

Full custom calculator

Keep this for users who need to adjust exact values.

SizeKit

Formula

The formula is here for checking the answer, not as the main workflow.

SizeKit calculations run in your browser and use shared conversion formulas.

SizeKit

Related paths

Use a reference page if you know the size name; use a calculator only when your value is custom.

A4

A4 size page

Get mm, inches, and common pixel presets without configuring anything.
PAPER

All paper sizes

Browse by name, country, and use case.
SOC

Social and web sizes

Find recommended export dimensions.

SizeKit

FAQ

Practical calculator questions.

Do I need DPI for pixel conversion?

Yes. Pixels only become a physical size when you choose DPI or PPI.

Can I copy the result?

Yes. Each calculator result includes a copy button.