๐ Unit Conversion
Paper Size Calculator
The ISO A series halves in area at every step while keeping the same aspect ratio of one to the square root of two, which is why a folded A4 is exactly A5. US sizes follow different proportions.
How it works
Paper size
Width
Height
Area
Width
Height
Frequently asked questions
How do I use the Paper Size Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.