Paper Size Calculator: Dimensions for Every Standard Size
Paper sizes are more useful as numbers than as names. A4 is the everyday standard, A3 is twice its area, and Letter is the North American near-equivalent.
What is the Paper Size Calculator?
Choose a paper size and the tool gives its width, height, and area. A-series sizes follow a neat rule: each size is half the previous one, so A4 is half of A3, and the whole series keeps the same shape. Letter and Legal are the common North American sizes.
How to use it
- Choose a paper size.
- Click Show Paper Size.
- Read the dimensions in millimetres and inches, plus the area.
Worked example
A4 paper measures 210 by 297 millimetres, with an area of 623.7 square centimetres.
Why does the A-series keep the same shape?
Because each size is the previous one cut in half across its long side, which preserves the side ratio at every step.
Frequently asked questions
Is Letter the same as A4?
No. Letter is 216 by 279 millimetres, slightly wider and shorter than A4's 210 by 297.
What is Legal paper?
A North American size, 216 by 356 millimetres — the same width as Letter but longer.