Paper Size Converter
Compare common paper sizes and convert their dimensions between millimeters and inches.
How to Use the Paper Size Converter
Select a paper format to compare dimensions across A-series, Letter, Legal and other common standards.
Practical Example
A4 paper measures 210 × 297 mm, while US Letter measures 8.5 × 11 inches.
Factors That Affect the Result
Paper standards differ by region, and printer margins, scaling and orientation can affect the usable area even when the physical sheet size is fixed.
Frequently Asked Questions
Is A4 the same as Letter?
No. Their dimensions and aspect ratios differ.
What standard uses A4?
A4 is part of the ISO 216 A-series system.
Does orientation change paper size?
No. Portrait and landscape only change how the same sheet is oriented.
Understanding Paper Size Conversions
Paper formats such as A4, Letter and Legal use different standard dimensions. Converting between millimetres, centimetres and inches helps compare physical page sizes, but changing units does not make two different standards equivalent.
For printing or layout work, check both width and height as well as orientation. Printer margins, bleed and scaling settings can affect the usable area even when the nominal paper size is correct.
Conversion Method and Practical Limits
Paper standards define physical dimensions rather than just names. ISO A-series sizes preserve a √2 aspect ratio, while North American Letter and Legal use different proportions, so scaling documents between standards can introduce margins or cropping.