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Paper Size Converter Calculator

Work out paper size converter instantly with clear inputs, formula shown and shareable results.

About Paper Size Converter Calculator

The ISO A series is built so each size is half the previous one with the same 1:sqrt2 aspect ratio, starting from A0 at one square metre. A4 is 210 by 297 mm, which at 300 dpi is 2480 by 3508 pixels - the standard print-ready canvas size. US Letter breaks the pattern entirely at 215.9 by 279.4 mm.

Formulas

A series

each size halves the previous, aspect ratio 1:sqrt(2), A0 = 1 m2

Pixel dimensions

pixels = size in inches x dpi

Worked example

With the default values below, Paper Size Converter Calculator returns Width of 210.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Paper sizeone of A0, A1, A2, A3, A4, A5, A6, US Letter, US Legal, Tabloid
A4
Print resolutionminimum 1 dpi
300 dpi

Results

Width
210.0 mm
Height
297.0 mm
Pixel Dimensions At That Resolution
2480 x 3508 px
Sheet Area
0.0624 m2

Step by step

  1. 1Values used
  2. 2A series
  3. 3Pixel dimensions
  4. 4Width= 210.0 mm
  5. 5Height= 297.0 mm
  6. 6Pixel Dimensions At That Resolution= 2480 x 3508 px
  7. 7Sheet Area= 0.0624 m2

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why is the aspect ratio 1:sqrt2?

Because it is the only ratio preserved when a sheet is halved, so scaling between A sizes never changes the proportions.

What resolution do I need for print?

300 dpi for photographic quality, 150 dpi for large posters viewed at distance, and 600 dpi or more for fine line art.

Related Calculators

Paper Size Converter Calculator – Calculate Width & Height