BYTETOOLS

Paper Size Converter

Look up any ISO A, B, C, JIS B, ANSI or photo paper size in mm, cm, inches, points and pixels, and get the exact print scale between any two sizes.

210
A4 width (mm)
297
A4 height (mm)
141.4%
Scale to A3
1 : 1.4143
Aspect ratio

A4 in every unit

UnitWidthHeight
Millimetres210297
Centimetres2129.7
Inches8.26811.693
Points (1/72 in)595.28841.89
Pixels at 300 DPI2,4803,508

Sheet area 0.0624 m². The ratio is 1 : 1.4143, which is √2 to within the millimetre rounding the standard applies — halve the long side and you get the next size down with the same shape.

Printing A4 onto A3

  • Fit-to-page scale: 141.4%
  • Width-only scale: 141.4%
  • Height-only scale: 141.4%
  • Margin-safe fit (10 mm): 131.9%
  • Printable area: 277 × 400 mm

Enter the fit-to-page figure in your printer dialog's custom-scale box. A4 → A3 is 141.4% and A3 → A4 is 70.7%, the two numbers stamped on almost every office photocopier.

Full size table

Sizemminchespointspx @ 300 DPI
A0841 × 1,18933.11 × 46.812,384 × 3,3709933 × 14043
A1594 × 84123.39 × 33.111,684 × 2,3847016 × 9933
A2420 × 59416.54 × 23.391,191 × 1,6844961 × 7016
A3297 × 42011.69 × 16.54842 × 1,1913508 × 4961
A4210 × 2978.27 × 11.69595 × 8422480 × 3508
A5148 × 2105.83 × 8.27420 × 5951748 × 2480
A6105 × 1484.13 × 5.83298 × 4201240 × 1748
A774 × 1052.91 × 4.13210 × 298874 × 1240
A852 × 742.05 × 2.91147 × 210614 × 874
A937 × 521.46 × 2.05105 × 147437 × 614
A1026 × 371.02 × 1.4674 × 105307 × 437

What is the Paper Size Converter?

The ByteTools Paper Size Converter carries the full ISO 216 A, B and C series, the Japanese JIS B series, the North American ANSI and architectural sizes, and the common photo and card sizes.

  • ISO A, ISO B, ISO C, JIS B, ANSI, architectural, photo and card sizes built in
  • Dimensions in mm, cm, inches, points and pixels at any DPI from 1 to 4800
  • Fit-to-page, width-only, height-only and margin-safe print scales
  • Portrait and landscape, with a scaled visual comparison of the two sheets
  • Shows the √2 aspect ratio and the sheet area in square metres
  • Downloadable CSV of any whole series

How to use the Paper Size Converter

  1. 1

    Choose your paper size from the dropdown — the list is grouped by series.

  2. 2

    Pick the size you want to compare with or print onto, and set portrait or landscape.

  3. 3

    Set the resolution in DPI for the pixel dimensions, and a printer margin in millimetres.

  4. 4

    Read the dimensions in every unit and the fit-to-page percentage in the panels.

  5. 5

    Switch the series selector at the bottom to browse a whole series, and download it as CSV.

About the Paper Size Converter

The ByteTools Paper Size Converter carries the full ISO 216 A, B and C series, the Japanese JIS B series, the North American ANSI and architectural sizes, and the common photo and card sizes. Pick one and you get its dimensions in millimetres, centimetres, inches, PostScript points and pixels at whatever resolution you set, along with its aspect ratio and sheet area.

The second half answers the question people actually have: what percentage do I type into the printer dialog? Choose a target size and the tool gives the fit-to-page scale, the width-only and height-only scales, and a margin-safe figure that keeps a border you specify. A4 to A3 comes out at 141.4% and A4 to Letter at 94.1%, the numbers printed on every office photocopier.

All of it is computed in your browser from the published dimensions, so nothing is uploaded and the page keeps working offline. Any whole series can be downloaded as a CSV for your own reference, and a small scaled diagram shows the two sheets on top of each other so you can see at a glance how much bigger or smaller the target really is.

Frequently asked questions

What size is A4 in inches and pixels?

A4 is 210 × 297 mm, which is 8.27 × 11.69 inches, or 595 × 842 PostScript points. At 300 DPI that is 2480 × 3508 pixels, and at 72 DPI it is 595 × 842 pixels. Change the DPI field and the pixel figures update immediately.

What percentage do I use to print A4 on A3?

141.4%, which is √2 rounded to one decimal place. Going the other way, A3 to A4, is 70.7%. Those two numbers work for every step of the ISO A series because each size is exactly half the area of the one above it.

What is the scale from A4 to US Letter?

About 94%, because Letter is 6 mm wider but 18 mm shorter than A4. The height is the limiting dimension, so the fit-to-page scale is 279.4 ÷ 297 = 94.1%. Printing Letter content onto A4 needs about 97% in the other direction.

Why is A4 the size it is?

ISO 216 starts from A0 at exactly one square metre with sides in the ratio 1 : √2. Halving the long side keeps that ratio, so every A size is the same shape as every other. A4 is A0 folded in half four times, and the millimetre figures are the exact values rounded down.

What is the difference between ISO B and JIS B paper?

They are different standards with the same name. ISO B sizes are the geometric mean of the neighbouring A sizes, so B4 is 250 × 353 mm. JIS B sizes are 1.5 times the area of the matching A size, making JIS B4 257 × 364 mm. Both series are listed here separately.

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