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Paper Sizes Calculator

Compare paper sizes and convert millimetres, inches and DPI pixels.

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What this tool does

A quick reference for every common paper size — ISO A-series, B-series, US Letter / Legal / Tabloid, and standard photo prints. Pick a size to see its dimensions in mm and inches, convert any custom size, and calculate the pixel dimensions you need to print at a target DPI.

Size lookup

Standard paper sizes

Category

Millimetres

210 mm × 297 mm

Inches

8.27 in × 11.69 in

Custom converter

mm ↔ inches and pixels at DPI

Inches

8.27 in × 11.69 in

Pixels at 300 DPI

2480 × 3508 px

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Paper sizes made simple

Pick a standard size or enter a custom size to convert between millimetres and inches. Then add a DPI value to see the exact pixel dimensions you need for crisp, print-ready files. If you already have pixels and want DPI, use the DPI Calculator.

What is included

  • ISO A-series (A0–A10)
  • ISO B-series
  • US Letter, Legal, and Tabloid
  • Common photo print sizes
  • Custom size input with mm/inch conversion
  • DPI to pixels calculator

When to use each size

  • A4: most common worldwide for documents, planners, and worksheets.
  • US Letter: standard in the United States for home and office printing.
  • Legal/Tabloid: contracts, reports, and larger layouts.
  • Photo sizes: prints, albums, and framed images.

How to use it

  1. Pick a preset size or type your own dimensions.
  2. Switch units between mm and inches as needed.
  3. Enter a target DPI (commonly 300 for photos, 150 for posters).
  4. Read off the pixel dimensions you need for that print size at the chosen DPI.

Helpful tips

  • The ratio of every A-series size is 1:√2, so doubling a sheet gives you the next size up.
  • Use 300 DPI as a baseline for sharp photo prints, and lower DPI for posters viewed at a distance.
  • For framed photos, 4R (4 × 6 in), 5R (5 × 7 in), and 8R (8 × 10 in) are the most common print sizes.

FAQs

Quick answers

Which paper sizes are included?

The calculator includes ISO A0–A10, ISO B-series sizes, US Letter/Legal/Tabloid, and common photo sizes.

Can I convert between mm and inches?

Yes. Enter a custom size in millimetres to see the matching inches instantly.

Does this calculator include DPI?

Yes. Enter your DPI to see the pixel dimensions needed for a given print size.

What's the difference between A4 and Letter?

A4 is 210 × 297 mm (8.27 × 11.69 in) and is standard in most countries. US Letter is 8.5 × 11 in and is common in the United States.

What is the difference between A-series and B-series?

A-series sizes (A0–A10) are based on a 1:√2 aspect ratio and an A0 area of 1 m². B-series sizes are slightly larger than the matching A-size and used for posters, books, and envelopes.

What is the most common photo print size?

In most regions, 4R (4 × 6 inches / 102 × 152 mm) is the standard photo print size. 5R (5 × 7 in) and 8R (8 × 10 in) are common for framed photos and portraits.

Is this printable only?

No. This tool is a calculator and reference; it does not generate PDFs.

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