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A3 Size Calculator

Plan A3 posters, proofs and large document images by converting A3 physical size into pixels at your chosen DPI.

A3 297 x 420 mmDPI to pixelsPoster planningLocal calculation

A3 size calculator

Selected images stay in your browser. The calculator only reads pixel dimensions.

Result

Print size
297 x 420 Millimeters
Pixel size
3508 x 4961 px
ISO A3 paper size for posters, proofs and large layouts.

Print quality: High-quality print

How it works

  1. 1Use the A3 preset.
  2. 2Enter the DPI needed for print or export.
  3. 3Use the pixel result before resizing or preparing artwork.

Privacy and limits

  • The result is based on standard A3 size and selected DPI.
  • Large prints may need bleed, margins or printer-specific setup.
  • The calculator does not upload images.

A3 pixel calculation notes

A3 is 297 x 420 mm and is commonly used for posters, proofs and larger document layouts.

The calculator gives the pixel target for the DPI you choose.

Common use cases

  • Preparing A3 poster artwork
  • Checking large scan dimensions
  • Planning print-ready document images

Print notes

  • A3 at 300 DPI is about 3508 x 4961 pixels.
  • Large prints may look acceptable at lower DPI when viewed from farther away.
  • Printer bleed and margins are separate layout settings.

Original test sample

  • Set A3 to 300 DPI and confirm the result is about 3508 x 4961 pixels.
  • Use 150 DPI to estimate a lighter preview export.

Frequently asked questions

Are my images uploaded?

No. ImgShrink processes selected images in your browser and does not upload them to a server.

Which DPI should I use?

300 DPI is a common high-quality print target, 150 DPI can work for general print, and 72 or 96 DPI is mainly screen-oriented.

Is this a final print or document approval check?

No. The calculator gives pixel, DPI and physical-size math. Printers, passport offices and upload portals may apply extra rules.

Source and compatibility notes

DPI and print-size results use standard pixel-to-physical-size formulas. Document-photo presets are reference sizes, not a substitute for official submission rules.

Last checked: 2026-09-07

Notes
  • Formula: inches = pixels / DPI; centimeters = inches x 2.54.
  • Passport and document photo rules vary by country and use case.
  • Verify official instructions before submitting ID or visa photos.

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