Resize Image to A3 Size
A3 is 29.7 x 42 cm, twice the size of A4, used for posters, drawings and charts. Fit any photo or scan to it at 300 DPI, ready to print.
A3 · Step 1 of 3 · Add your photo
Drop an image to resize
or paste with Ctrl+V · JPG PNG WebP HEIC GIF · max 25 MB
Processed on this device. Nothing is uploaded.
Example
Before and after
We ran this sample through the a3 tool above. The numbers under each image are measured from the real files.
How to
How to resize an image to A3 size
- 1.
Add your image. A scan, a screenshot, a design or a photo of a document.
- 2.
Choose fit or fill. Fit keeps the whole image on the page with white margins. Fill covers the page and trims the edges.
- 3.
Download and print. Print at 100% scale (actual size) and you get exactly 29.7 x 42 cm.
Why this size
A3 size in pixels, cm and inches
Printers think in physical sizes, screens think in pixels. A3 is 29.7 x 42 cm, or 11.69 x 16.54 in. At 300 DPI, the standard for sharp prints, that is 3508 x 4961 px; at 150 DPI, enough for posters seen from a distance, it is 1754 x 2480 px.
The tool resizes your image to the 300 DPI size and writes 300 DPI into the file, so print dialogs pick the right size automatically. Print at 100% or Actual size, not Fit to page, and the result measures exactly 29.7 x 42 cm.
| Measure | A3 |
|---|---|
| Centimeters | 29.7 x 42 cm |
| Inches | 11.69 x 16.54 in |
| Pixels at 300 DPI | 3508 x 4961 px |
| Pixels at 150 DPI | 1754 x 2480 px |
| Pixels at 72 DPI | 842 x 1191 px |
| Aspect ratio | 1:1.41 |
Avoid
Common problems and fixes
- The print comes out smaller, with wide white bordersThe print dialog is set to Fit to page. Choose 100% or Actual size and the page prints at the real size.
- The edges are cut offMost printers cannot print the last 3 to 5 mm of a sheet. Choose Fit when you resize, so the whole image sits inside the A3 page with a margin.
- The print looks blurryThe image has too few pixels for the size. Compare its width with the 300 DPI size in the table above; a smaller original prints soft however you resize it.
- My printer cannot print A3Most home printers stop at A4. Take the file to a print shop, which prints A3 from the same 300 DPI file.
FAQ
A3: questions
Checked
How we checked this page
Checked by the SizePort team on .
We test the tool with sample photos before it goes live and check that the sizes on this page match what it produces. Rules and platforms change, so if something here is out of date, tell us and we will correct it.
How the tool works
The tool scales your image once, from the original pixels, to the size you set at 300 DPI, and writes 300 DPI into the file so it prints at that size. Everything happens in your browser; your images are never uploaded.