Resize Image to A3
Place artwork, a poster, diagram, scan, or photograph on an A3 297 x 420 mm canvas with practical print margins.
A3 proportions with controlled printer margins
297 x 420 mm proportions
Create standard A3 geometry in portrait or landscape orientation.
150 or 300 DPI calculation
Generate approximately 1754 x 2480 or 3508 x 4961 portrait pixels.
Millimeter margin control
Reserve whitespace for office printers, frames, binding, or document layouts.
A3 raster dimensions
| Setting | Result | Best use |
|---|---|---|
| 150 DPI | 1754 x 2480 px | Drafts and lighter poster files |
| 300 DPI | 3508 x 4961 px | Detailed print calculation |
| 12 mm margin | Practical starting clearance | Useful for many non-borderless printers |
| 0 mm margin | Full-bleed image canvas | Requires compatible printer or added bleed |
How it works
- 1
Upload an image
Choose a poster, artwork, scan, chart, or photo.
- 2
Configure A3 output
Select DPI, orientation, margins, background, and fit mode.
- 3
Download and print
Export JPG or PNG and choose A3 paper in the print dialog.
A3 dimensions, pixels, and printing
A3 paper measures 297 x 420 millimeters and is twice the area of A4. Common rounded pixel dimensions are 1754 x 2480 at 150 DPI and 3508 x 4961 at 300 DPI in portrait orientation.
Large high-DPI canvases consume significant memory, especially on mobile devices. Use 150 DPI for drafts or distance-viewed posters when appropriate. Browser export may omit density metadata, so select A3 paper and verify scaling in the print dialog.
Frequently asked questions
What pixel dimensions are A3 at 300 DPI?
A commonly used rounded size is 3508 x 4961 pixels in portrait orientation.
What size is A3 in millimeters?
A3 measures 297 x 420 mm.
Is A3 twice the size of A4?
A3 has twice the area of A4.
Why add margins?
Many printers cannot print to the page edge, and frames or binding may cover outer content.
Resize Image to A3 last reviewed: Aug 2, 2026.