MM to PX Converter
Convert mm, cm and inches to pixels at any DPI, with ISO and US paper size presets, bleed and safe margin — all calculated instantly in your browser.
Unit converter
Paper size
Bleed & safe margin
- Trim size210.00 × 297.00 mm · 2480 × 3508 px
- With bleed216.00 × 303.00 mm · 2551 × 3579 px
- Safe area204.00 × 291.00 mm · 2409 × 3437 px
Everything runs locally in your browser. Nothing is uploaded to any server — close the tab and your files are gone.
Common sizes cheat sheet
A4 (210 × 297 mm) at the print and screen resolutions you’ll actually run into:
| DPI | Pixels (px) |
|---|---|
| 72 | 595 × 842 |
| 150 | 1240 × 1754 |
| 300 | 2480 × 3508 |
Which DPI should I use?
- 72 DPI — legacy screen resolution (pre-Retina displays)
- 96 DPI — the CSS reference pixel used by browsers and UI design
- 150 DPI — draft-quality print, quick proofs
- 300 DPI — standard for print production (brochures, magazines)
- 600 DPI — fine art prints and large-format signage
How to use
Type a size
Enter a value into any row — mm, cm, inch or px — and the other three update instantly.
Set the DPI
Pick a preset (72 / 96 / 150 / 300 / 600) or type a custom value from 1 to 2400. Pixel values recalculate live as you change it.
Choose a paper size
Select an ISO A or B size, US Letter, Legal or Tabloid, or a business card, credit card or postcard preset, then toggle portrait or landscape.
Add bleed and safe margin
Set bleed and safe margin in mm to see the trim size, the size with bleed, and the safe area in both mm and px.
Frequently asked questions
What is A4 in pixels at 300 DPI?
A4 is 210 × 297 mm. At the print standard of 300 DPI that’s 2480 × 3508 px (210 ÷ 25.4 × 300, rounded). At 150 DPI it’s 1240 × 1754 px, and at 72 DPI it’s 595 × 842 px.
Why does CSS use 96 DPI?
Browsers and OS UI frameworks have used 96 DPI (96 px per inch) as the screen pixel reference since the 1990s. CSS defines its px unit against that same 96 DPI baseline, so it’s the number used whenever inches or points are converted to px.
What is bleed, and why is 3 mm the default?
Bleed is extra artwork drawn past the trim line so a small misalignment when a printer cuts the sheet doesn’t leave a white edge. 3 mm is a common print-shop default, but always confirm the exact figure your printer requires before sending final files.
What’s the difference between DPI and PPI?
Strictly, DPI (dots per inch) describes a printer’s ink-dot density, while PPI (pixels per inch) describes a digital image’s pixel density. Design tools often use the terms interchangeably — this tool uses DPI since that’s the more familiar term for print work.
Why is my exported image too small to print?
Exporting at the screen default of 72 DPI produces far fewer pixels than 300 DPI for the same physical size, since px = mm ÷ 25.4 × DPI. Check the pixel size at your target DPI here before exporting.
What’s the difference between safe margin and bleed?
Bleed extends artwork outward past the trim line; safe margin pulls inward from it as a keep-out zone for text and logos. Both use the same math — grow or shrink every side by the same amount — just in opposite directions.