Convert millimeters to pixels instantly
Use this mm to px converter for design, print, image editing, and screen planning. Enter a length in millimeters and your target DPI (pixels per inch).
What this mm to pixels calculator does
This tool converts a physical measurement in millimeters (mm) to a digital measurement in pixels (px). The conversion depends on your DPI value. Without DPI, there is no single fixed answer because pixels are tied to resolution.
If you're creating graphics for web pages, preparing print-ready files, or matching dimensions between design software and real-world sizes, this calculator gives you fast, accurate results.
mm to px formula
The conversion formula is straightforward:
pixels = millimeters × (DPI ÷ 25.4)
Why 25.4? Because one inch equals exactly 25.4 mm, and DPI means dots (or pixels) per inch.
Manual example
- Given: 50 mm at 300 DPI
- Step 1: 300 ÷ 25.4 = 11.811...
- Step 2: 50 × 11.811... = 590.55 px
- Rounded: 591 px (if rounding to a whole number)
Common DPI settings and when to use them
- 72 DPI: legacy screen workflows and rough previews.
- 96 DPI: common CSS/reference screen density baseline.
- 150 DPI: low-to-mid quality print drafts.
- 300 DPI: standard high-quality print output.
- 600 DPI: detailed line art, technical diagrams, and specialized print work.
Quick reference table (at 96 DPI)
| Millimeters (mm) | Pixels (px) at 96 DPI |
|---|---|
| 1 mm | 3.78 px |
| 5 mm | 18.90 px |
| 10 mm | 37.80 px |
| 25.4 mm | 96 px |
| 50 mm | 188.98 px |
| 100 mm | 377.95 px |
Where mm-to-pixel conversion is useful
1) UI and product design
When you move between spec sheets (often in mm) and screen mockups (px), conversion helps maintain proportions and spacing consistency.
2) Print and packaging
Print templates are usually dimensioned physically (mm/inches), while artwork is rendered in pixels. Accurate conversion prevents blurry output and wrong print scale.
3) Photography and image editing
If you know the target print size in millimeters and desired print DPI, you can compute exactly how many pixels your source image needs.
Tips for accurate conversion
- Always confirm your target DPI before exporting.
- Keep extra pixels for crop/bleed in print workflows.
- Use decimal precision during planning, then round at export time.
- For width and height conversions, calculate each side independently using the same DPI.
FAQ
Is 96 DPI always correct for web?
Not always. 96 DPI is a useful reference, but modern displays vary in pixel density. For CSS layouts, think in CSS pixels; for image exports, choose sizes that look sharp on your target devices.
Why does my print result look different than expected?
Most mismatches come from incorrect DPI settings, scaling during print, or export compression. Make sure document size, pixel dimensions, and print settings all align.
Can I convert pixels back to mm?
Yes. Reverse the formula: mm = pixels × 25.4 ÷ DPI. Use the same DPI used during your original design or output process.
Use the calculator above anytime you need a fast, reliable millimeter-to-pixel conversion.