LetterFormat.netLetterFormat

Paper Size Converter

Enter paper dimensions to convert between mm, inches, and pixels.

Paper Size Converter
Convert between mm, inches, and pixels
Enter dimensions to see results
Enter dimensions to see results
Enter dimensions to see results

1 inch = 25.4 mm

Pixels calculated as inches × DPI

Tools

Accurate, Fast, and Print‑Ready Conversions

Everything you need to convert paper sizes across units with professional precision for design, print, and digital output.

Unit Conversion

Convert between millimeters, inches, and pixels with precise rounding.

DPI Aware

Preview pixel dimensions at 72/96/150/300/600 DPI instantly.

Aspect Ratio Lock

Keep proportions when adjusting one side to avoid distortions.

Copy Friendly

One‑click copy for mm, inches, and pixel outputs for reuse.

Global Units

Metric and imperial support for international teams and printers.

SEO‑Ready Content

Detailed guidance that helps your team choose the right settings.

FAQ

Conversion Tools FAQ

Common questions about unit conversion, DPI, and best practices for print and digital workflows.

How do I convert millimeters to inches?

Divide millimeters by 25.4. The tool performs this automatically and displays the exact inch values (two decimals).

What DPI should I use for printing?

For professional print, 300 DPI is standard. 150 DPI can be acceptable for large posters viewed at a distance. Use 72 or 96 DPI for screen‑only graphics.

Why do pixel values change when I switch DPI?

Pixels are calculated as inches × DPI. Higher DPI packs more pixels into the same physical size, so pixel dimensions increase accordingly.

Can I lock the aspect ratio?

Yes. Enable ‘Lock aspect ratio’ and changing width or height will automatically update the other dimension to keep proportions.

Are the conversions precise enough for print?

Yes. The tool uses standard formulas with sensible rounding suitable for print production and layout tools.

Can I prefill values from a paper size page?

Yes. Append query parameters like ?w=210&h=297&dpi=300&unit=mm to the URL to pre‑populate the converter.