About mmintoinches.com
Exact millimeter and inch conversions — calculated, checked and free to use.
Who Runs This Site
mmintoinches.com is an independent website run by Johnson, a web developer and online publisher based in South Africa. I build and maintain every page on the site myself.
I started it with one goal: a single place where every common millimeter size has a clear, exact answer in inches — including the tape-measure fractions most converters leave out. Metric and imperial measurements still live side by side in workshops, kitchens, hardware stores and online shops, and a small conversion mistake can mean the wrong drill bit, a part that does not fit or a wasted order.
How the Numbers Are Calculated
Every value on this site comes from one exact definition: 1 inch = 25.4 millimeters. This has been the international standard since the 1959 international yard and pound agreement, so there is no approximation in the conversion itself.
- Decimal inches are calculated as millimeters ÷ 25.4 and rounded to 4 decimal places.
- Millimeters are calculated as inches × 25.4 and rounded to 2 decimal places, using standard half-up rounding (so 3/8″ = 9.525 mm shows as 9.53 mm).
- Fractions are the nearest 1/16 inch on charts (and 1/64 inch in the converter), and are always marked as approximate.
- Exact values such as 2″ = 50.8 mm are highlighted on our charts so they are never confused with rounded ones.
Values are generated by formula rather than typed by hand, and the printable charts are checked row by row before they are published.
What You Will Find Here
- An instant mm to inches converter with decimal, fraction and feet + inches results
- A dedicated page for every whole millimeter from 1 mm to 300 mm
- Free printable charts: MM to Inches and Inches to MM (PDF)
- Reference pages for small sizes, workshop and large sizes and popular conversions
- Related tools: Inches to MM, CM to Inches and MM to Feet
Found a Mistake?
Accuracy is the whole point of this site. If you spot a value that looks wrong, a broken link or anything confusing, please get in touch or email support@mmintoinches.com. Corrections are checked and fixed as quickly as possible.
How This Site Is Funded
mmintoinches.com is free to use. It is supported by advertising and by affiliate links: as an Amazon Associate I earn from qualifying purchases, at no extra cost to you. Product recommendations, such as our guides to digital calipers and tape measures, are chosen for usefulness, and the conversions on this site are never influenced by advertisers. See our Privacy Policy and Terms of Service for details.