Fractional Inches to Millimetres Converter
Convert fractional inches (like 1 1/2") to mm — and mm to the nearest fraction.
Length, weight, area, volume, speed, data and more — convert any unit offline, free, on Android.
About the Fractional Inches to Millimetres Converter
The AlarmDaddy Fractional Inches Converter handles the fraction-based inch measurements used in woodworking, engineering and DIY. Enter whole inches plus a fraction (like 1 and 1/2) to get millimetres and centimetres, or enter millimetres to get the nearest fractional inch to 1/16.
It is the tool for reading a tape measure or a drawing that uses fractional inches, and for switching a metric measurement into inch fractions.
How to use this converter
- 1Choose inches to mm, or mm to inches.
- 2For inches: enter whole inches and the fraction (numerator and denominator).
- 3For mm: enter the millimetres.
- 4Read the converted value.
The formula
Inches convert to millimetres by multiplying by 25.4. A fractional inch is the whole number plus the fraction; going the other way, millimetres are divided by 25.4 and rounded to the nearest sixteenth of an inch.