How to use the decimal to fraction calculator
- Enter the decimal measurement.
- Choose the smallest increment you want to mark or measure.
- Check the rounding difference before using the fraction for close-fitting joinery.
The formula
Rounded measurement = round(decimal × denominator) ÷ denominator; reduce the fraction to lowest terms.
Worked example
0.708661 in rounds to 45/64 in, or 0.703125 in. The rounded mark is about 0.005536 in smaller than the original.
Before you measure and cut
A tape fraction is useful for marking, but it can lose more precision than a caliper or machine setting.
Fractions are simplified after rounding: 32/64 becomes 1/2. That does not change the requested rounding increment.
Frequently asked questions
Is this an exact rational conversion?
No. It rounds to a selected power-of-two denominator for workshop use.
How are halfway values rounded?
Exactly halfway values round away from zero, so the positive and negative versions use the same magnitude.