A digital caliper or spec sheet often gives a decimal inch reading, but tape measures and rulers are marked in fractions — this converts between them.
How it works
The decimal value is rounded to the nearest fraction of the chosen precision (down to 1/64″), then reduced to its simplest form.
What this does not include
This does not include metric-to-fraction conversion — enter a decimal inch value directly; convert from millimeters first if needed.
How to use this calculator
- Enter the decimal inch value and choose the nearest precision.
Frequently asked questions
Why round to a fraction instead of just using the decimal?
Because standard rulers, tape measures, and drill bit sets are marked in fractions of an inch, not decimals — a fraction is more directly usable at the workbench.
What precision should I choose?
1/16″ matches most tape measures; finer work like machining or woodworking joinery often uses 1/32″ or 1/64″.
What happens if the decimal rounds up to a whole number?
The calculator correctly carries that into the whole-number part of the result rather than showing an invalid fraction equal to 1.
