Practical measurement guide
Tape Measure Fractions Guide
Understand common tape-measure fractions, ruler increments, decimal inches, and metric equivalents.
Tape-measure fractions are common inch increments such as halves, quarters, eighths, and sixteenths.
in
Decimals and fractions work, for example 1.5, 1/2, or 1 1/2.
mm
Try a value
Fractions
0.125 in = 3.175 mm
0.125 in × 25.4 = 3.175 mm
Decimal inches0.125 in
Feet + inches0 ft 0.125 in
Nearest 1/16 inch1/8"
Common tape-measure increments
Many tape measures mark halves, quarters, eighths, and sixteenths of an inch. Finer tools may include thirty-seconds or sixty-fourths.
Convert fractions carefully
First simplify the fraction when possible, then convert it to decimal inches before calculating centimeters or millimeters.
Related measurement tools
Frequently asked questions
What are common tape-measure fractions?
Common marks include 1/2, 1/4, 1/8, and 1/16 inch.
How do I convert a tape fraction to mm?
Convert the fraction to decimal inches, then multiply by 25.4.