Inch Fractions to Decimal, Millimeters & Centimeters
Convert an inch measurement between a nearest-1/16 fraction, a decimal, and millimeters — type a decimal or pick a fraction and read all three at once.
How it works
A tape measure speaks in fractions — sixteenths, eighths, quarters — while calipers, drawings, and spreadsheets speak in decimals, and metric parts speak in millimeters. This tool moves an inch measurement between all three. Type a decimal like 7.4375 and it snaps to the nearest sixteenth, 7 7/16, and to 188.91 millimeters. Pick a fraction from the menus and it reads back the decimal and the millimeter value instead.
Converting a fraction to a decimal is just division: the top number over the bottom, added to the whole inches. So 7/16 is 7 ÷ 16 = 0.4375, and 7 7/16 is 7.4375. Going the other way, the calculator multiplies the decimal by 16, rounds to the closest whole number of sixteenths, and reduces the fraction to lowest terms — 0.4375 × 16 = 7, which stays 7/16. Millimeters come from the exact definition 1 inch = 25.4 mm, so no measurement precision is lost in the trip.
= nearest 1/16 -> 7 7/16 in
= 7.4375 x 25.4 = 188.91 mm