What is 0.625 in inches?
0.625" is 5/8". To check any decimal against a tape, multiply it by 16: 0.625 × 16 = 10, so it is 10/16", which reduces to 5/8". On the tape it is the mark halfway between 1/2" and 3/4".
Where is 3/8 on a tape measure?
3/8" is 6/16": count six of the smallest marks past the inch line on a tape marked in sixteenths, or three of the eighth-inch marks. It sits halfway between 1/4" and 1/2", at 0.375" or 9.525 mm. The shaded rows in the first table are the sixteenths, the marks most tapes carry.
Decimal to fraction: rounding to the nearest mark
Most decimals fall between marks. To round one to sixteenths, multiply by 16 and round to a whole number: 0.3" × 16 = 4.8, which rounds to 5, so 0.3" is about 5/16". The last table on this page does the same for 0.05" to 0.95" to the nearest 1/8", 1/16" and 1/32". A decimal exactly halfway between two marks rounds up.
Millimeters to inches
Divide millimeters by 25.4. 10 mm is 0.393701", and 0.393701 × 16 = 6.3, so to the nearest sixteenth it is 6/16", which is 3/8". The inch has been exactly 25.4 mm since 1959; NIST’s Handbook 44 gives it as 2.54 centimeters, exactly.
Inches to decimal feet
Divide inches by 12. 7-3/8" is 7.375 ÷ 12 = 0.6146 ft. The second table does this for every eighth of an inch from 0" to 11-7/8", to four places: find the whole inches in the left column and the fraction across the top.
How the decimals are rounded
Construction Calculator 1.1.1’s unit converter works in exact fractions and shows six decimal places, dropping trailing zeros, which is how the first table is written. The second table has four places, as the app’s units line under an answer shows decimal feet.