Feet-inch ↔ decimal converter

What this calculator does

Three conversions detailers do all day, with the rounding handled: decimal feet to feet-inches-sixteenths, feet-inches-sixteenths back to decimal feet, and decimal inches to the nearest 1/16" fraction. Sixteenths round to the nearest, a sixteenth of 16/16 carries to the next inch and 12" carries to the next foot.

Worked example

A survey elevation of 12.3542 ft is 12'-4 1/4". A dimension that computes to 4.6875" is 4 11/16". Going the other way, 6'-8 3/16" is 6.6823 ft.

Common questions

Why sixteenths and not eighths?

Shop drawings and tape measures are in sixteenths; a sixteenth is the smallest dimension a fabricator lays out. Anything finer than that is a decimal the shop cannot use.

How does it round 1/32" cases?

To the nearest sixteenth; an exact half rounds up. If you need the unrounded value, the decimal result is shown alongside so you can see what was rounded.

Can I use it for negative elevations or below-datum work?

Yes — enter the number with its sign. The feet-inch result keeps the sign.