Home › Tools › Add fractions › 5/16 + 13/16

5/16" + 13/16"

Adding two fractions of an inch, exactly — the everyday jobsite arithmetic that a decimal calculator gets wrong. Reduced, carried, and shown in millimetres.

5/16" + 13/16" =

=1-1/8"

Sum

1-1/8"

Decimal inch

1.125"

Millimetres

28.575 mm

5/16" − 13/16"

-0-1/2"

The work

Over a common denominator

Put both over 16: 5/16 = 5/16 and 13/16 = 13/16. Add the tops: 5/16 + 13/16 = 18/16, which carries past one inch. Reduced, that's 1-1/8" (1.125 inches). TapeMath tracks it as an exact fraction, so it lands dead on the tape mark.

Keep going

5/16" to decimal 13/16" to decimal All fraction sums Add it on the calculator

The same math, offline

Every calc, on your tape measure — even with no signal.

TapeMath for iPhone runs this exact engine offline, adds rafters, stairs, studs, pitch and a paperless tape, and the key layout your thumbs already know. $9.99 once — no subscription, ever.

See the app

Coming soon — TapeMath is in final App Review. Meanwhile, use the free web calculator →