Construction Calculator

It does math in feet, inches and fractions the way a tape measure reads, so 10' 6-1/2" plus 4' 3-3/4" comes out as 14' 10-1/4" instead of a decimal. It also solves roof pitch, rafters, stairs, areas and circles.

Type both lengths with ' for feet and " for inches, for example 5' 3 1/2" + 2' 7 3/4", or use the ft and in keys. The answer comes out in feet, inches and sixteenths: 7' 11-1/4".

Type it with a slash and no spaces, 3/4, or tap a fraction key. For 5 3/4 inches type 5 3/4" or 5-3/4". For sixteenths, type the top number and tap x/16: 5 then x/16 gives 5/16.

Divide by 12. Type the inches with the in key, for example 95.25", and the calculator shows 7' 11-1/4" with 7.938 ft, 2.646 yd and 2.419 m under the result.

Pitch is the rise per 12 inches of run: divide the rise by the run and multiply by 12. A 4 ft rise over a 6 ft run is an 8/12 pitch. In the Rafters tab, choose Rise + Run to get the pitch and the roof angle.

Multiply the run by the slope factor of your pitch and add the overhang the same way, less half the ridge board. With an 8/12 pitch, a 12 ft run, an 18 in overhang and a 1 1/2 in ridge board, a common rafter is 16' 1-13/16" long.

14 risers. A 108 in rise divided by the IRC maximum riser of 7 3/4 in is 13.9, so round up to 14 risers of 7-11/16 in each, with 13 treads.

Multiply length by width in feet. A 12 × 10 ft room is 120 sq ft. Split odd shapes into rectangles and add them up. The Area & Volume tab also gives cubic yards for a given depth.

Yes. The calculator and every tab, from rafters to board feet, switch to Metric, and they open in metric if your country uses it. Type lengths in m, cm or mm, with a decimal point or a decimal comma, and mix them with feet and inches if you like: 2m 35cm comes out as 7' 8-1/2".

Yes. The keypad has large keys, fractions take one tap, and your last calculations stay in History on that device.