Feet, inches and fractions, the way you read a tape. Rafter lengths and cuts, full stair layouts with a code check, squaring and board feet, every answer with the working shown. It works with no signal, and you buy it once.
A feet-inch-fraction sum, a 6/12 rafter, a 105-inch stair layout and the jobsite tape. Tap for sound.
The big construction calculators now charge $40 a year, every year, for math that hasn't changed. Rafter does the same jobsite math, shows its work on every answer, and costs less than one year of theirs. Once.
Dedicated ft, in and fraction keys, so 12' 6-3/4" goes in exactly as you'd say it. Add, subtract, multiply and divide, and the working line stays on screen so you can check the chain.
Length times length is area, area times depth is volume, straight to cubic yards. Tap the answer to flip it to decimal feet, inches, yards, meters, centimeters or millimeters.
Common rafter length, total rise, plumb and level cut angles, hip and valley length, and the jack table at 12, 16, 19.2 or 24 inches on center. Set the ridge thickness and overhang and everything recomputes as you type.
Pitch converts live between rise-per-12, degrees and percent. Every result carries the per-foot-of-run number from the framing square, so you can check Rafter yourself.
Measure finished floor to finished floor and Rafter lays out the stair: riser count and height, treads, total run, stringer length, and the stock board to buy.
Riser and tread are checked against IRC defaults with clear pass and fail badges. Your local code is different? Edit the limits in Settings. Step the riser count up or down and watch it all recompute.
Diagonal squaring tells you exactly how far out of square a layout is, and board feet works the way lumber is actually sold, with the cost.
Every result is saved automatically, from the calculator and every solver. Tap any entry to pull the number back into the calculator.
Star the live numbers and label them by job: garage rafters, deck stairs, the trim order. Then text the list, or send it as a CSV to the GC.
Rafter runs entirely on your phone. Answers are instant, with no Calculate button and no spinner, in a basement, on a roof or out past the last cell tower. It doesn't collect your data and there's nothing to log into.
One price. Every future update included. No in-app purchases, no ads, no pro tier.
The construction calculator you own. $19.99, once.