RAFTER Construction Calculator

Pay once, own it forever. Feet-inch-fraction math, rafters, stairs, squaring and board feet — instant, offline, with the working shown on every answer.

The construction calculator apps tradespeople relied on for years now charge rent — $40 every year, forever, for the same math. Rafter is the alternative: pay once, own it forever.

Rafter does jobsite math the way you think it: feet, inches, and fractions — on a real keypad, with the working shown on every answer.

PAY ONCE. NO SUBSCRIPTION. NO ACCOUNT. NO ADS. WORKS OFFLINE.

FEET-INCH-FRACTION CALCULATOR

• Add, subtract, multiply, divide in feet-inches-fractions (1/8", 1/16", 1/32")
• Full dimensional math: length × length = area, area × depth = volume — straight to cubic yards
• Tap the display to convert: decimal feet, inches, yards, meters, centimeters, millimeters
• The honest ≈ mark: when a result can't land exactly on a fraction, Rafter tells you

RAFTERS — Common, hip/valley, and jack lengths from pitch and span. Plumb and level cut angles. Jack table at 12/16/19.2/24" OC. Pitch ↔ degrees ↔ percent, live. The framing-square per-foot number on every result so you can verify it yourself.

STAIRS — Total rise in, full layout out: risers, treads, total run, stringer length, and the stock board to buy. Code check against IRC defaults (editable) with clear pass/fail badges. Adjust riser count and watch everything recompute.

SQUARE & LUMBER — Diagonal squaring with out-of-square deviation. Board feet with cost, the way lumber is actually sold.

PAPERLESS TAPE — Every answer lands on the tape automatically. Recall any number with a tap. Star and label figures by job. Text or CSV the whole list to the contractor.

BUILT FOR THE JOBSITE

• Huge keys, extreme contrast, readable in direct sun
• Instant answers — no Calculate button, no spinner, no signal needed
• Siri & Shortcuts: ask for a rafter length or stair layout hands-free
• Your numbers never leave your phone. No data collection. Nothing to log into.

One price. Every future update included. That's the whole deal.