Stairs · rafters · jobsite math
Construction math for builders.
Live stair diagrams, rafter cut lists, feet-inch-fraction math, and shop-ready PDFs in one app for iPhone, iPad, and Android. Works offline.
Free to try. $19.99 once for Full Access. No subscription.
Complete stair layouts in seconds.
Enter total rise. CutOnce draws a live, zoomable stair diagram and returns a code-compliant layout: unit rise, unit run, stringer length, and every dimension the crew needs to cut.
- Number of risers and treads
- Individual rise and run dimensions
- Stringer length and layout
- Baluster count and spacing for railings
You shouldn't have to rent your calculator.
Subscriptions suck. Other construction calculators bill you every month just to keep using tools you already use every day. That's BS. CutOnce is one and done: download free, try every calculator for 7 days, and the feet-inch-fraction calculator stays free forever. One payment unlocks everything. No monthly bill. No license checks. Just open it and get to work.
- Free to download and try
- 7-day free trial of every advanced calculator
- One-time purchase for Full Access
- Works offline. No signal needed.
Every rafter cut. Every angle. No trig.
Pitch and span in. Common rafter length, ridge height, birdsmouth, and tail cuts out, all displayed in feet-inch-fractions the way your tape reads.
- Common rafter length from span or run
- Ridge height, HAP, and overhang
- Birdsmouth and tail cut dimensions
- Slope calculations in feet-inch-fractions
Hips, valleys, and jacks on the same sheet.
Backing angles, cheek cuts, king-common spacing, and jack rafter layout, printed right below the common rafter schedule.
- Hip and valley lengths with backing angles
- Cheek cuts for every connection
- King common and jack rafter spacing
Print the plan. Cut to the line.
Every stair and rafter calculation exports to a shop-ready PDF. Open it from the truck, walk it to the saw, cut. No signal, no cell service, no account required.
- Shop-ready stair plans with every cut dimension
- Rafter plans with lengths, angles, and layout marks
- Print from the truck or share straight to the crew
- Works entirely offline. Nothing uploads anywhere.
Enter it the way the tape reads.
Add, subtract, multiply, and divide in fractions the way carpenters actually measure. Free forever on every device. Precision from 1/2" down to 1/64".
- Natural entry: 3' 5-3/16" + 2' 10-1/2"
- All four operations, all in fractions
- Precision: 1/2" through 1/64"
- Free forever, no trial required
Every other calc a builder runs.
One app replaces the scrap-paper math, the formula Googling, and the "I think that's right" guessing. All included with Full Access.
Right Angle
Solve any right triangle from two known sides. Square walls, check layouts, cut braces.
Concrete Bags
Slab or post-hole volume converted to 40 / 50 / 60 / 80 lb bag counts, waste factor included.
Drywall
Sheet counts from 4×8 through 4×14, openings deducted, waste built in.
Deck
Board count, fasteners, posts, and code-compliant balusters for the whole deck.
Roofing Materials
Shingle bundles and squares, sheathing sheets, underlayment, drip edge, and ridge cap — waste factored in.
Blocks & Bricks
CMU and brick counts, mortar yield, and course layout, with optional grout, rebar, and wall weight.
Crown Moulding
Compound miter and bevel angles for crown, flat or nested in position on the saw.
Concrete Footings
Pad and strip footing volume converted to bag counts or ready-mix yards, rebar spec included.
Total Cost
Price out any takeoff. Set your currency, add cost per unit, and every estimate carries a running total.
Paint
Room dimensions to gallons, with coats, coverage, doors, and windows deducted.
Area & Volume
Rectangles, triangles, circles, and irregular shapes — square footage and cubic yards.
Unit Conversion
Imperial ↔ metric. Feet-inch-fractions ↔ decimal. Board feet ↔ linear feet.
Built for iPad. Made for a gloved thumb.
CutOnce is a native iPad app — landscape by default, inputs and results side by side, every inch of the screen put to work. On iPhone, the same precision, scaled for one-hand entry on the job.
Stop calculating. Start building.
Free to download. Buy it once and it's yours. No subscription, ever.