Carpenter Square & Stair Calc

The job-site calculator contractors have trusted since 2017. Tape measure in > answer out. Corner squaring, stair layout & bubble level in one app. No signup needed.

Three essential construction tools in one pocket-sized app. Carpenter Square gives you corner squaring (Pythagorean theorem), a complete stair calculator with building code support, and a digital bubble level — all with direct tape measure input in feet, inches, and sixteenths. No decimal conversion. No signup. Just open and go.

CORNER SQUARING CALCULATOR

Square your corners in seconds — not minutes. Enter any 2 sides of a right triangle and we instantly calculate the 3rd.

• Input directly in feet, inches, and sixteenths — straight from your tape measure • Calculates any missing side: Leg A, Leg B, or hypotenuse • Visual triangle diagram with all three measurements labeled • Save and recall your 7 most recent calculations • Input validation catches impossible triangles before you waste material

Whether you're checking a foundation, squaring a deck frame, or verifying a wall layout — get your answer and get back to work.

STAIR CALCULATOR

Enter your floor-to-floor height and get a complete stair layout instantly. No more guessing riser counts or pulling out a separate calculator for stringer cuts.

• Number of risers and treads — calculated to code • Exact riser height — evenly distributed across all steps • Customizable tread depth (default 10", adjustable 9"–14") • Total run — the full horizontal distance of your staircase • Stringer length — the diagonal measurement for your cut • Required floor opening — sized to your headroom clearance • Stair angle in degrees • Residential (8" max rise) and Commercial (7" max rise) building code support • Headroom clearance calculation (default 6'8" minimum) • Visual staircase diagram with labeled dimensions • Save and recall previous staircase designs

Building code compliance note included with every calculation. Always verify with your local building official.

DIGITAL BUBBLE LEVEL

Turn your iPhone into a precision level. Uses your device's built-in motion sensors to give you real-time tilt measurements.

• Animated bubble indicator moves with your device • Angle displayed in degrees with 0.1° precision • +/- 25° measurement range • No calibration needed — works immediately

BUILT FOR THE JOB SITE

Carpenter Square was designed and engineered by contractors with more than 30 years in the building industry. Every feature is built around one principle: tape measure in, answer out.

• Measurements in feet, inches, and sixteenths — the way you actually measure • Fractions auto-simplify for easy reading (8/16 > 1/2, 14/16 > 7/8) • Save up to 7 recent calculations per tool — tap to recall instantly • Visual diagrams for every calculation so you can verify at a glance • Under 2.5 MB — downloads in seconds, even on spotty job-site signal • No account required. No data collected. No ads. Just the tools you need.

Perfect for carpenters, framers, general contractors, remodelers, deck builders, stair builders, and anyone who needs fast, accurate construction math without fumbling with a calculator.

Download Carpenter Square and get back to building.