ConstruMath: Construction Calc

ConstruMath is a feet-inch-fraction construction calculator for carpenters, framers, contractors and anyone building something. Type a dimension the way you say it — 5 feet 7 and 1/2 inches — and get answers you can mark on the board.

EVERY ANSWER AT ONCE
Press Stair and see riser height, number of risers, tread width, treads, stringer length and angle together, not one number per tap. Rafters, rake walls and circles work the same way. Tap any answer to use it in your next calculation.

DIMENSIONAL MATH
• Add, subtract, multiply and divide feet, inches, fractions, yards and metric
• Length × length = area, area × length = volume, automatically
• Fractions to 1/2, 1/4, 1/8, 1/16, 1/32 or 1/64
• Convert between ft-in-fractions, decimal feet, inches, yards, meters, centimeters and millimeters, including square and cubic units

FRAMING AND ROOFS
• Right triangles: rise, run, diagonal and pitch in inches per foot, degrees, percent grade or ratio
• Common rafters, regular and irregular hip/valley rafters
• Jack rafters at your on-center spacing, on both sides of an irregular roof
• Rake-wall studs, base height and wall angle
• Square up a foundation with the diagonal

STAIRS
• Floor-to-floor rise, with or without a fixed run
• Riser and tread sizes rounded the way you will cut them, with over/under
• Stringer length and stair angle; a warning when the riser is taller than you want

ESTIMATING
• Concrete in cubic yards, with total cost
• Board feet and lumber cost per thousand
• Weight from volume in tons, pounds, metric tons and kilograms
• Circle area, circumference and arc angle

ON THE JOB
• Memory with total, average and count
• Live paper tape of your calculation
• Stored riser, tread, on-center spacing and weight per volume
• Large high-contrast keys, optional key vibration
• English and Spanish
• Built-in help with worked examples
• Your work stays on screen when you close and reopen the app

Free with a small banner. A one-time "Remove ads" purchase removes it — no subscription. Every calculator function is free either way.