Construction Calculator

BuildMath is the construction calculator that works the way your tape measure does. Type 12' 6-1/2" exactly as you read it, then add, subtract, multiply and divide in feet, inches and fractions and get answers you can cut to.

A feet and inches calculator, fraction calculator, roofing calculator, stair calculator and concrete calculator in one app. Built for carpenters, framers, roofers, contractors, builders, remodelers and serious DIYers.

FEET INCH FRACTION CALCULATOR
• Dedicated Feet, Inch and fraction keys for fast tape measure math
• Round answers to the precision you choose, from 1/2" down to 1/16", 1/32" or 1/64"
• Every result shown instantly in decimal feet, inches, yards and meters
• Mix in metric anytime: m, cm and mm

ROOF PITCH & RAFTER CALCULATOR
Enter any two of pitch, rise and run, and BuildMath solves the rest:
• Common rafter (diagonal) length
• Hip and valley rafter length
• Roof slope angle and grade
• Jack rafter lengths at your on-center spacing
• Compound miter cuts for crown molding

STAIR CALCULATOR, SHAPES & LAYOUT
• Stair stringer calculator: risers, treads and stringer length from total rise
• Arcs, circles and regular polygons
• Studs, blocks, drywall sheets, footings and board feet
• Built-in memory: M+, MR, MC and 9 storage registers

17 STEP-BY-STEP CONSTRUCTION ESTIMATORS
Fill in the fields, read the results. No formulas to remember.
• Concrete calculator for slabs and footings: cubic yards and bags, waste included
• Drywall, block wall, flooring and tile estimators
• Wall framing and stud calculator
• Common rafter and hip/valley, basic and advanced
• Stairs, basic and advanced (headroom, opening, throat)
• Circles, columns, cones and arcs
• Crown molding miter calculator
• Fraction calculator and a full unit converter for length, area, volume and weight

TRIANGLE CALCULATOR
Enter any three sides or angles and watch the diagram update live. Get area, perimeter, height and every missing side and angle. Switch to right triangle mode when you only know two values, perfect for squaring a layout.

BUILD YOUR OWN CALCULATORS
Create custom calculators with your own inputs and formulas for the jobs you do every day.

EVERY ANSWER ON THE TAPE
• Every calculation is saved to a running tape
• Tap any line to reuse that answer
• Save tapes by job, like "Kitchen Remodel" or "Garage Slab"
• Share a tape as text with your crew or client in one tap

MADE FOR THE JOB SITE
• Big, easy-to-hit keys, even with work gloves on
• 6 pro themes: Hi-Vis, Graphite, Blueprint, Timber, Architect and Sandstone, each with a matching app icon
• Light and dark mode that follows your system
• Tablet layout with the live tape always beside the keypad
• Quick tutorial and a help guide for every key
• No account needed, and all calculations stay on your device

Whether you're framing a wall, cutting rafters, laying out stairs or ordering concrete, BuildMath is the carpentry and construction math calculator that keeps every measurement in feet, inches and fractions.

Measure twice, calculate once. Download BuildMath and get it right the first cut.

PRIVACY & SUPPORT
• Privacy Policy: https://buildmath.retrytech.site/privacy/
• Terms of Use: https://buildmath.retrytech.site/terms/
• Contact us: help@retrytech.com
Questions, feature ideas or a calculator you'd like to see? Write to us anytime.