Free construction calculators
Published · Updated · By Sai Nath
MeisterCalc has 12 free construction calculators that run in the browser: an all-in-one calculator for feet, inches, fractions and millimetres, plus concrete, block, stair, decking, roof pitch, slope, feet-and-inches and square-up diagonal calculators, and for India a brick calculator, an M20 concrete mix calculator and a cft, brass and m³ converter.
Each calculator below is free to use on this site, with nothing to install. Each sits on a page that also works the sum by hand, so you can check the answer against the formula. Pick the job, open its calculator and type your own sizes.
Everyday
- Construction calculator, all in oneAdd, subtract, multiply and divide feet, inches and fractions or millimetres, with tabs for area, concrete, roof pitch, stairs, right triangles and conversions.
- Feet and inches calculatorAdd or subtract feet, inches and fractions, and convert feet and inches to mm, cm or m and back, to the nearest 1/16 inch.
- Diagonal calculatorThe diagonal a square frame should measure, and from two measured diagonals, how far out it is and which corners to push.
Concrete and masonry
- Concrete calculatorSlabs, footings and post holes in m³ or cubic yards, with 10% extra, bags from makers’ data sheets, a cost from your own price and slab rebar.
- Block and brick calculatorConcrete blocks (CMU) and bricks for a wall, less doors and windows, plus 5%, with bags of mortar.
Roof and slope
- Roof pitch calculatorPitch as X in 12, degrees and per cent from any one value or from rise and run, plus the rafter line length with the overhang.
- Fall calculatorConvert between %, degrees, 1 in X and rise over run, and get the rise or fall over any length.
Stairs and decks
- Stair calculatorRisers, riser height, treads, going, total run, stringer length, angle, 2R + G and the stairwell opening, in mm or feet and inches.
Decking calculatorBoards across, lineal metres and the order with 10% extra, from the deck size, board width and gap, in mm or feet and inches.
India
- Brick calculator, IndiaBricks for a 9-inch or 4½-inch wall, less doors and windows, plus 5%, with cement bags and sand in cft for the mortar.
- Concrete mix calculator, M20Cement in 50 kg bags, and sand and aggregate in m³, cft and brass, for M20, M15 and M10 nominal mixes.
- CFT, brass and m³ converterConvert cubic feet, brass and cubic metres: 1 brass is 100 cft, or 2.832 m³.
What the app adds
The MeisterCalc app for Android has 16 calculators, each with a live diagram, and every calculation works offline. Concrete, Stairs and Check Square are free. The other 13 (Baluster Spacing, Pitch, Decking, Equal Spacings, Running Measurements, Raked Walls, Triangles, Dumpy Level, Gravel, Soil, Asphalt, Stud Counter and Feet & Inches) unlock with a one-time purchase, no subscription required, or with a weekly subscription that starts with a 3-day free trial. All 16 calculators in the app. It runs on Android 7.0 or later.