Free for everyone
Construction calculators
Free, fast and made for the job site: type feet and inches the way you say them (11' 6", 11 6 or 11.5) and get answers in feet, inches and sixteenths. Or ask Dex in plain words.
- Stair calculatorRisers, treads, total run and stringer length from the total rise.
- Square corner (3-4-5) calculatorThe diagonal that makes a corner 90°, and how far out a corner is.
- Concrete calculatorCubic yards and bags for slabs, footings and round columns.
- Paver and patio calculatorPavers, gravel base and bedding sand for a patio or walk.
- Roof pitch calculatorPitch, angle, rafter length and roofing squares.
- Block wall calculatorCMU block count, courses and mortar for a block wall.
- Gravel, mulch and topsoil calculatorCubic yards, tons and bags for any area and depth.
- Slope and grade calculatorDrop over a run, inches per foot, percent grade and degrees.
Ask Dex anything you’d calculate on site
Plain words, feet and inches. Dex shows the numbers and how it got them.
Dex does this and runs your whole business inside Northdesk → See Northdesk
Made for the way you measure
Every calculator here takes lengths the way they come off a tape: 11' 6", 11 6, 11 ft 6 in, 11.5 or 138", with fractions like 6-1/2". Results come back in feet, inches and sixteenths, with the decimal next to them for the estimate.
Where a code limit matters (stair risers and treads, for instance) the calculator checks it against the IRC and tells you plainly, with a reminder that your local code has the final word.
Questions people ask
Are these calculators free?
Yes. No sign-up, no limits on the calculators. Dex answers a reasonable number of questions per visitor.
Can I type feet and inches?
Yes: 11' 6", 11'6-1/2", 11 6, 11 ft 6 in, 11.5 ft and 138" all work. Metric works too (3.5 m, 350 cm).
How accurate are the results?
The math is exact; lengths are shown to the nearest 1/16" with the decimal next to them. Material weights and bag yields are typical numbers; your supplier’s numbers win.
Who is Dex?
Dex is the AI assistant built into Northdesk, construction business software. Here it answers job-site math questions. Inside Northdesk it also knows your projects, crew and schedule and does the busywork.
For contractors who want more than math
Northdesk runs the whole business: projects, crew, schedule, leads, estimates and money, with Dex built in.
- AI assistant for contractorsDex is the assistant built into Northdesk.
- AI estimating and takeoffDex reads your plans for quantities with the AI takeoff add-on, then drafts the estimate from your own prices, sections and wording.
- Project managementOne page per project with today’s work up front, and the whole business around it: crew, schedule, subs, materials and money, in one place, with Dex built in.
- Concrete contractorsPours that move with the weather, footings measured off the plans, finishers on the right site at 6 AM, and an inspector who signs in before you pour.
Run the day from one desk.
We’ll set Northdesk up around your company: your name, your logo, only what you use. Dex will book you a walkthrough with our team.