Construction Calculator

Concrete, brick, tile, paint, drywall & rebar estimator with formulas shown.

Construction Calculator estimates materials for concrete, mix design, rebar, formwork, structural steel, brick, tile, paint, drywall, flooring and roofing — and shows the formula behind every result, so you can trust the number before you order a single bag. Every calculation works offline, with no ads and no login.

ESTIMATE ANY MATERIAL

✓ Concrete — slabs, footings, round and square columns → m³, yd³ and premix bags in all 5 sizes at once (40/60/80 lb and 25/40 kg)
✓ Mix design — nominal mixes 1:1:2 to 1:4:8 with the 1.54 dry-volume factor → cement bags, sand m³, aggregate m³ and mixing water in litres
✓ Brick & block — 5 standard sizes including concrete blocks, single or double wythe walls, openings subtracted, adjustable mortar joint → brick count, mortar volume and dry-mix weight
✓ Tile — tile count by size and grout gap, grout in kg by the standard formula, adhesive, spare tiles
✓ Paint — perimeter × height minus doors and windows, number of coats, adjustable coverage → liters and gallons
✓ Drywall — sheets, screws and joint compound for 4×8, 4×10 and 4×12 panels
✓ Flooring — boxes needed from area and coverage per box
✓ Roofing — pitch factor from flat to 12/12 → real roof area, squares and shingle bundles
✓ Rebar — two-way mesh with LAP SPLICES: bar count, splice count, ordered length, stock bars and weight for Ø6–Ø25 mm and US #3–#8 bars
✓ Slope & grade — convert between rise/run, percent, ratio 1:n and degrees, plus the true slope length you actually have to order
✓ Plaster & screed — walls (one or both faces, openings deducted), ceilings and floor screeds; thickness and cement:sand mix → mortar, cement and sand
✓ Plot & land area — rectangle, triangle from 3 sides, trapezoid, or any 4-sided plot from its sides plus one diagonal → m², hectares, acres and perimeter

BUILT FOR TRUST

• "Show formula" on every calculator — see exactly how your number was computed, with all source values
• Adjustable waste % — you decide the safety margin, not the app
• Mix metric and imperial in the same calculation — every length field has its own m/cm/mm/ft/in selector
• Cost mode — add unit prices and get money totals instantly
• Numbers formatted for your locale
• Metric or imperial as your default units, set once in Settings
• Your own currency symbol (₫, $, €…) in exported price columns

HOW IT WORKS

1. Pick a calculator and type your dimensions in any unit.
2. Set waste % and, if you like, unit prices.
3. Check the formula, then save the line to a project.
4. Export as PDF or CSV (Pro), with or without calculation details.

WHY CHOOSE US

• No ads — ever. Estimate in peace on the job site.
• No subscription — Pro is a single lifetime purchase.
• No login, no ads — your estimates stay on the phone, and the calculators work in the basement and off the grid.
• Every material calculator listed above is included.

PRO — PAY ONCE

★ Project estimates — add results from any calculator into one project with a grand total
★ PDF and CSV export with project and client name — send a clean quote in minutes
★ Price book — save material prices once, reuse them everywhere
★ Formwork & shuttering — contact area for slabs, beams, columns, walls and footings → plywood sheets with reuse count and release oil
★ Structural steel weight — round, square, flat, pipe, RHS/SHS, angle and plate → kg/m, total kg and tonnes
★ Fence & deck layout, cast-in-place concrete steps with code warnings and concrete + formwork quantities, cut & fill earthwork with swell and shrinkage factors
★ Unlimited saved projects (free: 3)

PRIVACY

Anonymous usage data (screens, features, error codes) helps improve the app — never your numbers, project names or results. Turn it off in Settings.

Results are estimates; check structural work against your local code. Plot areas are guidance, not a land survey.

Construction Calculator is made for builders, contractors, masons, painters, DIY renovators and estimators who want fast, transparent material takeoffs.