17 quick calculators for the numbers a site engineer reaches for every day — concrete, rebar, slab reinforcement, plaster, electrical sizing, generator/UPS sizing, water tanks, pipe & bar weights, and more. Each tool runs on its own dedicated page with the formula explained, common questions answered, and results you can trust.
Estima · Site Tools — looking for a full project cost breakdown instead? Try the main Estimator.
Cement, sand, and aggregate quantities from wet volume and mix ratio using the standard 1.54× dry-volume factor.
Concrete volume plus single-layer reinforcement mesh for a rectangular RCC slab. Double the steel for top and bottom mats.
Wall or ceiling area × thickness → cement and sand needed with the standard 1.27× dry-volume allowance for plaster mortar.
Net paintable area, number of coats, and coverage rate → litres or gallons required, including a wastage allowance.
Floor or wall area divided by tile size, with a wastage allowance for cuts and breakage, plus box count.
Brick or block count from wall area, face dimensions, and mortar joint thickness. Works for any block size worldwide.
Standard formula weight = diameter² ÷ 162 per metre. Total weight from bar diameter and length, metric or imperial bar sizes.
Mild steel bar unit weight from cross-sectional area using standard density (7850 kg/m³). Square, flat, or round profiles.
Unit weight for plain steel pipe from OD and wall thickness using the API 5L / ASTM standard formula.
Trench or pit volume with a soil-bulking allowance and optional truck-load count for planning haul-off.
Blondel's rule check for riser and tread comfort given floor-to-floor height and a target riser dimension.
Copper conductor voltage drop using IEC 60228 resistivity. Single-phase and three-phase, with AWG or mm² cable sizes.
Base ampacity reference table for copper conductors. A starting point — always apply your code's derating factors.
Single vertical driven rod resistance using the IEEE Std 80 simplified formula, with typical soil resistivity reference data.
Rough kVA sizing for backup generators and indicative battery bank Ah for UPS/inverter setups.
Most online construction calculators multiply a flat rate by your square footage and call it a day. Estima's site tools are built differently — each one runs a real engineering calculation from first principles, the same way a quantity surveyor or site engineer would work it out on paper.
The concrete calculator doesn't guess bags per cubic metre; it applies the standard 1.54× dry-volume factor to account for voids and bulking, splits the result across your mix ratio, and converts cement volume to bag count using bulk density. The rebar weight calculator uses the universally published diameter² ÷ 162 formula verified against steel mill tables. The voltage drop calculator uses IEC 60228 copper resistivity at 20°C, not a rule-of-thumb percentage.
Every tool supports metric and imperial units with live conversion at the input and output boundaries. The math itself always runs in SI units internally, so you get the same result whether you enter millimetres or inches. Nothing is sent to a server — all calculations happen in your browser, which means they work offline and your project data stays private.
These calculators are designed for early budgeting, site estimation, and quick cross-checks. They are accurate enough to order materials or plan a pour, but for structural elements always confirm bar sizes, concrete grades, and cable ratings against your licensed engineer's drawings and your governing building code.
Yes — all 17 site calculators are completely free with no signup required. They run entirely in your browser, so no project data is sent to our servers.
Each calculator uses engineering-grade formulas verified against published standards (ACI, ASCE, IEC, AASHTO) and real quantity-surveying practice. They are accurate for early budgeting and site estimation, but always confirm critical quantities with a licensed engineer or quantity surveyor before final procurement.
Yes. Every calculator supports both metric and imperial units. You can override the default for your selected country at any time. All conversions happen locally in your browser.
Estima currently prices and converts across 10+ regions including Pakistan, India, the United States, the United Kingdom, Canada, Australia, the UAE, Saudi Arabia, Qatar, and the European Union.
No. Every calculator, guide, and article on Estima is fully accessible without signing up. An account is only relevant if you choose to use EstimaOS to manage an active build.