CivilCalcInfrastructure & Hydraulics
Pipe Slope CalculatorCheck grade between two elevations using horizontal run and elevation difference.→Stormwater Runoff CalculatorEstimate peak runoff from a drainage area with the rational method.→Sewer Pipe Sizing CalculatorPerform preliminary gravity sewer sizing from design flow, slope and manning roughness.→Manning Flow CalculatorEstimate discharge and mean velocity in open channels or partially full gravity conduits.→Pipe Diameter CalculatorEstimate a theoretical internal diameter from flow rate and target velocity.→Pipe Pressure Drop CalculatorEstimate friction head loss in pressurized pipe using the darcy–weisbach relationship.→Hazen-Williams CalculatorExplore water-pipe flow, diameter and friction loss using the hazen–williams c coefficient.→Pipe Volume & Cross-Section CalculatorCalculate circular internal area and contained volume for a known inside diameter and length.→Pump Power CalculatorEstimate hydraulic and input power from flow, total dynamic head and overall efficiency.→
Structures & Building
Concrete CalculatorCalculate concrete volume and an optional waste allowance for simple prismatic elements.→Rebar Weight CalculatorEstimate reinforcing steel unit weight and total mass from bar diameter, length and quantity.→Formwork CalculatorEstimate concrete-contact formwork area for columns, beams, walls and similar elements.→Masonry CalculatorEstimate net wall area, approximate unit quantity and allowance for blocks or bricks.→Stair CalculatorCheck riser count, riser height, tread depth and common stair proportion rules.→Construction Cost CalculatorEstimate a preliminary building cost from gross area and a selected cost per unit area.→
Earthworks & Site
Cut and Fill CalculatorEstimate earthwork volumes from section geometry and compare cut against fill.→Excavation CalculatorEstimate in-situ excavation, loose volume after swell and approximate truck trips.→Terrain Slope & Elevation CalculatorConvert between elevation difference, horizontal distance, grade and target elevation.→Side Slope CalculatorConvert horizontal-to-vertical slope ratio into angle and slope length.→
Roads & Paving
Asphalt CalculatorEstimate asphalt tonnage from paving area, compacted thickness and mixture density.→Paver CalculatorEstimate paving unit quantity, pallet needs and waste allowance from net area.→Curb CalculatorEstimate curb units from alignment length and optionally concrete bedding quantities.→Road Material CalculatorEstimate volume and tonnage for subbase, road base, gravel or other pavement layers.→
Steel
How CivilCalc calculations are presented
Each tool focuses on one engineering task. The governing relationship is shown, units are made explicit and limitations are described so users can review the assumptions behind the result. Core calculations run in the browser and the tools are free to use. CivilCalc is intended for preliminary sizing and checking; final design must follow applicable standards, authority specifications, manufacturer data and review by the responsible engineer.