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Civil Engineering Calculators — Engineering

20 free civil engineering calculators in engineering. Each tool shows step-by-step formulas, worked examples, and detailed explanations to help you get accurate results instantly.

All Civil Engineering Calculators

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Asphalt Tonnage Calculator

Calculate tons of asphalt needed from area, thickness, and mix density.

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Catch Basin Size Calculator

Size storm water catch basins from drainage area, runoff coefficient, and rainfall intensity.

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Cbr Value Calculator

Calculate California Bearing Ratio for subgrade strength assessment in road design.

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Culvert Size Calculator

Calculate culvert pipe diameter from peak flow rate and allowable headwater depth.

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Curve Radius Calculator

Calculate horizontal curve radius, length, and deflection angle for road design.

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Darcy Weisbach Calculator

Calculate friction head loss in pipes using the Darcy-Weisbach equation.

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Earthwork Volume Calculator

Calculate cut and fill volumes for earthwork projects using the average end area method.

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Gabion Wall Calculator

Calculate gabion basket quantity and rock fill volume for gabion retaining walls.

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Geogrid Calculator

Calculate geogrid reinforcement layers and spacing for reinforced soil walls and slopes.

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Hazen Williams Calculator

Calculate pipe flow velocity and head loss using the Hazen-Williams equation.

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Mannings Equation Calculator

Calculate open channel flow velocity and discharge using Manning roughness equation.

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Parking Lot Size Calculator

Calculate parking lot dimensions and stall count from total vehicles and layout type.

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Prestressed Concrete Calculator

Calculate prestress losses and tendon force for prestressed concrete beam design.

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Retaining Wall Stability Calculator

Check overturning, sliding, and bearing capacity stability for gravity retaining walls.

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Road Grade Calculator

Calculate road grade percentage and slope from elevation change and horizontal distance.

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Soil Compaction Calculator

Calculate soil compaction percentage from wet density, dry density, and optimum moisture.

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Storm Drain Size Calculator

Size storm drains using the Rational Method from rainfall intensity and drainage area.

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Traffic Flow Calculator

Calculate traffic flow rate, density, and speed using the fundamental traffic flow equation.

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Traffic Signal Timing Calculator

Calculate green, yellow, and all-red phase timing for traffic signal intersections.

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Weir Flow Calculator

Calculate flow rate over rectangular, V-notch, and Cipolletti weirs from head measurement.

About Civil Engineering Calculators

Our civil engineering calculators in engineering are designed for students, professionals, and anyone who needs quick, accurate results. Every calculator includes the underlying formula, step-by-step solutions, and real-world worked examples so you can understand the math behind the answer.

Whether you need to solve a one-time problem or verify your own calculations, these free tools cover the most common civil engineering scenarios. All results are computed in your browser — no data is sent to any server.

What You Can Calculate

This section includes 20 tools: Asphalt Tonnage Calculator, Catch Basin Size Calculator, Cbr Value Calculator, Culvert Size Calculator, Curve Radius Calculator, Darcy Weisbach Calculator, Earthwork Volume Calculator, Gabion Wall Calculator, and 12 more. Each calculator is free to use with no signup required.