Civil Engineering Calculators
Beam Deflection Calculator
Calculate beam deflection for simply supported or cantilever beams under a point or uniform load, using standard linear-elastic formulas.
Concrete Compressive Strength Calculator
Calculate concrete compressive strength (f'c) from a standard cylinder test's failure load and diameter.
Concrete Mix Calculator
Calculate cement bags, sand, aggregate, and water needed for a concrete pour from a target volume and mix ratio, using the standard dry-volume method.
Culvert Sizing Calculator
Calculate the required culvert diameter from design flow, slope, and Manning's roughness, rounded up to the nearest standard pipe size.
Cut and Fill Earthwork Volume Calculator
Calculate earthwork volume between two surveyed cross-sections using the standard Average End Area method.
Drainage Flow Calculator
Calculate peak stormwater runoff using the Rational Method from surface type, rainfall intensity, and drainage area.
Euler Column Buckling Calculator
Calculate the critical axial load at which a slender column will buckle using Euler's formula.
Factor of Safety Calculator
Calculate factor of safety from a material's ultimate strength and the actual applied stress in a structural design.
Grade Slope Percentage Calculator
Calculate slope grade percentage and equivalent angle in degrees from rise and run measurements.
Manning's Equation Calculator
Calculate open channel flow rate using Manning's Equation from roughness coefficient, cross-sectional area, hydraulic radius, and slope.
Pavement Thickness Calculator
Estimate pavement thickness from design traffic (ESAL) and subgrade strength (CBR), following the general shape of AASHTO-style pavement design.
Pipe Flow Velocity Calculator
Calculate flow velocity inside a pipe from flow rate and pipe diameter using the continuity equation.
Rational Method Runoff Calculator
Calculate peak storm runoff from a small drainage area using the standard Rational Method formula.
Rebar Weight Calculator
Calculate the total weight of reinforcing steel bar (rebar) from bar diameter and total length using standard steel density.
Relative Compaction Calculator
Calculate relative compaction percentage by comparing field-measured soil density against maximum Proctor test density.
Retaining Wall Design Calculator
Calculate the active earth pressure and total lateral thrust on a retaining wall using Rankine's active earth pressure theory.
Slope Stability Calculator
Calculate the factor of safety for a dry or saturated slope using the infinite slope method, from cohesion, friction angle, and slope geometry.
Soil Bearing Capacity Calculator
Calculate allowable bearing capacity for strip, square, or circular footings using Terzaghi's bearing capacity theory and a chosen factor of safety.
Structural Load Calculator
Calculate total structural load and force on a member by summing dead, live, snow, and wind loads over its tributary area.
Traffic Load Calculator
Calculate a structure's design load from vehicle weight, number of lanes, and a dynamic impact factor for moving traffic loads.
Engineering That Has to Hold
Civil engineering math carries real consequences — a beam sized wrong, a slope stability calculation skipped, or a concrete mix under-strength can mean structural failure. These ten calculators cover the load, material, and design math used in infrastructure engineering.
Abrams' Law in Practice
Established over a century ago, Abrams' law describes a consistent relationship in concrete: lower water-cement ratios produce higher compressive strength.
Engineer's note: very low water-cement ratios make concrete much harder to place and work with, often requiring admixtures to maintain workability — the ratio chosen balances required strength against practical placement on site, not strength alone. Check mix designs with the Concrete Mix Calculator.
Popular Civil Engineering Calculators
- Beam Deflection Calculator — calculates how much a beam bends under a given load.
- Soil Bearing Capacity Calculator — determines the maximum load soil can safely support before foundation failure.
- Slope Stability Calculator — assesses whether an embankment or slope is at risk of failure, though results depend heavily on site-specific soil type and moisture, not angle alone.
Related: Construction Calculators for material takeoffs, Mechanical Engineering Calculators for mechanical load analysis.