Free Online Tools

Calculate cement, sand, aggregate, and water quantities for concrete mixes. Design by volume, cement bags, or grade presets (M10–M25). Enter mix ratio 1:S:A and water–cement ratio. Metric (m³, kg) and imperial (yd³, lb) units. Free, browser-based.

Calculate steel weight for round bar, rebar, square bar, flat bar, plate, and pipe. Enter dimensions and quantity — get total kg or lb, weight per meter, and volume. Carbon steel density 7850 kg/m³. Metric and imperial units. Free, browser-based.

Calculate pipe flow rate, velocity, friction head loss, and pressure drop. Modes: Q = Av, velocity from flow, Darcy–Weisbach, and Hazen–Williams for water pipes. Reynolds number and flow regime. PVC, steel, and cast iron C presets. Metric and imperial units. Free, browser-based.

Calculate fluid velocity from volumetric flow rate and cross-section geometry. Modes: circular pipe, rectangular channel, annulus, known area, continuity (pipe reducer), and velocity unit converter. Reynolds number and flow regime. Metric and imperial units. Free, browser-based.

Calculate pump hydraulic power, shaft power, and motor sizing from flow rate and head. Modes: hydraulic power (ρgQH), brake power with pump efficiency, motor input with motor efficiency, and power from pressure rise. Results in kW, hp, and W. Water and custom specific gravity. Metric and imperial units. Free, browser-based.

Calculate maximum beam deflection and bending moment for simply supported, cantilever, and fixed-end beams under center point loads or uniform distributed loads. Enter span, E, I, and load — results in mm or inches with L/360 and L/250 limit checks. Free, browser-based.

Calculate axial, shear, bending, and torsional stress from force, area, moment, and geometry. Compare to yield strength for safety factor. Metric (MPa) and imperial (psi) units. Free, browser-based.

Calculate engineering axial strain, shear strain, Hooke's law strain (σ/E), thermal strain (αΔT), and lateral Poisson strain. Results in dimensionless ε, microstrain (με), and percent. Metric and imperial units. Free, browser-based.

Calculate Young's modulus E = σ/ε from stress and strain, or from a tensile test (force, area, elongation). Convert between GPa, MPa, Msi, ksi, and psi. Compare to common material references. Free, browser-based.

Calculate heat transfer by conduction (Fourier), convection (Newton), radiation (Stefan–Boltzmann), overall U-value, and composite wall assemblies. Enter geometry, temperatures, and material properties — get heat rate in W, kW, and BTU/hr with thermal resistance. Metric and imperial units. Free, browser-based.

Calculate linear, area, and volume thermal expansion from temperature change. ΔL = αL₀ΔT, ΔA = 2αA₀ΔT, ΔV = 3αV₀ΔT. Bimaterial gap mode for differential expansion between two materials. Material presets for steel, aluminum, concrete, and copper. Metric and imperial units. Free, browser-based.

Calculate gear ratio, output RPM, and torque multiplier for spur gear trains. Single-stage, compound 2-stage, RPM solver, and tooth-count finder for target ratios. Enter driver and driven tooth counts — get speed reduction and ideal torque gain. Free, browser-based.