Free Engineering Calculators

Voltage Divider Calculator

Calculate output voltage from a resistor voltage divider circuit using Vout = Vin × R2/(R1+R2).

Gear Ratio Calculator — RPM, Torque & Trains

Calculate gear ratio, output RPM, torque multiplier, and speed change for simple gear pairs and multi-stage gear trains. Visual SVG diagram included.

Beam Deflection Calculator

Calculate maximum deflection and slope for cantilever, simply supported, and fixed-fixed beams with section presets, material library, and serviceability code checks.

Pipe Flow Calculator — Darcy-Weisbach

Calculate fluid flow rate, velocity, and pressure drop in pipes using the Darcy-Weisbach equation.

Power Factor Calculator — AC Circuit

Calculate power factor, real power, reactive power, and apparent power for AC circuits.

Resistor Series & Parallel Calculator

Calculate equivalent resistance for resistors in series, parallel, or mixed configurations. Add or remove resistors dynamically and see the result instantly.

Concrete & Cement Calculator

Calculate concrete volume for slabs, footings, walls, columns, and circular pads. Shows bags needed (25 kg, 40 kg, 60 lb, 80 lb), cubic yards, and optional cost estimate.

Wire Gauge Calculator — AWG, Current & Resistance

Look up AWG wire gauge specs: current-carrying capacity (ampacity), resistance per foot, voltage drop, and cross-sectional area. Calculate wire size from current load and find safe circuit wire length.

Battery Life Calculator — Runtime & Charge Cycles

Estimate battery runtime from capacity (mAh/Wh) and current draw. Calculate charge cycles to 80% capacity, find the right battery size for your device, and compare battery packs.