Science & Engineering
Electricity, mechanics, thermodynamics, chemistry and waves with SI units. Educational estimates, not certified engineering.
- Ohm's Law CalculatorSolve Ohm’s law and the power equations: enter any two of voltage, current, resistance and power to find the other two.
- Electrical Power CalculatorCalculate real, apparent and reactive power for DC, single-phase AC and three-phase AC circuits from voltage, current and power factor.
- Voltage Drop EstimatorEstimate voltage drop in copper or aluminium cable from length, size (mm² or AWG), current and circuit type.
- Resistor Color Code CalculatorDecode 4-, 5- and 6-band resistor colour codes into resistance, tolerance range and temperature coefficient.
- Series Resistance CalculatorAdd resistors in series and see the current and voltage across each one for a given supply voltage.
- Parallel Resistance CalculatorCalculate the equivalent resistance of resistors in parallel, total conductance and current for a given voltage.
- Electrical Energy Cost CalculatorCalculate the electricity cost of running an appliance from its power, hours of use and your price per kWh.
- Electricity Consumption CalculatorEstimate household electricity use from a list of appliances, wattages, hours per day and quantities.
- Battery Runtime EstimatorEstimate battery runtime from capacity (Ah, mAh or Wh), voltage, load (W, A or mA), usable depth of discharge and inverter efficiency.
- Solar Panel Output EstimatorEstimate daily, monthly and yearly solar PV output from panel ratings, peak sun hours and system losses.
- Heat Energy CalculatorCalculate the heat energy to warm or cool a material with Q = mcΔT, in kJ, kWh, kcal and BTU.
- Kinetic Energy CalculatorCalculate kinetic energy from mass and velocity, or solve for velocity or mass from a known energy.
- Potential Energy CalculatorCalculate gravitational potential energy from mass, height and gravity on Earth, the Moon, Mars or Jupiter.
- Velocity CalculatorCalculate average velocity from distance and time, or final velocity from initial velocity, acceleration and time.
- Acceleration CalculatorCalculate acceleration from a change in velocity over time or from distance covered from rest, with the value in g.
- Force CalculatorApply Newton’s second law F = m a to find force, mass or acceleration, with the weight of the mass on Earth.
- Work CalculatorCalculate mechanical work from force, displacement and the angle between them, plus average power if time is given.
- Momentum CalculatorCalculate momentum p = mv and the result of a perfectly inelastic collision, including the kinetic energy lost.
- Density and Mass CalculatorSolve ρ = m/V for density, mass or volume, with density in g/cm³ and whether the object floats in water.
- Pressure CalculatorCalculate pressure from force and area, or hydrostatic pressure at a depth in a fluid (gauge or absolute).
- Ideal Gas Law CalculatorSolve the ideal gas law PV = nRT for pressure, volume, moles or temperature.
- Molarity CalculatorCalculate molarity from solute mass, molar mass and solution volume, or the mass needed for a target concentration.
- Dilution CalculatorSolve the dilution equation C₁V₁ = C₂V₂ for any missing value, with the solvent volume to add and the dilution factor.
- pH CalculatorCalculate pH and pOH from [H⁺] or [OH⁻], for strong acids and bases, or for a weak acid with a known Ka.
- Wavelength and Frequency CalculatorConvert between wavelength and frequency for light, radio and sound, with period and photon energy.
These are educational estimates. Electrical, structural and other safety-critical work must comply with local codes and be designed or checked by a qualified professional.