Physics & Electrical calculators

What these calculators help with

These tools cover core relationships between voltage, current, resistance, power, distance, time, mass, volume and density. They are useful for classroom checks, early project estimates and quick comparisons. Electrical results are simplified calculations and must not replace cable selection, protection design, testing or inspection by a qualified person.

Choose known and unknown values

Start by identifying the quantity to solve and the values you already know. Ohm’s law links voltage, current and resistance; electrical power adds circuit type and power factor; voltage drop also needs conductor material, size and run length. Motion and density tools follow the same principle: enter compatible known values and solve for the missing one.

Check units and real-world limits

Convert prefixes carefully: milliamps, amps, watts and kilowatts differ by powers of one thousand. Cable length may be one-way while the electrical path is a complete circuit. Material properties and power factor are assumptions, so use values suitable for the actual equipment and operating conditions.

• Do not mix metres with millimetres.
• Confirm AC phase and power-factor assumptions.
• Treat calculated electrical values as planning checks only.