Engineering calculators here handle the routine sizing and checking work that sits behind a design: current and voltage relationships, cable losses over distance, fastener torque, and the load a simple beam carries. They are aimed at electricians, technicians, makers and students who need a defensible number quickly.
6 calculators in this category
Ohm's law ties voltage, current and resistance together: V = I × R. Rearranged, it gives current from a known supply and load, or the resistance needed to limit current to a safe value — the calculation behind every series resistor in front of an LED. Power follows directly as P = V × I, and the heat that power represents is what sets component and conductor ratings.
Over a long cable run, conductor resistance causes voltage drop, so equipment at the far end sees less than the supply voltage. Installation standards typically cap that drop at a few percent, which is why long runs need a larger conductor even when the current itself is modest.
Torque is force applied at a distance from a pivot: τ = F × r. It is why a longer wrench loosens a stubborn bolt with the same hand force, and why fastener specifications are given in newton-metres rather than in force alone. Applying specified torque is a proxy for achieving a target clamping preload in the joint, which is why lubrication changes the required figure.
For motion, acceleration is the rate of change of velocity, a = (v − u) / t, and it links directly to force through Newton's second law, F = m × a. Those two relationships cover most first-pass sizing of actuators, brakes and drive systems.
A calculated result is a nominal value under assumed ideal conditions. Real designs apply a safety factor to cover material variation, temperature, fatigue and installation error, and regulated work — building structure, fixed wiring, lifting equipment — must follow the applicable code rather than a bare formula. Use these tools to size and sanity-check, and have anything load-bearing or life-safety related signed off by a qualified engineer.
Each calculator states the units it expects on the input labels, and several accept a choice of unit. Mixing systems mid-calculation is the most frequent source of wrong answers, so confirm the unit on every field before reading the result.
Use them for sizing, estimating and checking. Any permanent electrical installation, structural member or lifting application must be verified against the relevant national code and, where required, certified by a qualified professional.
The basic Ohm's law and power relationships assume purely resistive loads. With AC and a reactive load you also need power factor and impedance, so treat a DC-style result as an upper-bound approximation for motors, transformers and switching supplies.
No. The calculators return the nominal engineering value. Applying an appropriate safety factor for the material, duty cycle and standard you are working to is a separate step, and the right multiplier depends on the application.