Engineering calculators
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
Most used engineering calculators
Electrical fundamentals
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.
Mechanical loads and motion
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.
Safety factors and when to stop calculating
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.
Every engineering calculator
Engineering calculator questions
Do these calculators use metric or imperial units?+
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.
Can I use these results for a real installation?+
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.
Do the electrical calculators handle AC as well as DC?+
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.
Is a safety factor already included in the results?+
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.