Mechanical Calculator
A mechanical calculator runs the core equations of classical mechanics in one place. Pick a mode (force, work, power, torque, weight, mechanical advantage), enter the known quantities, and the calculator returns the result in both SI and imperial units. Handy for homework, quick shop-floor checks, and anyone who does not want to open six different tools to size a lever, a rope, or a motor.
The six core mechanical calculator modes
This mechanical calculator covers the classical Newtonian equations that cover 90 percent of practical problems:
- Force (F = m x a). Newton's second law. A 10 kg object accelerating at 9.81 m/s^2 feels 98.1 N of force, roughly the weight of a full 2.5 gallon bucket of water on Earth.
- Weight (w = m x g). The gravitational force on a mass. Weight is a force (newtons), not a mass. A 10 kg object weighs 98.1 N on Earth, 16.2 N on the Moon, and 371 N on Jupiter.
- Work (W = F x d). The energy transferred by a force moving an object over a distance. A 100 N force applied over 5 m does 500 J of work. In imperial, 500 J equals 368.8 ft-lbf.
- Power (P = W / t). The rate of doing work. 500 J in 10 s is 50 W, or about 0.067 horsepower. A modern electric kettle pulls roughly 1800 W, a marathon-running human produces about 250 W average.
- Torque (tau = F x r). Rotational force. A 100 N push at the end of a 0.5 m wrench produces 50 N.m (about 37 ft-lbf) of torque, enough to seat a typical wheel stud.
- Mechanical advantage (MA = load / effort). How much a simple machine multiplies force. A pulley system lifting a 500 N load with 100 N effort has MA = 5. A car jack is typically MA = 50 or higher.
Worked mechanical calculator examples
| Problem | Formula | Result |
|---|---|---|
| Force on a 10 kg mass at 9.81 m/s^2 | F = 10 x 9.81 | 98.1 N (22.05 lbf) |
| Work to lift 20 kg by 2 m | W = (20 x 9.81) x 2 | 392.4 J (289.4 ft-lbf) |
| Power to climb 3 m of stairs in 4 s (80 kg person) | P = (80 x 9.81 x 3) / 4 | 588.6 W (0.789 hp) |
| Torque from 50 N at 0.3 m | tau = 50 x 0.3 | 15 N.m (11.06 ft-lbf) |
| MA of a 4:1 pulley | MA = 400 / 100 | 4:1 |
Mechanical calculator for homework and shop work
If you are learning mechanics for the first time, this mechanical calculator is a good way to double-check hand calculations. Do the algebra yourself, then plug the numbers in here and make sure the answer matches. If you are a machinist or mechanic, the torque and power modes are fastest: enter force and lever arm to size a bolt, or enter work and time to know whether a motor is strong enough.
For ratings and motor sizing, remember the SI-to-imperial conversions this calculator applies: 1 N = 0.2248 lbf, 1 N.m = 0.7376 ft-lbf, 1 W = 1/745.7 hp, 1 J = 0.7376 ft-lbf. The calculator returns both systems so you never have to do the conversion by hand.