# Mechanical Power Calculator

> Find power from work and time or from force and speed, or the work done or time needed at a given power, in watts, kilowatts and horsepower.

Category: Science & engineering · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/mechanical-power-calculator

Power is the rate of doing work: P = W ÷ t. For a steady push it is also force times speed, P = F v. Solve for power, work or time.

Also called: Work–power–time calculator, P = Fv calculator.

## Inputs
- Calculate from (options: Work and time, Force and speed; default work_time)
- Solve for (options: Power, Work, Time; default power)
- Work or energy (default 6000)
- Work unit (options: joules (J), kilojoules (kJ), megajoules (MJ), watt-hours (Wh), kilowatt-hours (kWh), calories (cal), kilocalories (kcal), foot-pounds (ft·lbf), BTU; default j)
- Power (default 300)
- Power unit (options: watts (W), kilowatts (kW), megawatts (MW), mechanical horsepower (hp), metric horsepower (PS), ft·lbf/s, BTU/h; default w)
- Force (default 500)
- Force unit (options: newtons (N), kilonewtons (kN), pounds-force (lbf), kilograms-force (kgf); default n)
- Speed (default 2)
- Speed unit (options: m/s, km/h, mph, ft/s, knots; default ms)
- Time (duration) (default 20)
- Time unit (options: seconds, milliseconds, minutes, hours; default s)

## Results
- Result
- Power
- Power
- Power (mechanical hp)
- Power (metric hp)
- Work over the duration
- Time

## Formula

```
P = W ÷ t;  W = P t;  t = W ÷ P;  P = F v
```

Where:
- P: power in watts (1 hp = 745.700 W; 1 PS = 735.499 W)
- W: work or energy in J
- t: time in s
- F: force along the motion in N
- v: speed in m/s

## Worked example
1. P = W ÷ t.
2. P = 6,000 J ÷ 20 s = 300 W (0.3 kW, about 0.40 hp).

**Result:** Doing 6,000 J of work in 20 seconds takes 300 W of mechanical power.

## What the result means

This is output (useful) power. A motor or engine must draw more input power than this because of its efficiency losses; divide by the efficiency to size the drive. For torque and rpm, use the Horsepower Calculator.

## Assumptions and limits
- Average power over the stated time; force and speed along the same line.
- Peak power during acceleration can be much higher than the average.

## Questions

### How many watts is one horsepower?

Mechanical (imperial) horsepower is 550 ft·lbf/s = 745.700 W. Metric horsepower (PS) is 75 kgf·m/s = 735.499 W.

### Why use P = F v?

For steady motion it avoids needing a time: a cyclist pushing 20 N of drag at 10 m/s needs 200 W.

## Sources
- [BIPM: The International System of Units (SI)](https://www.bipm.org/)

## Related calculators
- [Horsepower Calculator](https://calculators.geekmidst.com/calculators/horsepower-calculator)
- [Work Calculator](https://calculators.geekmidst.com/calculators/mechanical-work-calculator)
- [Kinetic Energy Calculator](https://calculators.geekmidst.com/calculators/kinetic-energy-calculator)
- [Potential Energy Calculator](https://calculators.geekmidst.com/calculators/potential-energy-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/mechanical-power-calculator