Power Calculator
Calculate mechanical power from work/energy and elapsed time, with results in watts.
How It's Calculated
Formula
P = \dfrac{W}{t}Power is the rate at which work is done or energy is transferred: work (or energy, in joules) divided by the elapsed time (in seconds), giving power in watts. This is mechanical power from work and time only. It is not the Horsepower Calculator (which derives power from torque and RPM), the Engine Horsepower Calculator (which estimates power from vehicle weight and quarter-mile trap speed/time), or an electrical power calculation (voltage x current) — those use different inputs and formulas.
Worked Examples
1000 J of work in 10 seconds
- Power = 1000 J / 10 s = 100 W.
0 J of work in 10 seconds
- Power = 0 J / 10 s = 0 W. Zero work over a positive time is a valid, zero result.
Frequently Asked Questions
Is this the same as the Horsepower Calculator?
No. This calculator computes power from work and elapsed time (P = W / t). The Horsepower Calculator instead derives power from engine torque and RPM, and the Engine Horsepower Calculator estimates power from vehicle weight and quarter-mile trap speed or elapsed time.
Does this handle electrical power?
No. This calculator is scoped to mechanical power from work divided by time. It does not compute electrical power from voltage and current.
Can work be zero?
Yes. Zero work over a positive time is mathematically valid and yields a power of zero.
Why must time be positive?
Power is work divided by time, which is undefined for zero or negative time (division by zero or a meaningless negative duration), so time must be a positive number.