Utilnaro

Work, energy and power

Power, work and time

Calculate average power, work, or elapsed time from the relation between transferred energy and time.

Formula

P=Wt P = W / t

Average power is the work done, or energy transferred, per unit of time.

Power, work and time calculator

What do you want to calculate?

Known values

The result updates automatically.

Result

100 W

Substitution and calculation

P = W / t = 1,000 J / 10 s = 100 W

Symbols and units

SymbolQuantitySISupported units
Paverage powerRate at which work is done or energy is transferred.WW, kW
Wwork or energyTotal work done or energy transferred during the interval.JJ, kJ
telapsed timeDuration of the work or energy transfer.ss, min, h

Formula rearrangements

Calculate power

P = W / t

Calculate work

W = P × t

Calculate time

t = W / P

Worked examples

Average power of a lifting machine

A machine performs 3600 J of work in 30 seconds. Calculate its average power.

  1. 1Step 1: Use P = W / t.
  2. 2Step 2: Substitute W = 3600 J and t = 30 s.
  3. 3Step 3: Divide to obtain 120 W.

Result: 120 W

Work from power and operating time

A 2.4 kW machine operates for 5 minutes. Calculate the transferred energy.

  1. 1Step 1: Convert 2.4 kW to 2400 W and 5 minutes to 300 seconds.
  2. 2Step 2: Use W = P × t.
  3. 3Step 3: Multiply to obtain 720,000 J, or 720 kJ.

Result: 720 kJ

Sources and review