Convert watt hour to erg

The watt (W) is a unit of power, the rate at which energy is used or produced. The watt-hour (Wh) is a unit of energy, one watt sustained for one hour, and is what this page converts: a 2 kW heater running for 3 hours uses 6 kWh, and an electricity bill counts kWh. 'Watts per hour' (W/h) would be a rate of change of power, is rarely needed, and is not the same thing as a watt-hour.

The centimetre-gram-second system preceded the SI and its units linger in physics: the dyne is the force that accelerates one gram at 1 cm/s² (10⁻⁵ N), and the erg the work of one dyne over one centimetre (10⁻⁷ J), about the energy of a mosquito's wing beat. Astrophysics still writes luminosities in erg/s (the Sun: 3.8 × 10³³ erg/s), and surface tension is often quoted in dyn/cm, which equals mN/m.