All you need to do is to type in your room measurements, set the correct units and click the "equals" button to obtain the heat output needed to adequately heat your room.

ROOM MEASUREMENTS TAKEN IN:    Feet Metres

LENGTH:        WIDTH:        HEIGHT:

kW of heat output needed.

Whilst accurate the above calculator should be used for guidance only.
When heating a room factors other than size should also be taken into account such as the number of doors and windows and other methods of ventilation.