BTU Calculator

BTU Calculator — Size Your Radiators with Confidence Stop guessing. BTU Calculator uses the UK standard heat-loss formula to tell you exactly how powerful a radiator you need for any room in your home. HOW IT WORKS Enter your room dimensions and a few details about the room's construction — wall type, glazing, what's above and below the room, and how many external walls are exposed. The app calculates heat loss through every surface and accounts for air changes, then adds a 15% safety margin t