Radiator Size Calculator

Radiator Size Calculator helps you figure out what size radiator you actually need, without overcomplicating it. You can either get a quick estimate in seconds, or take a bit more time and set up your room properly for a more accurate result. It’s built around typical UK homes, so the numbers you get are practical and useful. == What you get == Free to use • Quick Calculate for fast radiator sizing • Instant BTU and wattage estimates Full Access (one-time purchase) • Guided room setup with step-by-step help • Save multiple rooms • Export your data as text or CSV • More detailed, tailored results