Radiator Size Calculator

Plan your heating properly. Get a quick radiator size or set up your room step by step for a more accurate result.

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