Radiator BTU Calculator

Estimate room heat requirement in BTU using room dimensions and a simple heat-load factor.

Radiator BTU for a 7.2m by 2.4m room at 2.5m high

For a room measuring 7.2 metres by 2.4 metres with a height of 2.5 metres, this estimate gives the required radiator BTU output using the default heat factor below.

Room volume43.20 m³
Heat factor153 BTU/m³
Required output6,610 BTU

Room length (m)

Room width (m)

Room height (m)

Heat factor (BTU per m³)

Results - Radiator BTU Calculator

Room volume43.20 m³
Heat factor153 BTU/m³
Required output6,610 BTU

BTU estimate notes

This is a quick sizing guide based on room volume and a standard domestic heat factor. It is useful for early-stage product selection, not final heating design.

Frequently asked questions

The Radiator BTU Calculator gives a quick estimate for a project sized at 7.2m by 2.4m by 2.5m using the default assumptions shown on the page.

For most jobs you will need room length, width and height. The calculator then uses those figures to estimate the materials shown in the results.

A small wastage allowance is often sensible because cuts, breakages, uneven ground and product differences can affect the final quantity needed.

Yes, the calculator is set up for typical UK-style measurements and practical estimating assumptions, but final quantities should still be checked before ordering.

It gives a practical starting point for radiator sizing, but insulation levels, window area and room use should still be checked before buying.