UFH Coverage Area Calculator

Works out the actual heated floor area for underfloor heating once fixed kitchen units, baths and built-ins are taken out, and the coverage percentage. It runs entirely in your browser and shows the working, so you can check every step against your own figures.

How the ufh coverage area calculator works

The heated area is the room area minus the footprint of fitted units, baths and other built-ins you would not pipe under. Dividing that by the room area gives the coverage percentage — how much of the floor actually carries pipe. That heated area, not the gross room area, is what drives the real pipe length and heat output.

What you enter

Enter the room area and the area of fixed units to exclude; the calculator returns the heated area and coverage percentage. Every field is editable, and the result recalculates the moment you change a value.

Reading the result

Feed the heated area into the pipe-length tool for an accurate material order. Low coverage in a room packed with units may mean underfloor heating alone cannot meet the heat demand — a check worth doing early.

Safe by design

This tool sizes pipe, manifold, coverage and cost. It never sets flow temperatures or heat-source settings — commissioning the system is a qualified heating engineer’s job.

Assumptions and limits

This subtracts a fixed-unit area you supply. It does not judge whether the remaining coverage delivers enough heat — that depends on the room’s heat loss and the floor construction, which a heat-loss calculation resolves.

Using it with the rest of BuildMetricLab

This calculator is one step in planning the job. Pair it with the related tools in this category and across BuildMetricLab to go from a single figure to a full costed plan — a sizing figure feeds a cost estimate, a cost estimate feeds a project budget, and each result carries straight into the next tool. Every BuildMetricLab tool runs entirely in your browser — no sign-up, nothing sent to a server, and the formula is shown on the page so the maths can be audited.