Radiant Floor Heating Calculator
Estimate radiant-floor heat output, tubing length, loop count and material cost from heated area, coverage percentage, tubing spacing, routing allowance and maximum loop length.
Default project preview
6 loops
Heated floor area
1,080 ft²
Planning heat output
27,000 BTU/h
Tubing before allowance
1,440 ft
Average tubing per loop
264 ft
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Total floor area
Enter this project assumption in ft². The current imperial default is 1200 ft².
Heated floor percentage
Enter this project assumption in %. The current imperial default is 90 %. Minimum: 1. Maximum: 100.
Planning heat output
Enter this project assumption in BTU/h·ft². The current imperial default is 25 BTU/h·ft².
Tubing spacing
Enter this project assumption in in. The current imperial default is 9 in.
Routing and leader allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 50.
Maximum tubing per loop
Enter this project assumption in ft. The current imperial default is 300 ft.
Tubing price
Enter this project assumption in per ft. The current imperial default is 0.75 per ft. Minimum: 0.
Manifold and loop hardware per loop
Enter this project assumption in a unitless value. The current imperial default is 85. Minimum: 0.
How to read the outputs
Heated floor area
90% of total area. Default preview: 1,080 ft².
Planning heat output
entered area output rate. Default preview: 27,000 BTU/h.
Tubing before allowance
area divided by spacing. Default preview: 1,440 ft.
Average tubing per loop
evenly distributed estimate. Default preview: 264 ft.
Equivalent heat output
thermal output equivalent. Default preview: 7.91 kW.
Planning material cost
tubing and entered loop hardware. Default preview: $1,698.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Base tubing length ≈ heated area ÷ tubing spacing. Routing allowance is added, then total tubing is divided by maximum loop length and rounded up. Heat output = heated area × entered output rate.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Radiant Floor Heating Calculator questions
Why exclude some floor area?+
Permanent cabinets, tubs and other areas may not receive tubing, depending on the system design.
Does shorter spacing increase tubing length?+
Yes. Closer spacing places more tubing in the same floor area.
Does this size the boiler or heat pump?+
No. Equipment sizing requires a room-by-room heat-loss calculation and system design.