Radiant Floor Tubing Calculator
Estimate hydronic radiant-floor tubing from heated area, tube spacing, perimeter allowance, loop-length limit, waste and coil size.
Default project preview
2 coils
Base grid length
1,200 ft
Design tubing length
1,344 ft
Average loop length
269 ft
Purchased tubing
2,000 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.
Heated floor area
Enter this project assumption in ft². The current imperial default is 1200 ft².
Tube spacing
Enter this project assumption in in. The current imperial default is 12 in.
Headers, turns and manifold allowance
Enter this project assumption in %. The current imperial default is 12 %. Minimum: 0. Maximum: 50.
Cut and spare allowance
Enter this project assumption in %. The current imperial default is 8 %. Minimum: 0. Maximum: 50.
Maximum planned loop length
Enter this project assumption in ft. The current imperial default is 300 ft.
Tubing coil length
Enter this project assumption in ft. The current imperial default is 1000 ft.
Price per coil
Enter this project assumption in a unitless value. The current imperial default is 520. Minimum: 0.
How to read the outputs
Base grid length
heated area ÷ tube spacing. Default preview: 1,200 ft.
Design tubing length
includes turns and manifold runs. Default preview: 1,344 ft.
Average loop length
design length ÷ loops. Default preview: 269 ft.
Purchased tubing
full coils. Default preview: 2,000 ft.
Unused purchased tubing
coil rounding. Default preview: 548 ft.
Tubing cost
tubing coils only. Default preview: $1,040.00.
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 ÷ tube spacing. Add perimeter/manifold allowance, divide by maximum loop length for circuit count, then add waste and round to full coils.
Related tools
Continue planning the project
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Radiant Floor Tubing Calculator questions
Why does area divided by spacing estimate tubing length?+
Parallel tubing rows approximately cover one strip of floor equal to the spacing for each unit of tube length.
Can every room use the same spacing?+
No. Heat loss, floor covering and perimeter zones may require different spacing or water temperature.
Does this size the circulator or boiler?+
No. Flow, pressure drop and heat output require a complete hydronic design.