PEX Tubing Length Calculator
Estimate PEX tubing for home-run or measured branch layouts using cold and hot outlet counts, average run length, recirculation length, waste and coil size.
Default project preview
5 coils
Fixture-run tubing
966 ft
Hot-water runs
9
Cold-water runs
14
Purchased tubing
1,500 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.
Cold-water outlet runs
Enter this project assumption in a unitless value. The current imperial default is 14. Minimum: 0.
Hot-water outlet runs
Enter this project assumption in a unitless value. The current imperial default is 9. Minimum: 0.
Average manifold or branch run length
Enter this project assumption in ft. The current imperial default is 42 ft.
Hot-water recirculation or service loop
Enter this project assumption in ft. The current imperial default is 80 ft. Minimum: 0.
Additional mains or distribution length
Enter this project assumption in ft. The current imperial default is 60 ft. Minimum: 0.
Routing and connection allowance
Enter this project assumption in %. The current imperial default is 15 %. Minimum: 0. Maximum: 50.
Tubing length per coil
Enter this project assumption in ft. The current imperial default is 300 ft.
Price per coil
Enter this project assumption in a unitless value. The current imperial default is 118. Minimum: 0.
How to read the outputs
Fixture-run tubing
23 total outlet runs. Default preview: 966 ft.
Hot-water runs
378 ft. Default preview: 9.
Cold-water runs
588 ft. Default preview: 14.
Purchased tubing
300 ft per coil. Default preview: 1,500 ft.
Unused purchased tubing
full-coil rounding. Default preview: 228.1 ft.
Tubing cost
tubing coils only. Default preview: $590.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Fixture tubing = (cold runs + hot runs) × average run length. Add recirculation and mains, apply allowance, then round to full coils.
Reviewed project guidance
How to use this estimate in a real project
Last reviewed: July 30, 2026
Use the PEX Tubing Length Calculator to estimate a planning quantity from verified zone area, tube spacing, lead lengths and loop limit. It supports scope comparison, purchasing and operating-cost planning, but it does not select equipment, approve code compliance or replace project-specific design.
Calculation steps
- 1Measure or obtain each design input from the actual project and keep one consistent unit system.
- 2Enter zone area, tube spacing, lead lengths and loop limit using product data or approved design information rather than generic nominal values.
- 3Review the unrounded engineering or usage result before applying allowances, duty cycle, efficiency or tariff assumptions.
- 4Apply each adjustment once, then round only the final purchasing, equipment-count or scheduling output.
Worked numerical example
A 600 ft² radiant zone at 12 in spacing needs roughly 600 ft of active tubing before adding manifold leads; splitting it into three loops keeps each near 200 ft plus leads.
Purchasing and rounding
Purchase tubing by total active length plus measured supply/return leads, then divide into loops that respect the design maximum length. Do not hide excessive loop length inside a waste allowance.
Interpret the result
Spacing controls approximate tubing density, while loop length controls hydraulic resistance. The quantity estimate does not establish flow rate, water temperature or heating capacity.
Page-specific assumptions
- Inputs describe the actual connected system or measured project scope.
- One operating condition, product rating and unit system are used per calculation.
- Allowances and efficiency losses are not already embedded in the entered values.
- Code, health, structural, electrical and hydraulic requirements are verified independently.
Common mistakes
- Using nominal equipment ratings instead of delivered performance at design conditions.
- Mixing instantaneous flow or power with daily or annual energy.
- Applying the same allowance more than once.
- Treating a quantity or cost estimate as equipment selection or professional approval.
Primary and technical references
BuildMeter provides planning estimates, not engineering, architectural, electrical, mechanical, plumbing, permit or code approval. Review the methodology and verify final decisions with product documentation and qualified professionals.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
PEX Tubing Length Calculator questions
Can hot and cold tubing be combined in one order?+
Only when the same size and product are used. Separate colors, diameters or barrier types should be calculated separately.
Should fitting takeoffs be included?+
This calculator covers tubing length only. Manifolds, fittings, supports, sleeves and valves need a separate schedule.
Is average run length accurate enough?+
It is useful early in planning. A route-by-route takeoff from drawings or field measurements is more accurate before purchasing.