PEX Length Calculator

Calculate the total PEX tubing to buy for a set of supply runs, including a waste allowance.

PEX coil
TOTAL PEX
— ft
to purchase

Usage Tip

Each fixture usually needs a hot and a cold run. A 10-20% waste allowance is typical.

THE MATH
total = runs × length × (1 + extra%)
Where: runs = number of supply lines  •  length = average run
• Round up to the next standard coil
• Waste allowance covers bends and cuts
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.