Downpipe lengths calculator
Estimate stock pipe lengths for downpipe runs.
Your measurements
Enter your project values. Your estimate updates as you type.
View your estimateExample values are a starting point. Check product yields and specifications before ordering.
YOUR ESTIMATE
Stock lengths to buy
Whole quantities are rounded up.
How it's calculated
Required length = length per run × runs × (1 + waste ÷ 100). Stock count = required length ÷ stock length, rounded up.
Calculations use consistent units for your selected measurements. The waste allowance is applied once to the measured requirement. Whole purchase quantities are rounded up.
What this estimate includes
Add offsets and bends to required length or estimate them separately. This does not size drainage capacity.
Quantity and arithmetic estimates only. Use project specifications for installation and design requirements.