Gutter Length Calculator
Enter your roofline perimeter and desired downspout spacing to estimate gutter and downspout needs.
Gutter Length Calculator
Estimate the total linear feet of gutter and number of downspouts needed for a home.
This is an estimate for general informational purposes only, not a professional quote. Actual downspout placement depends on roof slope, valleys, and local drainage requirements — consult a gutter installer for a precise layout.
Gutters generally run along the entire eave length of a roof, with downspouts placed at intervals to properly drain water — this calculator estimates both from your roofline perimeter.
Example
- With the default values shown above, this calculator returns: Total Gutter Length Needed ≈ 150; Downspouts Needed ≈ 4.3.
Frequently Asked Questions
How far apart should downspouts be?
A common guideline is one downspout for every 30-40 feet of gutter, though steeper roofs or heavy rainfall areas may need closer spacing to handle water volume.
Does gutter length equal roofline length exactly?
Generally yes, for a straightforward roofline — but complex rooflines with multiple sections may need gutters measured separately for each section and then summed.