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Calculate Gutter Size for Your Roof

Built by Kevin Glover · @gloverbuilds · Verified formula

Size gutters and downspouts based on roof area and rainfall intensity. Prevent overflow and foundation damage.

📅 Updated April 2026 ✅ Formula verified 📖 4 min read 🆓 Free · No sign-up

In this article

Gutter Sizing Basics
Downspout Placement

Dimensionierung

Wohnhaus: 100er oder 125er Dachrinne. 1 Fallrohr pro 10-12 m Rinne. Verlängerungsboegen: Wasser min. 1,5 m vom Fundament ableiten. Eine Regenwasser-Versickerungsanlage kann in vielen Kommunen die Niederschlagswassergebuehr sparen (50-200 €/Jahr).

Regenwassernutzung

In Deutschland zunehmend beliebt: Zisterne fuer Gartenbewässerung. 1.000-3.000 € fuer unterirdische Zisterne. Bei 800 mm Niederschlag und 100 m² Dach: 72.000 Liter/Jahr nutzbar. Einige Kommunen gewaehren IPTU-aehnliche Gebuehrenbefreiung.

⚡ CalcWolf Insight

Foundation damage from poor drainage costs $5,000-30,000 to repair. Properly sized gutters and downspouts with extensions cost $1,500-3,000 installed. This is one of the highest-ROI home improvements — protecting your foundation protects your largest investment. Check your gutters during the next heavy rain and note any overflow points.

Frequently asked questions

Welche Rinnengroesse?▾

Einfamilienhaus: 100-125er Nennweite. 1 Fallrohr pro 10-12 m.

Regenwasser nutzen?▾

Zisterne fuer Garten: 1.000-3.000 €. Spart Trinkwasser und ggf. Niederschlagsgebuehr.

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Kevin Glover · @gloverbuilds

Founder, CalcWolf · GLVTS · Blickr

All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →