Gutter length calculator
How much gutter does the house need?
Add the length of each roof edge, pick a section size, and see the sections, downspouts, hangers and end caps to buy. The bars show how each edge adds up.
Roof edges (eave runs), in feet
--
How the count is built
Add up the length of every roof edge that needs gutter, then add your waste allowance and divide by the section length. The result is rounded up to whole sections. Downspouts are counted by dividing the total length by your spacing, and hangers by dividing the length in inches by the hanger spacing.
- Section length depends on the product you choose. Ten-foot sections are common, but check what your supplier stocks.
- Downspouts are often spaced about 30 to 40 feet apart, but roof size, rainfall and local rules change that. Use the spacing that matches your building code or installer’s advice.
- Hangers are often spaced about every two feet, though some systems use other spacings. Check the manufacturer’s instructions.
Before you order
Measure the eaves at the roof edge, not the wall, and allow for corners and outlets. The count here is a planning estimate. Confirm the final numbers with a supplier or installer, and check fascia condition before you fit new gutter.
Check the home before the rain
Fix the things that matter, room by room
RoomMend: Safer Home Plans is a free app for tracking home safety fixes room by room, in your own home or a parent’s. Setup takes one step: choose an apartment, one-floor or two-floor layout, then edit the rooms.
Logging an issue takes about three taps, with suggested fixes, optional photos and a timeframe. The home screen always shows your next task, and the app works privately and offline, with no account or ads.
Get RoomMend on the App StoreThe core features are free. RoomMend Plus is a one-time $19.99 purchase that adds extras such as more homes and a whole-home PDF. Requires iOS 18 or later. Details checked against the App Store listing on November 10, 2026.
Publisher disclosure: Honest Little Apps publishes both RoomMend and this page. This is not an independent review. This page is a separate web companion, not a feature of the app. This gutter calculator is a free web tool from the same publisher. It is a rough planning count, not a home inspection or a quote, and it does not verify completed work.
Gutter questions
How many gutter sections do I need?
Add your roof edges, add the waste allowance and divide by the section length, rounding up. Two edges of 40 feet and 30 feet make 70 feet. With 10 percent waste that is 77 feet, so eight 10-foot sections.
How many downspouts do I need?
A common rule of thumb is one downspout for every 30 to 40 feet of gutter. The calculator uses the spacing you enter, which you can change to match your roof and local advice.
Do I need to count corners?
Corners and end caps are usually bought separately. The calculator counts two end caps for each edge, and you should add elbows and outlets to your list for each downspout.
Is this a home inspection?
No. It counts what to buy for planning. For damage, slope, fascia or drainage problems, ask a qualified roofer or contractor to look.
Useful for someone else?
Share the public page. Nothing you entered is included.
Open the public link