The envelope
Gutter Calculator
Enter the total length of roofline you're guttering. Gutter comes in 10-foot sections, and you generally want a downspout for about every 35 feet of run.
At a glance
- Section length
- 10 ft
- Downspouts
- 1 per 35 ft
10 10 ft sections
+ 3 downspouts
One downspout per ~35 feet is a rule of thumb; long runs and big roofs need more. Add end caps, corners and hangers to your parts list.
The envelope
The envelope works as one system
A roof that sheds fine into gutters that overflow still rots the fascia underneath. When one part is due, it is worth pricing the parts next to it at the same time.
How this is worked out
No hidden fudge factor. This is the whole calculation.
- Your run is divided by the 10 foot section length and rounded up, giving the 10 ft sections.
- One downspout is added for every 35 feet of run.
Common questions
- How much gutter do I need?
- Enter the total length of roofline you're guttering. Gutter comes in 10-foot sections, and you generally want a downspout for about every 35 feet of run. Enter your measurements above and this calculator gives you the amount, including a waste allowance where it applies.