What is the most common roof pitch?

6/12 is the workhorse of suburban housing, with 4/12 common on ranches and 8/12 and up on two-story and traditional styles. Tract builders pick pitch for cost and curb appeal, not for any structural rule.

What is the minimum pitch for asphalt shingles?

4/12 with standard underlayment, or 2/12 with a double layer of felt or a full peel-and-stick membrane. Below 2/12 shingles are not rated at all — that roof needs a membrane or low-slope metal system.

How do I convert pitch to degrees?

Divide the rise by 12 and take the arctangent. 6/12 is arctan(0.5) = 26.6°; 12/12 is exactly 45°. The chart above lists the common conversions so you rarely need the calculator.

What roof pitch is walkable?

Most roofers work 6/12 and below without support, use roof jacks at 7/12–8/12, and require full staging at 9/12 and steeper. For a homeowner without roofing boots and experience, treat anything above 6/12 as not walkable.

What is the slope multiplier for a 6/12 pitch?

1.118. Multiply the footprint by 1.118 to get the sloped roof area, or multiply a level run by 1.118 to get the rafter length. A 2,000 sq ft footprint at 6/12 is about 2,236 sq ft of roof before waste.

Is a 12/12 roof 45 degrees?

Yes, exactly. Rise equals run, so the angle is 45° and the multiplier is 1.414 — the square root of two. The roof surface is 41% larger than the footprint it covers.

Roof Pitch Chart

Roof pitch is the rise over a 12-inch level run — a 6/12 roof climbs 6 inches for every foot it travels sideways. The chart below converts each common pitch into its angle, its area multiplier, and what it means for whoever has to stand on it or shingle it.

Last reviewed 9 Sept 2026

The chart

Pitch is rise over a fixed 12-inch run. The multiplier in the chart converts the flat run into the true sloped length of the rafter — the same math the area conversion uses.

The multiplier is the number that converts footprint into actual roof surface: multiply the flat plan area by it, and you have the sloped area the materials have to cover. It is also the number that converts level run into rafter length.

Pitch	Angle	Multiplier	In practice
1/12	4.8°	1.003	Low-slope only. No shingles — membrane or metal.
2/12	9.5°	1.014	Minimum for shingles, and only with double underlayment or peel-and-stick.
3/12	14.0°	1.031	Shinglable with the same underlayment upgrade.
4/12	18.4°	1.054	Standard minimum for shingles with normal felt. Walkable with care.
5/12	22.6°	1.083	Common ranch pitch. Walkable.
6/12	26.6°	1.118	The workhorse suburban pitch. Walkable in boots.
7/12	30.3°	1.158	Getting steep. Toe boards start making sense.
8/12	33.7°	1.202	Not safely walkable. Staging or roof jacks.
9/12	36.9°	1.250	Staging required. Labor rate climbs.
10/12	39.8°	1.302	Steep. Expect a steep-slope charge on the bid.
12/12	45.0°	1.414	Forty-five degrees. Everything takes longer up there.

The shingle minimums are the numbers people get wrong

Asphalt shingles are rated down to 4/12 with standard underlayment, and down to 2/12 only if the deck gets a double layer of felt or a full peel-and-stick membrane first. Below 2/12, shingles are off the table entirely — the roof is low-slope, and it needs a membrane system like modified bitumen, TPO, or standing-seam metal with a rated seam.

This is not a warranty technicality. Water moves slowly off a 2/12 roof, wind pushes it uphill under the laps, and a shingled 1/12 roof will leak. I have seen exactly one shingled dead-flat porch roof, and it leaked.

If an addition or porch ties into a steeper main roof, the transition pitch is where the detail usually fails. The main roof might be a shinglable 6/12 while the porch settles to 2/12 — different underlayment, different risk, and the bid should show it.

Walkability, staging, and what steep costs

Walkable is a real threshold, not a figure of speech. Most roofers will work a 6/12 roof without anything under their feet. At 7/12 and 8/12 the careful ones set roof jacks and planks. At 9/12 and above, nobody works without staging, and the bid carries a steep-slope charge because every bundle, every nail, and every body moves slower.

That charge is honest money. Steep roofs burn labor at roughly the rate the multiplier climbs — a 12/12 roof is not 41% more expensive than a flat one, but it is noticeably more than the same area at 6/12, and the multiplier understates it.

For a homeowner, walkability matters for a different reason: anything 8/12 or steeper is a ladder-and-binoculars roof. Inspect it from the ground and pay someone for the close look.

Using the multiplier

Footprint area times the multiplier gives sloped roof area; divide by 100 and you have squares. Level run times the multiplier gives the rafter length from wall to ridge — add the overhang separately, since the tail runs past the wall at the same pitch.

The multiplier is just the secant of the angle, which is a fancy way of saying it is the hypotenuse divided by the run. You never need to know that to use the chart. You do need to know that skipping it — bidding a 10/12 roof off the floor plan — underestimates the material by almost a third, and that is the most expensive arithmetic error in residential roofing.

Work out your own number

Ranges are a starting point. Put your own dimensions, materials and region into the calculator and it will show the formula it used.

Open the roof pitch calculator

Frequently asked questions

What is the most common roof pitch?: 6/12 is the workhorse of suburban housing, with 4/12 common on ranches and 8/12 and up on two-story and traditional styles. Tract builders pick pitch for cost and curb appeal, not for any structural rule.
What is the minimum pitch for asphalt shingles?: 4/12 with standard underlayment, or 2/12 with a double layer of felt or a full peel-and-stick membrane. Below 2/12 shingles are not rated at all — that roof needs a membrane or low-slope metal system.
How do I convert pitch to degrees?: Divide the rise by 12 and take the arctangent. 6/12 is arctan(0.5) = 26.6°; 12/12 is exactly 45°. The chart above lists the common conversions so you rarely need the calculator.
What roof pitch is walkable?: Most roofers work 6/12 and below without support, use roof jacks at 7/12–8/12, and require full staging at 9/12 and steeper. For a homeowner without roofing boots and experience, treat anything above 6/12 as not walkable.
What is the slope multiplier for a 6/12 pitch?: 1.118. Multiply the footprint by 1.118 to get the sloped roof area, or multiply a level run by 1.118 to get the rafter length. A 2,000 sq ft footprint at 6/12 is about 2,236 sq ft of roof before waste.
Is a 12/12 roof 45 degrees?: Yes, exactly. Rise equals run, so the angle is 45° and the multiplier is 1.414 — the square root of two. The roof surface is 41% larger than the footprint it covers.