Is a roof slope chart the same as a roof pitch chart?

Yes. A roof slope chart and a roof pitch chart reference the same 1:12 to 24:12 incline table. Roof pitch is written as vertical rise per 12 inches of horizontal run (such as 4:12 or 4/12), while slope percentage expresses that same rise-over-run ratio as a percentage (33.3% for 4/12) and roof angle expresses it in degrees from horizontal (18.4° for 4/12).

What is a 24/12 roof pitch (and what is a 0/12 pitch)?

A 24/12 roof pitch (24:12) rises 24 inches for every 12 inches of horizontal run — a 63.4° angle from horizontal, 200% slope, and a 2.236 pitch multiplier, typically seen on A-frame cabins, mansards, and steeples. At the opposite end, a 0/12 pitch (0° angle, 0% slope, 1.000 multiplier) is dead-level; building codes such as IRC R905 generally require at least 1/4:12 (1.2° or 2% slope) for positive roof drainage.

How do I use a roof pitch degree chart if I only have degrees (like 15°, 30°, or 45°)?

Type your angle into the search box above to filter the closest whole-inch pitch row: a 15 degree roof pitch is closest to 3/12 (14.0°), a 30 degree roof pitch is closest to 7/12 (30.3°), and a 45 degree roof pitch is exactly 12/12 (45.0°). For exact decimal pitches between rows (such as 15.0° = 3.22:12 or 20.0° = 4.37:12), use the dedicated angle converter.

What are the angle and pitch factor for a 4/12, 6/12, and 8/12 roof pitch?

A 4/12 roof pitch is an 18.4° angle (33.3% slope) with a pitch factor (multiplier) of 1.054 (5.4% more area than flat). A 6/12 roof pitch is a 26.6° angle (50.0% slope) with a pitch factor of 1.118 (11.8% extra area). An 8/12 roof pitch is a 33.7° angle (66.7% slope) with a pitch factor of 1.202 (20.2% extra area) and a hip/valley factor of 1.564.

What is the difference between roof pitch multiplier, slope factor, and pitch factor?

For common rafters and roof surface area, all three terms mean the exact same number: √(1 + (Rise ÷ 12)²). Framers usually call it the roof pitch multiplier, shingle suppliers call it the slope factor, and estimating software calls it the roof pitch factor. When estimating hip or valley rafters, pitch factor charts also list a second diagonal column: √(2 + (Rise ÷ 12)²).

What is the minimum roof pitch for asphalt shingles and metal roofing?

Under 2024 IRC Section R905.2.2, asphalt shingles require a minimum 2:12 (2/12) roof pitch; pitches from 2:12 up to 4:12 require double underlayment, while 4:12 and steeper use standard single underlayment. Under IRC R905.10.2, lapped non-soldered metal roof panels require at least 3:12 (or 1/2:12 with lap sealant), and standing-seam metal roofs can go down to 1/4:12. Always verify with the manufacturer's installation instructions and local building code.

What is the average roof pitch on a residential house?

Most conventional US residential houses use a standard roof pitch between 4/12 and 8/12 (18.4° to 33.7°). Within that range, 6/12 (26.6°) is the classic benchmark for gable and hip homes because it sheds rain and snow reliably, provides usable attic height, and remains walkable for roofers (pitches above 7/12 or 8/12 generally require roof jacks and harnesses).

How do I find my roof pitch if I don't know which row to use?

Hold a 12-inch carpenter's level (or mark 12 inches on a longer level) horizontally against the roof surface or an exposed attic rafter, then measure straight up from the 12-inch mark to the roof plane in inches. That vertical measurement is your X in X:12.

Roof Pitch Chart: 1:12 to 24:12 Angles & Pitch Factors

Roof Pitch & Slope Chart: 1:12 to 24:12 Reference Table

Search by pitch (e.g. 4/12), angle in degrees (e.g. 26.6°), slope %, or pitch factor (e.g. 1.118), or filter by slope category.

Pitch	Angle	Slope %	Multiplier	Rafter (20ft)	Category	Materials
1:12(1/12)	4.8°	8.3%	1.003	20.1 ft	Flat Roof	Built-Up Roofing (BUR), Single-Ply Membrane (TPO/EPDM), Modified Bitumen
2:12(2/12)	9.5°	16.7%	1.014	20.3 ft	Flat Roof	Built-Up Roofing (BUR), Single-Ply Membrane (TPO/EPDM), Modified Bitumen
3:12(3/12)	14.0°	25.0%	1.031	20.6 ft	Low Slope	Standing Seam Metal, Corrugated Metal Panels, Asphalt Shingles
4:12(4/12)	18.4°	33.3%	1.054	21.1 ft	Low Slope	Standing Seam Metal, Corrugated Metal Panels, Asphalt Shingles
5:12(5/12)	22.6°	41.7%	1.083	21.7 ft	Standard	Standing Seam Metal, Corrugated Metal Panels, Asphalt Shingles
6:12(6/12)	26.6°	50.0%	1.118	22.4 ft	Standard	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
7:12(7/12)	30.3°	58.3%	1.158	23.2 ft	Standard	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
8:12(8/12)	33.7°	66.7%	1.202	24.0 ft	Standard	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
9:12(9/12)	36.9°	75.0%	1.250	25.0 ft	Standard	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
10:12(10/12)	39.8°	83.3%	1.302	26.0 ft	Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
11:12(11/12)	42.5°	91.7%	1.357	27.1 ft	Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
12:12(12/12)	45.0°	100.0%	1.414	28.3 ft	Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
13:12(13/12)	47.3°	108.3%	1.474	29.5 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
14:12(14/12)	49.4°	116.7%	1.537	30.7 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
15:12(15/12)	51.3°	125.0%	1.601	32.0 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
16:12(16/12)	53.1°	133.3%	1.667	33.3 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
17:12(17/12)	54.8°	141.7%	1.734	34.7 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
18:12(18/12)	56.3°	150.0%	1.803	36.1 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
19:12(19/12)	57.7°	158.3%	1.873	37.5 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
20:12(20/12)	59.0°	166.7%	1.944	38.9 ft	Very Steep	Corrugated Metal Panels, Asphalt Shingles, Wood Shakes
21:12(21/12)	60.3°	175.0%	2.016	40.3 ft	Very Steep	Corrugated Metal Panels, Wood Shakes, Clay / Concrete Tile
22:12(22/12)	61.4°	183.3%	2.088	41.8 ft	Very Steep	Corrugated Metal Panels, Wood Shakes, Clay / Concrete Tile
23:12(23/12)	62.4°	191.7%	2.162	43.2 ft	Very Steep	Corrugated Metal Panels, Wood Shakes, Clay / Concrete Tile
24:12(24/12)	63.4°	200.0%	2.236	44.7 ft	Very Steep	Corrugated Metal Panels, Wood Shakes, Clay / Concrete Tile

Baseline 0:12 (dead-flat) = 0.0° angle, 0.0% slope, 1.000 multiplier. Rafter (20ft) assumes a 20-foot building span (10-foot horizontal run per side). Multiplier = √(1 + (pitch/12)²), identical to slope factor and common pitch factor below.

How to Read the Roof Pitch Conversion & Comparison Chart

Each row converts a whole-inch X:12 (X/12) roof pitch into its horizontal angle in degrees, slope percentage, area multiplier, and a 20-foot span rafter benchmark.

What each column is

Pitch: Inches of rise per 12 inches of horizontal run. 6:12 rises 6 inches in every foot of run.
Angle: Degrees from horizontal, not the complementary cut on a speed square.
Slope %: (rise ÷ 12) × 100. A 6:12 pitch is 50% slope, not 26.6%.
Multiplier: Footprint × this number = sloped roof area. Same value as slope factor and pitch factor.
Rafter (20ft): Example for a 20-foot building span (10-foot run each side). It is not the length for your house.
Category / materials: A shorthand class and typical products for that pitch. Confirm with the manufacturer and local code.

Check a 6:12 row

6:12 is 26.6° from horizontal, 50% slope, multiplier 1.118. A 1,000 sq ft footprint needs about 1,118 sq ft of roofing. The 20-foot example rafter is 22.4 ft.

When this chart is the wrong tool

Half pitches such as 4.5:12, or 0.5:12, are not in this table. Use the roof slope calculator for a decimal rise.
If you have degrees or percent and need X:12, convert on the pitch to degrees converter. This table lists whole-inch pitches.
If you do not know the pitch yet, measure roof pitch first, then come back to look it up.
Rafter length for your span, overhang, or birdsmouth is the rafter length calculator, not the 20-foot example column.

Roof Pitch Multiplier Chart

The pitch multiplier converts a flat plan-view area into the true sloped roof surface area. It's the single most useful number on this chart for ordering materials.

Pitch multiplier = √(1 + (pitch / 12)²). A flat 0:12 roof has a multiplier of 1.000 — every square foot of footprint equals one square foot of roof. As pitch rises, the multiplier grows because the same footprint covers a longer sloped surface.

Common residential multipliers to remember: 4/12 = 1.054 (5.4% extra area), 6/12 = 1.118 (11.8% extra area — a 1,000 sq ft footprint needs 1,118 sq ft of roofing), 8/12 = 1.202 (20.2% extra), and 12/12 (45°) = 1.414 (41.4% extra material).

To convert your plan footprint into roofing squares (1 square = 100 sq ft): Roofing Squares = (Footprint sq ft × Pitch Multiplier) ÷ 100, then add 10%–15% for starter courses, ridge caps, and cutting waste.

Pitch (X:12)	Multiplier	1,000 sq ft → Roof Area
1 : 12	1.003	1003 sq ft
2 : 12	1.014	1014 sq ft
3 : 12	1.031	1031 sq ft
4 : 12	1.054	1054 sq ft
5 : 12	1.083	1083 sq ft
6 : 12	1.118	1118 sq ft
7 : 12	1.158	1158 sq ft
8 : 12	1.202	1202 sq ft
9 : 12	1.250	1250 sq ft
10 : 12	1.302	1302 sq ft
11 : 12	1.357	1357 sq ft
12 : 12	1.414	1414 sq ft

Multiplier values rounded to 3 decimals. Example column assumes a 1,000 sq ft building footprint; multiply by your actual footprint to estimate true roof area.

Slope Factor Chart — Same Number, Different Name

Slope factor and pitch multiplier are the same value expressed in different industry vocabularies. Roofers, framers, and material suppliers may call it either — knowing both prevents costly miscommunication on quotes.

Slope factor = √(1 + (pitch / 12)²) — identical formula to pitch multiplier. Roofing manufacturers and shingle bundle calculators typically use "slope factor"; framing carpenters and rafter tables often say "pitch multiplier". They are interchangeable.

Some material suppliers also express slope factor as a percentage of the flat plan area added by the slope. A 6:12 pitch with factor 1.118 means roof area is 11.8% larger than the footprint; a 12:12 pitch (factor 1.414) means 41.4% larger.

The table below shows slope factor as both a decimal and as the percentage of extra material needed compared to a flat roof of the same footprint.

Pitch (X:12)	Slope Factor	Extra Material vs Flat
1 : 12	1.003	0.3%
2 : 12	1.014	1.4%
3 : 12	1.031	3.1%
4 : 12	1.054	5.4%
5 : 12	1.083	8.3%
6 : 12	1.118	11.8%
7 : 12	1.158	15.8%
8 : 12	1.202	20.2%
9 : 12	1.250	25.0%
10 : 12	1.302	30.2%
11 : 12	1.357	35.7%
12 : 12	1.414	41.4%

Slope factor is dimensionless. Extra Material % = (slope factor − 1) × 100, rounded to one decimal. Use this when comparing supplier quotes that mix vocabularies.

Roof Pitch Factor Chart: Common, Hip & Valley Factors

"Roof pitch factor" is the estimator's name for the multiplier above — but a full pitch factor chart adds a second column roofers need: the hip and valley factor for diagonal rafters. Here is the complete table from 1/12 to 24/12.

The roof pitch factor converts a flat, plan-view measurement into the true length along the slope: pitch factor = √(1 + (pitch ÷ 12)²). It is the exact same number as the pitch multiplier and slope factor above — estimating guides and takeoff software simply prefer the word "factor".

For example, the 8/12 pitch factor is 1.202. A wall-to-ridge plan distance of 20 ft means 20 × 1.202 ≈ 24 ft of actual slope length, and a 1,000 sq ft footprint needs about 1,202 sq ft of roofing material.

The hip & valley factor does the same job for the diagonal rafters of a hip roof: hip/valley factor = √(2 + (pitch ÷ 12)²). Multiply it by the common rafter's horizontal run to get the hip or valley rafter length.

Pitch (X:12)	Pitch Factor	Hip & Valley Factor
1 : 12	1.003	1.417
2 : 12	1.014	1.424
3 : 12	1.031	1.436
4 : 12	1.054	1.453
5 : 12	1.083	1.474
6 : 12	1.118	1.500
7 : 12	1.158	1.530
8 : 12	1.202	1.563
9 : 12	1.250	1.601
10 : 12	1.302	1.641
11 : 12	1.357	1.685
12 : 12	1.414	1.732
13 : 12	1.474	1.781
14 : 12	1.537	1.833
15 : 12	1.601	1.887
16 : 12	1.667	1.944
17 : 12	1.734	2.002
18 : 12	1.803	2.062
19 : 12	1.873	2.123
20 : 12	1.944	2.186
21 : 12	2.016	2.250
22 : 12	2.088	2.315
23 : 12	2.162	2.382
24 : 12	2.236	2.449

Both factors are per foot of horizontal run, rounded to 3 decimals. Pitch factor = √(1 + (pitch/12)²); hip & valley factor = √(2 + (pitch/12)²). The pitch factor column matches the multiplier and slope factor tables above — same number, estimator vocabulary.

Need full rafter math — overhang, ridge deduction, birdsmouth? Use the Rafter Length Calculator →

Roof Pitch Diagram & Common Roof Pitches Explained (1/12 to 24/12)

Compare the five roof slope classes on the profile diagrams below, then review the breakdown of the most common residential and commercial pitches from 1/12 to 24/12.

Flat Roof0–2:12 (0–9.5°)

Near-level roofs that allow rooftop access and HVAC placement. Require membrane waterproofing systems rated for ponding water.

Commercial buildings, modern homes, garages

TPO, EPDM, Modified Bitumen, BUR

Low Slope2–4:12 (9.5–18.4°)

Gentle slopes common in ranch-style homes. Offer a balance between modern aesthetics and basic water drainage.

Ranch homes, sheds, lean-to additions

Standing Seam Metal, Shingles (with underlayment)

Standard4–9:12 (18.4–36.9°)

The most popular range for residential construction. Balances drainage performance, material compatibility, cost, and walkability.

Most residential homes, colonial, Cape Cod

Asphalt Shingles, Metal, Clay Tile

Steep9–12:12 (36.9–45°)

High-pitched roofs that excel at shedding snow and rain rapidly. Difficult to walk on — professional installation required.

Tudor style, Victorian, snow country homes

Slate, Wood Shakes, Premium Shingles

Very Steep12+:12 (45°+)

Extreme pitches used for dramatic architectural statements. Requires specialized roofing equipment and safety measures.

A-frames, mansard roofs, church steeples

Slate, Standing Seam Metal, Specialty Tile

Common Roof Pitches: Angles, Pitch Factors & Typical Uses

Quick engineering reference for the most-searched X/12 roof pitches, degree equivalents (15°, 30°, 45°), and slope factors:

1/12 & 2/12 Roof Pitch

4.8°–9.5° · 8.3%–16.7% · Factor 1.003–1.014

1/12 (4.8°) requires single-ply membranes (TPO/EPDM) or standing-seam metal. 2/12 (9.5°) is the absolute minimum pitch for asphalt shingles under IRC R905.2.2 and requires a double-layer underlayment.

3/12 Roof Pitch (~15° Roof)

14.0° · 25.0% slope · Factor 1.031

Common on porch covers, carports, and lean-to shed additions. Sits just below 15° (an exact 15° roof is 3.22:12). Shingles on a 3/12 roof still require special low-slope underlayment per IRC R905.2.2.

4/12 Roof Pitch

18.4° · 33.3% slope · Factor 1.054

The standard minimum pitch for single-layer asphalt shingle underlayment, clay/concrete tile, and wood shakes. Widely used on ranch houses, garages, and low-profile suburban homes.

5/12 Roof Pitch

22.6° · 41.7% slope · Factor 1.083

Comfortable walking slope for roofers without steep-slope staging. Popular on contemporary gables, craftsman bungalows, and patio roofs where moderate attic clearance is needed.

6/12 Roof Pitch

26.6° · 50.0% slope · Factor 1.118

The benchmark US residential roof pitch. Rises half an inch per inch of run (50% slope), adds 11.8% to flat footprint area, and balances snow shedding, attic headroom, and walkable installation.

7/12 (~30° Roof) & 8/12 Pitch

30.3°–33.7° · 58.3%–66.7% · Factor 1.158–1.202

7/12 (30.3°) is the closest whole-inch match to a 30° roof pitch and marks the threshold where roofers transition to toe boards and harnesses. 8/12 (33.7°, factor 1.202) is classic on colonial and custom homes.

9/12 & 10/12 Roof Pitch

36.9°–39.8° · 75.0%–83.3% · Factor 1.250–1.302

Steep architectural pitches (9/12 has an exact 1.250 3-4-5 triangle multiplier) used on Cape Cod, Tudor, and high-snowfall roofs to shed heavy snow loads and create vaulted attic rooms.

12/12 Roof Pitch (45° Roof)

45.0° · 100.0% slope · Factor 1.414

Vertical rise equals horizontal run (exact 45° angle). Requires 41.4% more roofing material than the flat footprint (√2 = 1.414) and full steep-slope safety rigging.

14/12 to 24/12 Roof Pitch

49.4°–63.4° · 116.7%–200% · Factor 1.537–2.236

Very steep specialty framing: 14/12 (49.4°), 16/12 (53.1°), 18/12 (56.3°), up to 24/12 (63.4° angle, 2.236 multiplier). Reserved for A-frame cabins, Victorian turrets, mansards, and church steeples.

You have a row. What next?

Write the numbers down, or leave this page if you need a calculation this table does not do.

Pitch, angle, slope percent, and multiplier are on the row. The 1,000 sq ft examples in the multiplier tables show how that number turns a footprint into roof area.
To run the same pitch with your own span or area, use the roof slope calculator.
To calculate exact common rafter length with building span, ridge board deduction, and eave overhang, use the rafter length calculator.
Framing a single-slope shed, porch, or addition? Calculate high-wall and low-wall drop on the lean-to roof pitch calculator.
If you do not have a pitch yet, measure roof pitch first, then look the value up here.
To convert an angle or percent into X:12, use the pitch to degrees converter.
A low-slope drainage fall in inches or millimeters is a different job. Use the flat roof slope calculator.
Estimating roofing squares or shingle bundles? Multiply your flat building footprint (sq ft) by the row's Pitch Multiplier, divide by 100 to get roofing squares, and add 10%–15% for waste.

Roof Pitch Chart