Roof Pitch Chart
Look up angle, slope percent, multiplier, and materials for every pitch from 1:12 to 24:12.
Roof pitch chart: 1:12 to 24:12
Search by pitch or angle, or filter by class. Each row is one pitch from 1:12 to 24:12.
Rafter length is for a 20-foot building span (10-foot run per side), not your span. Multiplier = √(1 + (pitch/12)²). That is the same number as slope factor and pitch factor below.
What does the row you just found mean?
The left column is pitch as rise:12. Read right for angle, slope percent, area multiplier, and a 20-foot rafter example.
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.
A 6:12 pitch (the most common US residential pitch) has a multiplier of 1.118 — meaning a 1,000 sq ft footprint actually needs 1,118 sq ft of shingles, underlayment, and labor. At 12:12 (45°) the multiplier hits 1.414, so you need 41.4% more material than the footprint suggests.
Use the table below to estimate material orders quickly, or click any row in the interactive chart above to see the multiplier alongside angle and rafter length.
| 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.
What the category badge means
The badge on each row is one of these five classes. It is a shorthand for typical drainage and materials, not a code approval.
Near-level roofs that allow rooftop access and HVAC placement. Require membrane waterproofing systems rated for ponding water.
Gentle slopes common in ranch-style homes. Offer a balance between modern aesthetics and basic water drainage.
The most popular range for residential construction. Balances drainage performance, material compatibility, cost, and walkability.
High-pitched roofs that excel at shedding snow and rain rapidly. Difficult to walk on — professional installation required.
Extreme pitches used for dramatic architectural statements. Requires specialized roofing equipment and safety measures.
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.
- 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.
Roof pitch chart questions
Same-table questions: slope chart vs pitch chart, 24/12, and looking up from degrees.
On this page, yes. Roof slope chart and roof pitch chart point at the same 1:12 to 24:12 table. Pitch is written as rise:12; slope percent is the same ratio as a percentage. Search either name; the row is the same.
24:12 means 24 inches of rise per 12 inches of run, which is 63.4° from horizontal and a multiplier of 2.236. It is on the last row of the table. A-frame walls are often this steep; most houses are not.
You can search the table by angle (try 26 for 6:12). If you need to convert a measured angle into pitch, percent, and 1:N, use the pitch to degrees converter. This page lists whole-inch pitches; it does not replace a converter.