Roof Pitch to Angle Chart: Degrees for Every Pitch (4/12, 6/12 and More)

The x/12 pitch ratio is the language of the roofing trade, but degrees is the language of geometry, solar design, and any tool with a protractor scale. This page bridges the two. Bookmark the chart, then read on for the reasoning so you can convert any value with confidence, or confirm it instantly in the Roof Pitch Calculator.

The full roof pitch to angle chart

This table lists every whole-number pitch from 1/12 to 24/12 with its exact angle in degrees (rounded to two decimals) and its slope as a percentage. These are the values the calculator uses, computed with the arctangent function described further down.

A few landmarks are worth memorising because they come up constantly. A 12/12 pitch is exactly 45 degrees, the point where rise equals run. A 6/12 pitch, one of the most common residential slopes, is 26.57 degrees. And the shift from “conventional” to “steep” happens around 8/12 to 9/12, which is also roughly where a roof stops being safely walkable, a threshold covered in the walkable roof pitch guide.

How to read the chart

Reading the chart is a matter of matching your known value to the right column. If you have measured a pitch (say 7/12) and need the angle, find 7/12 in the first column and read across to 30.26 degrees. If a document gives you an angle and you need the nearest pitch, scan the degrees column for the closest value and read back to the pitch. Because real roofs are built to whole-number pitches, an angle that falls between two chart rows almost always rounds to the nearer standard pitch.

If you arrived here after measuring your own roof and are not fully sure of the reading, the companion guide how to calculate roof pitch walks through every measuring method, and roof pitch ratios explained shows what each ratio means in practice. Getting the pitch right first is what makes the angle lookup meaningful.

Angles for the most-searched pitches

These are the specific pitches people look up most often, pulled out so you do not have to scan the whole table. Each is the exact angle a builder or solar installer would use.

Notice how each step from one pitch to the next adds only a few degrees at the shallow end but the increments feel bigger visually as they climb. That is because the tangent relationship is not linear; equal jumps in rise produce shrinking jumps in angle as the roof steepens. It is why a 4/12 and a 6/12 look quite different despite being only two numbers apart, while a 20/12 and a 22/12 look almost the same.

Converting a pitch to degrees yourself

The chart is built from one formula, so you can reproduce any value with a calculator that has an arctangent (often written tan-1 or atan) button.

The logic is pure right-triangle trigonometry. The rise and the run form the two legs of a right triangle, and the roof surface is the hypotenuse. The tangent of the roof angle equals the opposite side (rise) over the adjacent side (run), so taking the arctangent of rise-over-run returns the angle. Because the run is standardised to 12, you are always taking the arctangent of your pitch number divided by 12. The full method, including how to do it without a scientific calculator, is in how to calculate roof pitch in degrees.

Converting degrees back to a pitch

Going the other way, from a known angle to the x/12 pitch, uses the tangent function instead of its inverse.

This is how you handle the common questions “what pitch is 30 degrees” or “what pitch is 45 degrees”. A 30 degree roof is close to 7/12, and a 45 degree roof is exactly 12/12. Because roofs are framed to whole pitches, you normally round the result to the nearest standard pitch, then confirm it against the chart. If your angle sits exactly between two pitches, the choice usually comes down to which standard pitch the rest of the structure was designed around.

Why you would need the angle instead of the ratio

Most day-to-day roofing runs on the x/12 ratio, so it is fair to ask when the degree value actually matters. Three situations account for almost all of it. Solar panel planning is the biggest: panel tilt, shading, and energy yield are all modelled in degrees, so an installer needs the roof angle, not the pitch ratio. Our best roof pitch for solar panels guide leans on exactly these values.

The second is cutting and setting tools. A miter saw, a bevel gauge, or a rafter angle square is set in degrees, so when you cut a plumb or seat cut you need the angle. The third is documentation and international work: outside the United States, roof slope is often specified in degrees or as a percentage rather than in twelfths, so a plan from another country will give you an angle you must translate back. In each case, the chart above (or the calculator) is the bridge.

Pitch, angle, and percentage together

The slope percentage column deserves a word, because it is a third way of stating the same steepness and it confuses people who expect it to match the angle. Percentage slope is simply rise divided by run times 100, so a 6/12 pitch is a 50 percent slope, not a 50 degree angle. The percentage and the degree value only coincide at low slopes and then diverge sharply, which is why you should never treat a percentage as if it were degrees.

A 12/12 pitch makes the point cleanly: it is a 100 percent slope but only a 45 degree angle, because at 45 degrees the rise finally equals the run. Percentage slope shows up in drainage, road and site grading, and some European roofing specs. If you work across those fields, keep all three columns of the chart handy so you can move between them without error.

What each angle looks like on a real roof

Numbers on a chart are abstract, so it helps to anchor them to how a roof actually appears. Below roughly 18 degrees (under about 4/12) a roof reads as low and modern, and from the street it can look almost flat. Between 18 and 27 degrees (4/12 to 6/12) is the classic suburban look most people picture when they imagine a house. From 27 to 34 degrees (6/12 to 8/12) the roof starts to feel prominent and traditional, the kind of slope you see on older homes and steep-climate houses that shed snow well.

Past about 34 degrees (8/12 and up) the roof becomes a dominant feature of the building and stops being comfortably walkable. At 45 degrees (12/12) the two slopes are as steep as they are wide, the signature of A-frames and some Alpine and Gothic styles, explored in the A-frame and hip roof guide. Matching the angle to the look you want, and to the climate, is the subject of what roof pitch do I need.

Why the chart uses a base of 12

Every value in this chart depends on one convention: the run is fixed at 12 inches. That choice is not arbitrary. Twelve inches is one foot, the base unit of the customary building system, so expressing rise per foot of run made pitch easy to communicate on a job site long before calculators existed. A carpenter could say a roof was “eight in twelve” and everyone understood the rafter would climb eight inches for every foot it ran horizontally. The framing square, the original roofing tool, is built around this 12 inch base, with rise numbers on one arm and the fixed 12 on the other.

Because the base is always 12, the angle depends only on the rise, which is what lets a single chart cover every roof. If the industry had chosen a base of 10 or a metric base of 100, the ratios would look different but the underlying angles would be identical, since the angle is a property of the slope itself rather than of the units. When you see a European drawing that gives slope as a percentage or as degrees, it is describing the same physical steepness through a different base. Converting is just a matter of returning to rise over run and taking the arctangent, exactly as the degrees guide explains.

Converting without a scientific calculator

If you are on a roof with only a phone and no trig button in reach, there are two quick ways to get the angle. The simplest is to trust the chart above, which is why it exists, but if you have measured an odd pitch that is not listed you can interpolate. Between two chart rows the angle changes almost evenly for shallow pitches, so a pitch of 4.5/12 sits close to halfway between the 4/12 value of 18.43 degrees and the 5/12 value of 22.62 degrees, roughly 20.5 degrees. That estimate is well within the tolerance of most framing or estimating jobs.

The second method is to use the rise directly as a percentage and then look up the nearest angle. A rise of 5 in 12 is a 41.7 percent slope, and once you have the percentage the chart gives you the matching degree value. For anything requiring precision, open the roof pitch calculator, which carries the full decimal accuracy of the arctangent without any interpolation error. Save the mental methods for rough field checks and let the calculator handle the numbers you are going to cut or order against.

Turning the angle into saw cuts

One of the main reasons a builder converts pitch to degrees is to set a saw. When you frame a rafter you make two key angled cuts, and both come directly from the roof angle. The plumb cut, where the rafter meets the ridge, is vertical when the rafter is in place, so its angle off square equals the roof angle itself. For an 8/12 roof at 33.69 degrees you set your saw or mark your square to that angle for the plumb cut. The seat cut, or bird’s mouth, where the rafter sits on the wall plate, is the complement, so it uses 90 minus the roof angle.

This is why the degree column matters so much to anyone cutting their own rafters rather than buying trusses. Get the angle wrong and the rafter either will not seat flat on the wall or will not meet the ridge cleanly, and the error compounds across every rafter in the roof. If you are framing from scratch, pair this chart with the rafter length guide, which turns the same pitch into the length of the rafter and the position of the bird’s mouth, and the single-pitch roof guide for the simplest framing case.

Common conversion mistakes to avoid

A conversion chart removes most errors, but a few still slip through. Watch for these when you move between pitch, degrees, and percentage.

Sidestep those four and the chart will serve you reliably. When a converted value looks wrong against how the roof actually appears, re-measure the pitch first using the measuring guide, because a bad pitch reading is the usual root cause of a bad angle.

How the angle affects how a roof performs

The angle in the chart is not just a number for paperwork; it predicts how the roof will behave. Water and snow shed faster as the angle rises, which is why cold and wet climates favour steeper pitches and why a low-slope roof needs a sealed membrane rather than shingles. Somewhere around 18 degrees (a 4/12 pitch) is the point below which loose-laid materials start to struggle, and below about 9.5 degrees (2/12) you are into true low-slope territory with its own rules, covered in how to roof a low-pitch roof.

Wind works the opposite way. A steeper angle presents more face to the wind and catches more uplift, so very steep roofs need stronger fixings and cost more to build, while a shallow roof gives the wind less to push against but sheds water poorly. The angle therefore sits at the centre of a trade-off between weather shedding and wind resistance, which is why regional building traditions settled on the pitches they did. If you are choosing a pitch rather than measuring one, what roof pitch do I need and best roof pitch for snow weigh these factors, and why roof pitch matters ties them together.

Reading the angle on international and metric plans

The x/12 ratio is a North American habit. Much of the rest of the world specifies roof slope in degrees or as a percentage, and some older or European plans use a rise in millimetres over a metric run. This chart still works, because degrees are universal. If a drawing lists a 22 degree roof, that maps to a 5/12 pitch on the chart, and you can frame it in customary units without further conversion. If it gives a percentage, divide by 100, take the arctangent, and read the nearest pitch.

Metric roofing sometimes states the rise per metre of run rather than per foot. A rise of 250 mm per 1000 mm of run is a 25 percent slope, which the chart shows sits between a 3/12 and a 4/12 pitch at about 14 degrees. Whenever the units look unfamiliar, the safe move is to reduce everything to a plain rise over run ratio, then use the arctangent (or the calculator) to land on the degree value, and finally read across to the customary pitch you will actually build in.

Using the angle on quotes, permits, and inspections

When you request a roofing quote, provide the pitch as both the ratio and the angle if you can, because different trades default to different systems and giving both removes ambiguity. A solar installer will want the degree value, a framer will want the x/12, and an inspector may want to see that your chosen material is rated for that slope. Stating “6/12, which is 26.57 degrees” in one line saves a phone call and prevents a mismatch between what you ordered and what gets built.

On the compliance side, the angle or its equivalent pitch determines which materials pass. Codes and manufacturers set minimum slopes, and the reviewer will check your roof against them, so knowing the exact figure from this chart lets you confirm compliance before you submit rather than after a rejection. The material-by-material thresholds are collected in what is the minimum roof pitch, with dedicated guides for shingles and metal.

How this chart was calculated

For transparency, every angle here comes from a single computation: the arctangent of the pitch number divided by 12, converted from radians to degrees. So the 7/12 row is arctan of 7 over 12, which is arctan of 0.5833, equal to 30.26 degrees, and the slope percentage is 7 over 12 times 100, which is 58.3 percent. There is no rounding in the method itself, only in the two-decimal display, so if you need more precision the calculator will carry additional decimals.

That consistency is the reason a chart like this can be trusted across every trade. The relationship between rise, run, and angle is fixed by geometry and does not change with fashion, climate, or country. Measure the pitch correctly, and the angle follows with certainty. If you ever doubt a value, reproduce it with the arctangent formula above and you will land on the same number the chart gives, which is exactly what makes it a reliable reference to keep on hand.

The two ends of the chart: very low and very steep

The middle of the chart, roughly 4/12 to 9/12, covers the vast majority of houses, but the extremes are where the angle really changes how a roof is built and used. At the low end, a 1/12 pitch is only 4.76 degrees and a 2/12 is 9.46 degrees. Those angles are so shallow that water moves slowly and wind-driven rain can creep back up under overlapping materials, which is why shingles are usually not permitted below about 2/12 and why these roofs lean on membranes and sealed seams instead. If your reading lands down here, treat the roof as low-slope and read how to roof a low-pitch roof and the minimum pitch guide before choosing a covering.

At the high end, angles climb steeply in feel even though the pitch numbers keep marching up by one. A 12/12 is 45 degrees, a 16/12 is 53.13 degrees, and a 24/12 is 63.43 degrees, well past the point where anyone walks the roof unaided. These very steep angles belong to A-frames, spires, turrets, and dramatic architectural roofs, and they carry heavy wind loads and demanding access requirements. The practical ceiling for an ordinary house is around 12/12, and anything above it is a design statement that needs engineered fixings and professional installation, as the steep roof pitch guide explains. Knowing exactly where your angle sits on this spectrum tells you immediately whether you are dealing with a routine roof or a special case.

What to do when your angle falls between two pitches

Real measurements do not always land on a clean whole-number pitch. You might read an angle of 24 degrees, which sits between the 5/12 value of 22.62 degrees and the 6/12 value of 26.57 degrees. In new construction the answer is simple: pick the nearest standard pitch and build to it, because framing lumber, trusses, and flashing are all made for whole pitches and a fractional pitch only complicates every cut. Twenty-four degrees rounds to a 5/12, so you would frame a 5/12 and move on.

On an existing roof, a between-pitch reading usually means one of three things: the roof really was built to a half pitch such as 5.5/12, your measurement picked up a sag or an uneven course, or you measured across a transition between two planes. Re-measure on a clean, straight section of a single plane, and if the odd angle persists, record the exact value from the calculator for material ordering, since the surface area still depends on the true angle even if you describe the roof by its nearest standard pitch. When precision matters, as it does for solar tilt or a custom flashing bend, use the measured angle rather than the rounded pitch.

Typical roof angles by building type

It helps to connect the abstract degree values to the buildings you see every day, because the angle is often the quickest way to recognise what a structure is. Modern and contemporary homes frequently sit at 2/12 to 4/12, roughly 9 to 18 degrees, giving that clean low-profile look. The traditional American house lands squarely in the 4/12 to 8/12 band, about 18 to 34 degrees, which balances weather shedding, attic space, and cost. Ranch and mid-century homes tend toward the shallow side of that range, while colonial and older houses climb toward the steep side.

Purpose-built and regional roofs push the extremes. Barns and Gothic revival houses reach 12/12 and beyond, past 45 degrees, to shed snow and create lofty interiors. Alpine and chalet roofs use steep angles for the same snow-shedding reason, while sheds, porches, and lean-tos often sit at a shallow 2/12 to 4/12 because they only need to move water off a small area, a case covered in the shed pitch guide and the lean-to guide. Solar-optimised roofs are increasingly built near the local latitude angle, often 25 to 35 degrees, to maximise panel yield.

These band ranges are guides rather than rules, and plenty of houses blend styles or carry more than one pitch, but they give you a fast mental map. When you spot a low, sweeping roof you can reasonably guess it sits under 18 degrees, and when you see a tall, dramatic one you can guess it is past 34, then confirm the exact figure by measuring and checking this chart. That habit of estimating first and verifying second is how experienced roofers read a building before they ever set a ladder against it.

Reading the angle off this chart, then, does more than fill in a form. It places a roof in context, tells you what materials and access methods suit it, and hints at the climate and era it was built for. When you next look up a pitch, glance at the category and use-case columns too, because together they turn a single number into a full picture of the roof in front of you. And whenever you need to move between the pitch, the angle, and the percentage in the other direction, the roof pitch calculator and this chart will always agree.

Skip the chart with the calculator

A printed chart is handy on a job site, but when you need an exact figure or a value between the whole pitches, the roof pitch calculator is faster and more precise. Enter the pitch and it returns the angle to as many decimals as you need, plus the percentage and the rafter multiplier, so you can move straight into estimating. It also converts an angle back to a pitch if that is the direction you need.

From the angle you can flow into the connected tools: use roof area with pitch to size a material order, or the rafter length guide to cut framing at the right angle. The roof pitch tool sits with the other estimators in the construction calculators category, and you can browse the whole roofing library in the roof pitch blog or find site-work tools like the dirt calculator on the homepage. However you get there, the chart and the calculator agree, because they are built from the same arctangent relationship.

Roof pitch angle chart: frequently asked questions