Our roof pitch calculator is a useful tool for determining the pitch of your home roof and the length of rafters you’ll need for your building project. We’ll walk you through the procedure of determining the roof pitch step by step. This roof pitch calculator may also convert roof pitches from degrees to percent.

What is the roof pitch?

The slope generated by the rafter is known as roof pitch. We can measure it in two ways: as the angle formed by the rafter with the horizontal, or as the ratio of the rise to the run of the roof.

In the form of x:12, we commonly state the roof pitch as a ratio between rising and run. For instance, a pitch of 1:12 indicates that the rise will be equivalent to one yard for every twelve yards of building length.

Roofs can be classified into the following categories:

In practice, flat roofs do not need to be absolutely level to allow water drainage. The pitch of these roofs ranges from 1/2:12 to 2:12. (from 4.2 percent to 16.7 percent ).

Roofs with a pitch of less than 4:12, we consider low pitched (33.3 percent). These are typically difficult to maintain since they need particular materials to prevent leakage.

Roof pitches on traditional roofs range from 4:12 to 9:12. (33.3 percent to 75 percent). As a result, they’re the simplest to build, and they’re also the safest to walk on.

Additional fasteners are frequently required on high-pitched roofs. They can reach a slope of 21:12 if necessary (175 percent).

How to calculate roof pitch?

We usually estimate Roof pitch using the same method used to define a right triangle. To get the length of the rafter and the slope, apply the following equations:

  • The Pythagorean Theorem says that rafter^2 = rise^2 + run^2
  • Rise / run = pitch, where we express the pitch in percent; and
  • Pitch = tan (angle), where we express the angle of the roof pitch in degrees.

Calculate the pitch and insert 12 for the run length to get the roof pitch in the form of x:12. Your x will indicate the value as the increase.

Roof pitch chart

A roof pitch chart is just a basic guide that offers a roofing firm to assist you in discovering what the normal roof pitches are. They usually offer you in the form of a roof pitch diagram chart, but they can also present to you in the form of a conversion format.

Roof pitch conversion charts are quite beneficial for one thing: they offer you all of the information you’ll need to provide specialists.

They can work to your requirements if you provide them with the detailed chart and measurement you desire. The charts are intended to give customers a sense of what the real slope on the roof would look like, and for many individuals, the steeper looks are preferred.

This is because steeper designs tend to suit the “Golden Ratio,” which all architects adhere to. The “Golden Ratio” is a ratio of 1:1:62, and the great majority of roof pitch in degrees charts you encounter will be operating with this ratio at the very least.

Rood pitch angles

Roof PitchAngleRoof Pitch Multiplier

6 12 roof pitch

The first figure refers to how many inches the roof rises every 12 inches when it comes to roof pitches.

For instance, a 6/12 roof has a 26.57-degree angle.

When discussing the steepness of a roof, keep this in mind. For example, the slope of a 3/12 pitch roof is substantially lower than that of an 8/12 pitch roof.

A 6/12 roof pitch indicates 12 inches of run, or span, for every 6 inches of elevation. A 6/12 pitch has a 22.5-degree angle, whereas a 12/12 pitch has a 45-degree angle.

Roof pitch factor

The roof pitch conversion factor is a statistic that gives an approximation of the sloping roof’s total surface area when multiplied by the roof’s size. We also know it as the roof pitch multiplier.

The roof pitch multiplier formula is derived from the right triangle formula, especially the Pythagorean Theorem:


Roof pitch calculator – example of use measure

  • Measure the run length – it is the horizontal distance between the roof ridge and the wall of the building. Let’s assume it is equal to 7 m.
  • Measure the rise of your roof. Let’s say it is equal to 2 m.
  • Calculate the rafter length, substituting these values into the following formula:
rafter² = rise² + run² = 2² + 7² = 4 + 49 = 53.00\newline rafter = √53 = 7.28 m
  • Calculate the roof pitch as the proportion of rise and run:
pitch = rise / run = 2 / 7 = 28.57%
  • Recalculate this value into an angle:
angle = arctan(pitch) = arctan(0.2857) = 15.95°
  • Finally, you can find the roof pitch in the form of x:12.
x = pitch * 12 = 0.2857 * 12 = 3.4289
  • The pitch of your roof is 3.5:12. We can also write it down as 28.57% or 15.95°.

Frequently Asked Questions

What is the standard pitch for a roof?

Roof pitch is a ratio that represents the slope of a roof. Although no one standard roof slope is utilized on all sloping roofs, factors such as roofing materials and local climate assist in determining the acceptable range of pitches for a certain structure. Roof pitches that are most typically utilized range from 4/12 to 9/12.

What is the average quote for getting a roof pitched?

Because of the variety of design options and materials available, working with an average price per square meter is sometimes easier. For example, it cost $ 33.51 per square meter for a shallow pitched roof.

What is the minimum roof pitch for snow?

Roofs in snowy areas should have a minimum slope of 10 degrees. Snow melts faster on a steeply sloped roof.
While the angle of the roof aids in snow shedding, adding too many angles to the roof for a more aesthetic impact may pose structural issues with snow shedding in the winter. Complex designs hamper the capacity of the roof to shed snow with numerous curves and corners. Snow tends to become clogged at every angle it meets. Make sure that water and heavy snow can readily escape from your roof.

What is a 4/12 roof pitch?

A “4 in 12” slope is defined as a roof that rises 4 inches for every 1 foot or 12 inches of run. The slope ratio denotes how much vertical increase is for every 12 inches of horizontal run. A “4 in 12” slope, for example, can be stated as a ratio of 4:12. The ratio of a “6 in 12” slope is 6:12.

What is the best pitch for a roof?

Roof slope is a ratio that represents the slope of a roof. Although no one standard roof angle is utilized on all sloping roofs, factors such as roofing materials and local climate assist in determining the acceptable range of pitches for a certain structure. Roof pitches that are most typically utilized range from 4/12 to 9/12.

What is the smallest pitch of a roof?

A roof’s lowest pitch is 1/4:12, which translates as a 1/4 inch rise to a 12-inch run. With built-up or specialist synthetic roofing, such a narrow pitch can only be achieved.

What roof pitch is 30 degrees?

A 30° roof pitch is equivalent to a 7/12 roof pitch. To convert from degrees to the American ratio, use the following formula: Find the angle’s tangent, tan (angle). This provides you with the roof pitch.

What is a roof pitch multiplier?

A roof pitch multiplier, also known as a roof pitch factor, is a statistic used to calculate the true surface area of a pitched roof. To calculate the actual surface area of a sloping roof, multiply the roof pitch multiplier by the area, or footprint, covered by the roof.

What roof pitch is walkable?

What is the maximum walkable roof pitch? Roof pitches of 6/12 (26.5°) or less are deemed easily walkable and do not need additional precautions. A pitch of 7/12 (30°) is doable, although care should be exercised.

What is the minimum pitch for a corrugated metal roof?

Corrugated roofing is an excellent choice for typical pitched roofs, but it has serious limits when the pitch falls below 5 degrees. As a result, all roofing manufacturers recommend a 5-degree pitch as the minimum slope, and they will not issue any warranties if it is built any lower.