# Free Roof Pitch Calculator

## Find the rafter length required for a building roof with this free roof rafter calculator.

##### Roof inputs
Run length
Enter a number greater than 0
Roof Rise
Enter a number greater than 0

Rafter length m
Roof pitch o
Roof pitch %

## What is the roof pitch?

Roof pitch, also known as roof slope or roof angle, is a crucial architectural term that refers to the steepness of a roof. It measures the incline of the roof surface in relation to the horizontal plane. This slope is typically expressed as a ratio of vertical rise to horizontal run.
The pitch of a roof plays a significant role in determining its design, aesthetics, and functionality. Steeper pitches shed water, snow, and debris more effectively, making them suitable for regions with heavy precipitation. On the other hand, roofs with shallower pitches are more common in areas with milder weather conditions.
Roof pitch is often represented in two ways:
• Angle in degrees: It indicates the angle at which the roof slopes up from the horizontal plane. For instance, a 30-degree pitch means the roof rises 30 degrees from the horizontal.
• Ratio: The ratio is expressed as the number of units of vertical rise for every 12 units of horizontal run. For example, a 6:12 pitch implies the roof rises 6 units vertically for every 12 units horizontally.

## How to calculate roof pitch?

Roof pitch is most commonly expressed as a fraction or as a percentage using the following method
Roof Pitch as a Fraction
The roof pitch in fraction format represents the vertical rise in inches for every 12 inches of horizontal run. To calculate it, follow these steps:
1. Measure the vertical rise: Measure the distance from the top of the roof (ridge) to the bottom (eaves) along a vertical line. This is the vertical rise.
2. Measure the horizontal run: Measure the distance from the outer edge of the eaves to the house's outer wall. This is the horizontal run, which is typically 12 inches (since it's measured in feet).
3. Write the pitch as a fraction: Divide the vertical rise by the horizontal run and express it as a ratio. For example, if the vertical rise is 6 inches, then the pitch is 6/12. You can simplify this fraction, if possible (in this case, it simplifies to 1/2).
Roof Pitch as an Angle:
Roof pitch can also be represented in degrees. To calculate it, you can use trigonometry with the rise and run measurements:
• Measure the vertical rise: Same as in the fraction method, measure the vertical distance from the ridge to the eaves.
• Measure the horizontal run: Same as in the fraction method, measure the horizontal distance from the eaves to the house's outer wall.
• Use trigonometry to calculate the angle: Divide the vertical rise by the horizontal run, and then take the arctangent (inverse tangent) of this ratio to find the angle in degrees. Most calculators have an "arctan" or "tan^-1" function that you can use for this purpose.

## What is the standard pitch for a roof?

The standard pitch for a roof typically refers to the slope or angle of the roof, and it is often expressed as a ratio of vertical rise to horizontal run. This pitch is commonly used in construction and roofing to determine the design and materials needed for the roof.
The pitch is represented as "X:12," where X is the vertical rise (in inches) for every 12 inches of horizontal run. For example, a 4:12 pitch means the roof rises 4 inches vertically for every 12 inches horizontally.
The most common standard pitches for residential roofs are:
• 4:12 pitch - A moderate slope often found on many residential homes.
• 6:12 pitch - Slightly steeper than 4:12 and offers better drainage in areas with heavy rainfall or snow.
• 8:12 pitch - A relatively steep slope used for areas with heavy snowfall or to achieve a more distinctive architectural style.

## What is the minimum roof pitch for snow?

The minimum roof pitch for shedding snow is around 30Β°, or a 6:12 or 7:12 slope, however this should be assessed by a professional on a case by case basis.

## What is a 4/12 roof pitch?

A 4/12 roof pitc is a common residential roof pitch. The 4 represents the vertical rise of the roof and the 12 represents the horizontal run.

## What is the best pitch for a roof?

The best pitch for a roof depends on several factors, including the climate in the area, the type of roofing material used, local building codes, and personal preferences. The pitch of a roof refers to the slope or angle of the roof's surface.
Here are some common roof pitches and their advantages:
• Low-Pitch Roof (2:12 to 4:12): This type of roof has a slight slope, and it is easier and more affordable to construct. However, it may not be as effective in shedding water and snow, so proper waterproofing and drainage solutions are crucial.
• Moderate-Pitch Roof (4:12 to 6:12): This pitch strikes a balance between aesthetics and practicality. It offers better water and snow shedding capabilities than a low-pitch roof, while still being relatively straightforward to construct.
• Steep-Pitch Roof (6:12 and higher): This pitch provides excellent water and snow shedding capabilities. It's often used in areas with heavy rainfall or snowfall, as it prevents water and snow from accumulating on the roof. However, steep-pitch roofs can be more expensive to build due to the increased materials and labor required.

## What is the smallest pitch of a roof?

The smallest pitch of a roof is typically determined by the type of roofing material being used and local building codes. The pitch of a roof refers to the slope or angle of the roof surface, and it is usually expressed as a ratio of the vertical rise to the horizontal run. For example, a pitch of 1:12 means the roof rises 1 unit vertically for every 12 units of horizontal distance.
In general, the smallest pitch for most roofing materials is around 1:12, which means the roof is almost flat. Roofs with pitches lower than 1:12 are considered flat roofs. However, flat roofs may require special considerations, such as proper drainage systems, to prevent water from pooling and causing damage.
##### What's this calculator used for?
This free roof rafter calculator helps calculate the pitch of a roof, the rafter length required for a given roof rise, roof pitch angle and run length.
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