Roof Slope Ratio Calculator

The rise is the height of the roof and the run is the horizontal span as pictured above.

Roof slope ratio calculator.

It is often compared to slope but is not exactly the same. The pitch is commonly defined as the ratio of rise over run in the form of x 12. For example if you measure 4 inches the pitch of your roof is 4 12. Roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

For example if a roof has a pitch of 4 12 then for every 12 inches the building extends horizontally it rises 4 inches. The roof pitch is the slope of the rafter. A ratio of 1 1 62 is known as the golden ratio and therefore the vast majority of roof pitch in degrees charts you see will be working to this ratio at the very least. First convert the pitch to a slope.

With a 12 in 12 slope the wall or roof rises 12 inches in a 12 inch run a 12 in 12 slope 45 one could be inclined to assume that a 6 in 12 slope would equal half of that 22 5. Slope tilt or inclination can be expressed in three ways. Rise run rise run slope. 1 as a ratio of the rise to the run for example 1 in 20 2 as an angle almost always in degrees 3 as a percentage called the grade which is the rise run 100.

To do this simply convert the rise and run as a fraction to a decimal form eg. This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares. This will give you the rise over run or pitch. This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof.

Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter. Roof pitch calculator results explained slope the slope of a roof is represented as x 12 where x is the number of inches in rise for every 12 inches of run. A 4 12 is a roof slope that rises by 4 inches for every 12 inches across. To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.

In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches.