Roof pitch can be written as an x:12 ratio, an angle in degrees, or a percentage slope. A practical roof pitch calculator app should connect those formats and let you begin with the measurements already available—whether that is a rise and horizontal run, a known pitch, or one missing side of the roof triangle.
Construction Calculator is included in Unit Converter, with dedicated Pitch, Rise, Run, and Rafter tools that keep the inputs and related results together. For anyone looking for a free roof pitch calculator app, Unit Converter is free to download for Android, iPhone, and iPad.
What do rise, run, pitch, and angle mean?
A simple roof slope forms a right triangle. The run is the horizontal distance. The rise is the vertical height gained over that run. The sloping side connects those two measurements, while the angle is measured above the horizontal run.
Roof pitch is commonly normalized to 12 units of horizontal run. A 6:12 pitch means the roof rises 6 units for every 12 units it travels horizontally. The same relationship can also be expressed as a 26.57-degree angle or a 50% slope.
How to calculate roof pitch with rise and run
To calculate an x:12 pitch manually, divide the rise by the run and multiply by 12:
Pitch = (rise ÷ run) × 12
For a roof with a 6 ft rise and a 12 ft horizontal run, the calculation is (6 ÷ 12) × 12 = 6. The roof pitch is therefore 6:12.
In the app, the same calculation takes four short steps:
- Open Construction Calculator and select Pitch.
- Enter the vertical Rise as 6 ft.
- Enter the horizontal Run as 12 ft.
- Read the 6:12 result, then use Next to review the related values.
The result pages keep the same roof geometry in view: 6:12 pitch, 26.57-degree angle, 13 ft 5 in rafter line length, and 50% slope. You can move through them without entering the rise and run again.
Watch the roof pitch calculation
See how a 6 ft rise and 12 ft run produce a 6:12 pitch, then move through the connected angle, rafter-length, and percent-slope results.
Use a roof pitch to degrees calculator
A pitch ratio and an angle describe the same slope in different forms. To calculate the angle manually, use the arctangent of rise divided by run:
Angle = arctan(rise ÷ run)
For the 6 ft rise and 12 ft run example, arctan(6 ÷ 12) gives 26.57 degrees. Construction Calculator shows this on the next result page after the 6:12 pitch, making it easy to move from the ratio on a plan to the corresponding angle.
See the same slope as a percentage
Percent slope compares the rise directly with the horizontal run:
Percent slope = (rise ÷ run) × 100
A 6 ft rise over a 12 ft run is 50%. This does not describe a different roof; it is another way of expressing the same 6:12 pitch and 26.57-degree angle. The Pitch tool groups these related answers so you can use the format that matches the drawing, discussion, or calculation in front of you.
Roof rise calculator: start with pitch and run
Sometimes the pitch and horizontal run are known, but the vertical rise is not. Select Rise, enter the run, and enter the pitch number; the field supplies the :12 part. With a 12 ft run and a 6:12 pitch, the result is a 6 ft rise.
The following pages provide the connected values for that triangle, including its diagonal line length, angle, and percent slope. This is useful when a drawing gives the pitch ratio and horizontal dimensions but you also want to understand the resulting vertical rise.
Roof run calculator: start with rise and pitch
When the rise and pitch are known, select Run. Enter a 6 ft rise and a pitch value of 6, and the calculated horizontal run is 12 ft. As with the other roof tools, Next moves through the related geometry without rebuilding the inputs.
Having separate Pitch, Rise, and Run tools keeps each workflow direct: choose the value you want to find, then enter the two values you already know.
Enter roof measurements in familiar units
The roof tools accept feet and fractional inches, decimal inches, meters, and centimeters. This allows a rise or run to remain in the format used by the tape, drawing, or specification. Supported units can be mixed across input lines, and compatible result-unit buttons change how a displayed length is presented.
If roof measurements include fractional inches, the same Construction Calculator also provides direct FT/IN entry. Our feet and inches calculator app guide shows how to enter, add, multiply, and convert those tape-measure values.
Who can use these roof tools?
Roofers and framers can translate field dimensions into a familiar x:12 pitch and angle. Estimators can compare the related triangle values while preparing project measurements. Builders, remodelers, inspectors, designers, and DIY users can use the same workflow for house roofs, additions, sheds, porches, and other sloped structures.
Because Construction Calculator sits inside Unit Converter, the same app also brings together broader measurement conversions and focused tools for stairs, baluster and stud layouts, lumber, miters, areas, volumes, weights, and common shapes.
What makes a useful mobile roof pitch calculator?
- A clear starting point: Choose Pitch, Rise, or Run according to the missing value.
- Familiar measurement entry: Work with feet, inches, fractions, decimal inches, meters, or centimeters.
- Connected results: Review pitch, angle, percent slope, and the diagonal roof-triangle length from the same inputs.
- Readable x:12 pitch: Keep the result in the notation commonly used on roof plans and in building discussions.
- Related project tools: Continue into dimensional calculations, layout, lumber, and other construction workflows when needed.
Frequently asked questions
Can the app calculate roof pitch from rise and run?
Yes. Select Pitch, enter the rise and horizontal run, and the app returns the normalized x:12 pitch. Press Next to review the angle, rafter line length, and percent slope.
Can it convert a roof pitch to degrees?
Yes. The Pitch result pages include the corresponding angle in degrees. A 6:12 pitch is shown as 26.57 degrees.
Can it calculate a missing rise or run?
Yes. Use Rise when the run and pitch are known, or use Run when the rise and pitch are known.
Does it support metric roof measurements?
Yes. Documented input units include meters and centimeters as well as feet, fractional inches, and decimal inches.
Is Roof Pitch Calculator a separate download?
No separate download is needed. The roof tools are included inside Unit Converter, which is available from Google Play and the App Store.
Calculate the roof value you need
Start with rise and run to find pitch, begin with pitch and run to find rise, or combine pitch and rise to find the horizontal run. For a wider look at the app’s building and layout tools, see our Construction Calculator app guide.
Download Unit Converter on the App Store for iPhone or iPad, or get Unit Converter on Google Play for Android.