Roof Slope Calculator

Step-by-Step Guide to Using the Roof Slope Calculator

This guide will walk you through using the Roof Slope Calculator to determine various aspects of your roof’s geometry, including the slope angle, slope ratio, roof length, and roof area. Follow these simple steps to make your calculations.

Step 1: Enter the Run Length

Begin by entering the Run Length, which is the horizontal distance in feet. This value must be between 0.1 and 1000 feet. Use a decimal if precise measurements are necessary. This input is required for the calculator to function, so ensure it’s filled out accurately.

Step 2: Enter the Rise

Next, input the Rise, the vertical height in feet. Similar to the run length, this value must be between 0.1 and 100 feet and is also mandatory. Use this measurement to reflect the actual height increase across the run of your roof.

Step 3: Enter the Roof Width

The third required field is the Roof Width, which should also be given in feet. This measurement should be between 0.1 and 1000 feet. As with the others, it is a compulsory field and ensures that the calculations for roof surface area are precise.

Step 4: Review the Calculated Results

Once you’ve entered all the necessary values, the calculator will provide several calculated outputs:

• Roof Slope Angle: This is calculated using the formula atan(rise/runLength) * (180/pi) and will display the angle in degrees. The result will appear with one decimal precision, followed by the degree symbol.
• Slope Ratio: The formula used here is rise * 12/runLength, presenting the slope as a ratio of vertical inches per horizontal foot. The format will display a precision of one decimal and in the form of 1:x (inches per foot).
• Actual Roof Length: Determined by the formula sqrt(pow(runLength, 2) + pow(rise, 2)), this value represents the actual length of the roof surface considering the slope. The result is shown with two decimal places, expressed in feet.
• Roof Surface Area: Calculated using sqrt(pow(runLength, 2) + pow(rise, 2)) * roofWidth, this value gives you the total surface area of the roof in square feet. The result is displayed with two decimal precision.

Once all required values are properly entered, these calculated results provide a comprehensive analysis of your roof’s slope and dimensions. Use these results for construction planning, comparison, and adjustments as necessary for your roofing project.