How To Calculate A Pitch Of A Roof​?

Measuring roof pitch can seem complicated, but it is very easy. You don’t need to be a professional roofer or a math expert to calculate it. To make the calculations easy for you, we’ve shared this step-by-step guide on how to calculate a pitch of a roof, and explain every step from measuring rise and run to converting pitch into degrees and using easy roof pitch charts.

Tools You’ll Need to Calculate a Roof Pitch

To start figuring out roof pitch, you’ll need:

• A tape measure (for rise and run).
• A level (at least 12 inches long).
• A pencil and a notepad to note measurements.
• A roof pitch chart (optional but helpful).
• Access an online roof pitch calculator (if you want an easy shortcut).

How To Calculate A Pitch Of A Roof​?

The pitch of a roof tells you how steep the roof is. It’s usually shown as a ratio of “rise” over “run.”

• Rise = the vertical height of the roof.
• Run = how far the roof goes across (horizontal distance).

Step 1: Measure the Run

• Place the level horizontally on the roof, sticking out at least 12 inches.
• Make sure the bubble in the level is centred (that’s how you know it’s perfectly flat).
• Mark the spot on the level exactly at 12 inches; this is your run.
• Always use 12 inches for easy measurement.

Step 2: Measure the Rise

• From the 12-inch mark on the level, measure straight up to the roof surface.
• The distance between the level and the roof is your rise.
• For example, if the rise measures 6 inches at 12 inches of run, your pitch is 6:12.

Step 3: Write It Down as a Ratio

Always write the roof pitch as “rise over run”,  for example: 6:12.

Common roof pitch ratios you might see:

• 4:12 (low slope)
• 6:12 (medium slope)
• 9:12 (steeper roof)

Step 4: Converting Roof Pitch into Degrees

Sometimes, especially for building plans, you need the roof pitch in degrees. Here’s how you can calculate it:

• Divide the rise by the run.
• Use a scientific calculator or an online calculator to find the angle.

Here’s the formula: Angle = arctangent (rise ÷ run)

Example: For a 6:12 pitch:

6 ÷ 12 = 0.5

Arctangent(0.5) = about 26.57 degrees

Step 5: Roof Pitch Charts

If you want to skip the math completely, a roof pitch chart makes it super easy. Just match your rise and run to the degrees in this table below:

So, if you measure a 6:12 pitch, simply check the chart: your roof has approximately 26.5 degrees of slope.

Use Online Roof Pitch Calculators

If you hate calculations, an online roof pitch calculator is a great tool. Here’s how it works:

1. Just type “online roof pitch calculator” into Google, and you’ll find a lot of calculators.
2. Enter your rise and run into the calculator.
3. Click calculate.
4. It gives you the pitch ratio and degrees.

Many online calculators even allow you to upload photos of your roof for easy measuring.

Some popular free calculators you can find are:

• Roofcalc.org
• Calculator.net
• Omni Calculator (Roof Pitch)

Conclusion

Learning the calculation for roof pitch sounds technical, but once you understand the basics, such as rise, run, and a few simple steps, you can confidently measure any roof like a pro. You can do the calculation for roof pitch by using different online calculators. And remember, if you ever get stuck, you can hire our expert roofers in Brighton who are ready to help you.

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