Pitched Roof Angle Calculator

If you’re building a roof or planning a shed, you’ll need to know the roof pitch. But let’s be honest calculating angles can feel like a school math test. That’s where our Pitched Roof Angle Calculator comes in. It takes your roof's rise and run and instantly shows you the angle, slope, and pitch format.

What Is Roof Pitch?

Roof pitch tells you how steep a roof is. It’s measured as an angle (in degrees), a slope (like 3-in-12), or a percentage. For example, a 3/12 roof means the roof rises 3 inches for every 12 inches it runs horizontally.

How to Calculate Roof Pitch Angle

You don’t need to be a math wizard. You just need two numbers:

• Rise – how much the roof goes up
• Run – how far the roof goes across

Then use this simple formula:

Angle (θ) = arctangent(rise ÷ run) × 180 ÷ π

That’s it! This gives you the roof angle in degrees.

Example:

If your rise is 1.5 meters and run is 6 meters:

θ = arctan(1.5 / 6) × 180 ÷ π  

θ = arctan(0.25) × 57.2958  

θ ≈ 14.04°

You also get:

• Slope (%) = (rise ÷ run) × 100
• Pitch = (rise ÷ run) × 12 (as in 3-in-12, 4-in-12 etc.)

How to Use the Pitched Roof Calculator

Using our tool is super simple:

1. Enter your roof rise and run.
2. Choose your units (meters, feet, inches, etc.).
3. Click Calculate.
4. Boom! You’ll get:
   - Angle in degrees and radians
   - Slope as percent and decimal
   - Rise-in-12 pitch
   - Easy description (low, medium, high pitch)

What’s the Golden Rule for Roof Pitch?

The golden rule? Safety and drainage. Most roofs should have at least a 10° pitch to allow water to run off. In snowy areas, a steeper roof helps snow slide off, reducing weight and risk.

What Degree Is a 3/12 Pitch Roof?

Great question. Let’s solve it.

Slope = 3 ÷ 12 = 0.25  

Angle = arctan(0.25) × 180 ÷ π ≈ 14.04°

So, a 3/12 pitch is about 14 degrees.

What Angle Do You Cut for a 6/12 Roof Pitch?

Let’s do the math.

Slope = 6 ÷ 12 = 0.5  

Angle = arctan(0.5) × 180 ÷ π ≈ 26.57°

So, you’d cut your rafter ends at about 26.6 degrees.

Final Verdict

Whether you’re a builder, homeowner, or DIY fan, knowing your roof angle saves time, materials, and mistakes. Our pitched roof angle calculator makes it fast, easy, and accurate. No math headaches. No guessing.

Just type, click, and build.

FAQs

Can I use this calculator for any unit?

Yes! It supports meters, feet, inches, centimeters, and millimeters.

What’s a good roof pitch for heavy rain?

Go for at least 25–30° to help water drain fast.

Is flat roof really flat?

Not quite. Even flat roofs have a slight pitch (1–3°) to drain water.

What’s a high pitch roof?

Anything above 25° is usually considered steep or high pitch.