Roof pitch is the angle of your roof, measured as the number of inches it rises for every 12 inches it runs horizontally

A roof with a 6:12 pitch rises 6 inches for every 12 inches of horizontal distance. A 12:12 pitch (also called a 45-degree angle) rises 12 inches per 12 inches — that is a steep roof. A 2:12 pitch is nearly flat. Knowing your roof pitch matters because it affects how much material you need, what kind of shingles work on your roof, how water drains, and whether certain repairs or replacements are possible.

You can find your roof pitch in three ways: look at your home's blueprints or building permit, measure it yourself with basic tools, or hire a roofer to measure it for you. The DIY method takes about 15 minutes and requires only a level, a tape measure, and a pencil.

Key Takeaways

  • Roof pitch is written as a ratio like 6:12, meaning 6 inches of rise per 12 inches of horizontal run.
  • You can find your pitch on your home's blueprints, in your building permit documents, or by measuring it yourself with a level and tape measure.
  • The measurement must be taken on the actual roof or from inside the attic — you cannot calculate pitch from ground level.
  • Steeper pitches (8:12 and above) shed water faster but are harder to work on; shallow pitches (under 4:12) are easier to access but require special materials.

Check your home's existing documents first

The fastest way to find your roof pitch is to look at paperwork you may already have. Your original home blueprints, building permit, or inspection report often lists the pitch. If you bought the home recently, the inspection report may include it. If you are renting, your landlord or property manager may have the original plans.

Call your local building department and ask for your home's permit file. They keep these records and can tell you the pitch listed when the roof was built or last replaced. You will need your address and possibly your parcel number, which you can find on your property tax bill or county assessor's website.

Measure pitch from the attic using a level and tape measure

If you have attic access, this is the safest method. You do not have to climb onto the roof itself. Find a rafter — the wooden beam that runs from the peak down to the wall. Place a level on top of the rafter so it is perfectly horizontal. Measure straight down from the level to the rafter itself. That vertical distance is your rise. Then measure 12 inches horizontally along the level. The rise you measured becomes the first number in your pitch ratio, and 12 is always the second number.

For example: if your vertical measurement is 5 inches, your pitch is 5:12. If it is 8 inches, your pitch is 8:12. Write down the measurement clearly — you will use it to understand what materials and repairs your roof can handle.

Measure pitch from the roof surface using a speed square

A speed square (also called a rafter square) is a triangular tool sold at any hardware store for $10 to $20. It has a built-in angle scale that reads pitch directly. You place it on the roof surface so the blade sits flat against the shingles, and the angle scale shows you the pitch when ready. This method is faster than the level method but requires you to be on the roof.

If you use a speed square, wear shoes with good grip, work on a dry day, and consider using a safety harness if your roof is steep or high. If you are uncomfortable on a roof, do not attempt this — hire a roofer instead. A roofer can measure and tell you the pitch in minutes for a service call fee, usually $75 to $150.

Understand what your pitch number means for repairs and materials

Pitch affects what you can do with your roof. Roofs under 2:12 are considered flat and require special membrane materials (like EPDM rubber or TPO) rather than shingles. Pitches between 2:12 and 4:12 are low-slope and need underlayment and ice-and-water shield to prevent leaks. Pitches 4:12 and above can use standard asphalt shingles.

Steeper roofs (8:12 and above) shed water and snow faster, which is why they are common in snowy climates. They are harder to work on and more dangerous to access, so labor costs for repairs are higher. Shallow roofs are easier to walk on and cheaper to repair, but they are more prone to standing water and ice dams in winter. When you get a repair estimate or plan a replacement, tell the roofer your pitch — it determines whether the job is even possible and what it will cost.

Convert pitch to degrees if you need to compare it to other measurements

Sometimes you will see roof pitch written as a degree angle instead of a ratio. A 6:12 pitch equals roughly 26.6 degrees. A 12:12 pitch equals 45 degrees. If you need to convert your measured pitch to degrees, use this formula: divide the rise by 12, then use a calculator to find the arctangent (often labeled "tan⁻¹" or "atan"), then multiply by 57.3 to convert radians to degrees.

For most homeowners, the ratio form (like 6:12) is more useful because it is what roofers use and what you will see on material specifications. Degrees matter mainly if you are comparing your roof to engineering drawings or working with solar panel installers, who often think in degrees.

Frequently Asked Questions

Can I measure roof pitch from the ground?

No. You cannot calculate pitch accurately from ground level because the angle changes depending on where you stand and how far away you are. You must measure from the roof itself or from inside the attic using a level on an actual rafter.

What if my roof has multiple pitches?

Many homes have different pitches on different sections — for example, a main roof at 6:12 and a porch roof at 4:12. Measure each section separately. When you order materials or get repair quotes, specify which section you are asking about.

Do I need to hire a roofer to measure my pitch?

No, but it is reasonable to do so if you are uncomfortable in an attic or on a roof. A roofer's measurement takes 10 minutes and costs $75 to $150. If you are already getting a repair or replacement estimate, ask the roofer to measure the pitch as part of that visit at no extra charge.

Will my pitch change over time?

No. The pitch of your roof is set by the structure of your home and does not change unless the roof is rebuilt. Sagging or settling can happen, but that is a structural problem, not a pitch change, and it requires a structural engineer to assess.

What pitch do I need for solar panels?

Solar panels work on most pitches, but they perform best on roofs between 4:12 and 8:12 in most climates. A solar installer will measure your pitch and orientation (which direction the roof faces) as part of their site assessment. Pitch alone does not disqualify a roof from solar.