Method 1: Level + Tape Measure (Most Accurate)
This is the go-to method most pros use. You need a 12-inch level (or any level) and a tape measure.
1. Place the level on the roof surface so one end touches the shingles.
2. Hold it level (bubble centered) — the other end will be floating above the roof.
3. Measure 12 inches along the level from the end touching the roof.
4. At that 12-inch mark, measure straight down to the roof surface.
5. That measurement in inches is your pitch. If it's 6 inches → 6/12 pitch.
Method 2: From the Attic
If you can get in the attic, you can measure the pitch on a rafter without going on the roof.
1. Hold a level against the bottom of a rafter.
2. Measure 12 inches along the level from where it touches the rafter.
3. Measure straight up from that point to the rafter. That's your pitch.
Method 3: Speed Square
A speed square (rafter square) has pitch markings built right in.
1. Place the lip of the speed square on the roof edge or a rafter.
2. Let a plumb bob or level hang from the pivot point.
3. Read the pitch directly off the scale on the square.
Method 4: From the Ground
If you can see the gable end of the house, you can estimate from the ground.
1. Stand back and take a photo of the gable end straight-on.
2. On the photo, measure the horizontal run from the eave to directly below the ridge.
3. Measure the vertical rise from the eave line to the ridge. Divide rise by run and multiply by 12.
The level method on the roof is the fastest and most accurate. Keep a small torpedo level in your truck — it takes 30 seconds. If you don't have a level, many free phone apps can act as a level too.
