How do I use this for rafter cuts?

The angle output is the bevel angle for plumb cuts. Use the pitch to set framing squares.

Is pitch the same as slope percent?

Pitch is rise over 12 inches of run (e.g., 6/12). Slope percent is rise ÷ run expressed as a percentage.

Can I enter metric measurements?

Yes. Use the same units for rise and run; the ratio is unitless and still produces the correct pitch and angle.

What pitch do asphalt shingles require?

Many shingles allow down to 2/12–4/12 with special underlayment; check manufacturer specs and local code for exact requirements.

Does this account for ridge thickness or seat cuts?

No. It only gives pitch and angles. Layout adjustments for ridge or birdsmouth cuts require framing references.

construction calculator

Roof Pitch Calculator

Find roof pitch, slope percent, and angle from rise and run.

Results

Pitch (in 12): 6.00
Slope (%): 5000.00%
Angle (degrees): 26.57

How to use this calculator

Enter the rise and run of the roof segment (in the same units).
See the pitch per 12 inches, slope percentage, and bevel angle.
Use pitch or angle when setting saw bevels, framing squares, or material specs.

Inputs explained

Rise: Vertical change over the run. Enter in inches for typical roof pitch values.
Run: Horizontal distance that the rise occurs over, usually 12 inches for standard pitch notation.

How it works

Slope percent = rise ÷ run.

Pitch in 12 uses run normalized to 12 inches. Angle uses arctangent of rise/run.

Formula

Slope % = (rise / run) × 100
Angle = arctan(rise / run)

When to use it

Determining if your roof meets minimum slope requirements for shingles, metal, or membranes.
Setting bevel angles for plumb cuts on rafters and fascia.
Communicating roof slope to suppliers, inspectors, or installers.

Tips & cautions

Keep units consistent—enter both rise and run in inches or both in feet, then interpret the pitch result accordingly.
Use a digital level or framing square to measure existing roofs accurately before cutting.
If you only know pitch (e.g., 6/12), enter rise=6 and run=12 to confirm angle and slope percent.
Does not size rafters or account for overhangs; use the rafter length calculator for that.
Material suitability still depends on local code, climate, and manufacturer specs beyond slope alone.
Assumes a straight run without hips/valleys; complex roofs need separate measurements per plane.

Worked examples

6 in rise over 12 in run

Pitch = 6/12
Slope ≈ 50%
Angle ≈ 26.6°

4 in rise over 12 in run

Pitch = 4/12
Slope ≈ 33.3%
Angle ≈ 18.4°

Deep dive

This roof pitch calculator converts rise and run into pitch (in 12), slope percentage, and roof angle. Enter rise and run to get the numbers you need for framing, bevel cuts, or checking material requirements.

Use it to confirm a roof meets shingle or metal slope minimums and to set saw angles for rafters or fascia. Keep rise and run in the same units for accurate results.

FAQs

How do I use this for rafter cuts?: The angle output is the bevel angle for plumb cuts. Use the pitch to set framing squares.
Is pitch the same as slope percent?: Pitch is rise over 12 inches of run (e.g., 6/12). Slope percent is rise ÷ run expressed as a percentage.
Can I enter metric measurements?: Yes. Use the same units for rise and run; the ratio is unitless and still produces the correct pitch and angle.
What pitch do asphalt shingles require?: Many shingles allow down to 2/12–4/12 with special underlayment; check manufacturer specs and local code for exact requirements.
Does this account for ridge thickness or seat cuts?: No. It only gives pitch and angles. Layout adjustments for ridge or birdsmouth cuts require framing references.

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Confirm local code requirements for minimum slopes and materials.