Roof Pitch Calculator
Convert a roof's rise and run into a pitch. Enter rise and run in inches; the tool returns the pitch as an x:12 ratio, the slope angle in degrees, and the slope multiplier that scales flat area to sloped area.
What this calculator does
The Roof Pitch Calculator estimates your result instantly from the values you enter, using standard construction & home formulas. Convert a roof's rise and run into a pitch. Enter rise and run in inches; the tool returns the pitch as an x:12 ratio, the slope angle in degrees, and the slope multiplier that scales flat area to sloped area. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.
Result
About Roof Pitch Calculator
Enter the rise and run in inches. The tool scales the ratio to a twelve-run base with rise ÷ run × 12, expressing the pitch in the standard x:12 form.
It also gives the slope angle in degrees from the arctangent of rise over run, and a slope multiplier of √(rise² + run²) ÷ run for turning flat area into sloped area. It runs free in your browser.
Formula & Mathematical Calculation
Pitch Ratio = f(Rise (in), Run (in))
Calculated according to standard construction formulas implemented in the calculator core.
Calculation Example
Enter Rise 6 in and Run 12 in.
Pitch = 6 ÷ 12 × 12 = 6:12.
Angle = arctan(6 ÷ 12) = 26.57°.
Multiplier = √(6² + 12²) ÷ 12 = √180 ÷ 12 = 1.118.
Key Benefits
- Expresses pitch in the standard x:12 ratio contractors use
- Adds the slope angle in degrees for anyone thinking in angles
- Provides the slope multiplier needed to convert flat area to sloped area
- Free and runs in the browser with no sign-up
How to Use this Calculator
-
Enter the rise
Type the vertical rise in inches into the Rise (in) field. -
Enter the run
Type the horizontal run in inches into the Run (in) field. -
Calculate
Press Calculate and read Pitch Ratio, Angle, and Slope Multiplier in the result boxes.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
- Results use standard published formulas and account only for the values entered above.
- Rounding is applied for display; the underlying calculation uses your full precision.
- Results are returned in the same units you enter, unless the tool states the output unit.
What it does not cover
- Roof Pitch Calculator produces a calculated result for reference and learning, not a certified or official measurement.
- Real-world outcomes differ when tolerances, rounding rules or local standards apply.
- Definitions and standards vary by region and change over time; verify the convention that applies to your case.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For work where the result carries real consequences, confirm it against an authoritative source.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.