BuildCalc
Roof Pitch Calculator
Project Calculators

Roof Pitch Calculator

Convert between roof pitch, degrees, and percentage. Calculate rise and run.

Area Multiplier: multiply your floor footprint by this number to get actual roof surface area.

Sponsored
Lowe'sIn-store pickup available
Roofing shingles, underlayment & flashing — get it done right.
Shop Roofing at Lowe's →

How to use the roof pitch calculator

  1. Enter your pitch in X:12 format — a 6:12 pitch rises 6 inches for every 12 inches of horizontal run.

  2. Or enter degrees if you measured the angle directly, or percentage if you're working from engineering drawings.

  3. Read the converted values: the calculator shows all three formats plus the roof area multiplier.

  4. Use the multiplier to convert your flat (footprint) area to actual roof surface area for ordering shingles or metal roofing.

Common uses

  • Converting pitch to degrees for rafter cuts and templates
  • Calculating actual roof area for shingle and underlayment orders
  • Verifying slope meets building code for your roofing material

Frequently asked questions

What is a 4:12 roof pitch?
A 4:12 pitch rises 4 inches for every 12 inches of horizontal run. That's a 18.4° angle and a fairly gentle slope — common on ranch-style homes.
What's the minimum roof pitch for shingles?
Most asphalt shingle manufacturers require at least a 4:12 pitch. Low-slope roofs (2:12 to 4:12) need special low-slope shingles or a different roofing system entirely.
How do I measure my existing roof pitch?
Hold a level horizontally against the roof surface. Measure 12 inches out from the wall (the run), then measure the vertical distance up to the underside of the level (the rise). That rise/12 is your pitch.

Not sure whether to DIY this project?

Read our project-by-project guide on when to hire a contractor vs. do it yourself.

Read the guide →

About this calculator

Enter pitch as X:12, an angle in degrees, or a percentage to instantly get all other values. Also calculates the roof area multiplier factor for material estimates.

All results are estimates. Verify quantities with your local supplier and confirm measurements before purchasing materials. Requirements vary by region and project type.

← All Calculators

Runs entirely in your browser - no data is sent anywhere