Free roof pitch calculator. Enter rise and run, a degree angle, or a pitch ratio to instantly get pitch ratio, angle in degrees, slope percentage, and rafter length. Includes a live SVG roof diagram, a reference chart of 20+ common roof pitches, and a blog covering roofing guides. All calculations run in your browser — no account needed, no ads, completely free.

Roof Pitch Calculator is a free, browser-based tool designed for homeowners, contractors, roofers, and anyone working on a roofing project. Whether you are planning a new build, replacing shingles, installing solar panels, or simply trying to understand your roof, this calculator gives you instant, accurate results across multiple input formats.

What makes Roof Pitch Calculator unique is its three-way input flexibility. Most roof pitch tools only accept a single format, leaving users to manually convert between systems. Roof Pitch Calculator accepts all three common formats interchangeably:

1. Rise and Run — Enter the vertical rise and horizontal run in any unit. The calculator instantly derives the pitch ratio, angle in degrees, slope percentage, and rafter multiplier.

2. Angle in Degrees — Enter the roof angle measured with a digital inclinometer or protractor, and the calculator converts it to all other formats including the standard X:12 pitch notation used by contractors.

3. Pitch Ratio (X:12) — Enter the pitch in the standard X:12 format (e.g., 6:12, 4:12, 12:12) that appears on blueprints and building codes.

All three input modes update results in real time as you type — no submit button needed.

Output Values:

- Pitch Ratio (X:12 notation)

- Angle in Degrees

- Slope Percentage

- Rafter Multiplier (for quick rafter length calculations)

- Rafter Length (when optional roof span is provided)

- Pitch Category (Flat, Low, Conventional, or Steep)

Live SVG Roof Diagram: As you type, a dynamic SVG cross-section diagram updates in real time to visually represent the pitch. Angle labels, rise and run dimensions, and the rafter line all update live — helping users quickly grasp the steepness of their roof.

Reference Chart: The tool includes a built-in reference chart of over 20 common roof pitches organized by category (flat, low slope, conventional, and steep). Each entry shows the pitch ratio, angle, slope percentage, rafter multiplier, and common use cases such as shingle types, drainage requirements, and regional preferences.

Blog and Educational Resources: Roof Pitch Calculator includes a growing blog with roofing guides covering topics such as what roof pitch means, how to measure pitch from inside an attic, which pitches work with metal roofing, how to calculate rafter length from scratch, shed roof pitch considerations, and regional pitch recommendations by climate zone.

Privacy and Performance: All calculations are performed entirely in the browser using JavaScript. No data is collected, no account is required, and no tracking cookies are set. The tool loads instantly on any device and works offline after first load.

Built with modern web technologies including Next.js and Tailwind CSS, the tool is mobile-responsive, fast, and accessible. The interface uses clean typography and minimal design to keep the focus on the calculations.