Rafterly: Rafter Calculator

Enter span and pitch — get rafter lengths, plumb and seat cuts, ridge height and a fully dimensioned drawing in seconds. Gable, shed, hip with valleys, gambrel.

Rafterly is the rafter calculator built for the jobsite. Enter your span and pitch — get rafter lengths, plumb cuts, seat cuts, ridge height, and a fully dimensioned technical drawing in seconds. Read it right at the saw.

FOUR ROOF TYPES, EVERY CUT SOLVED

• Gable — common rafter length, plumb and seat cuts, birdsmouth, ridge height
• Shed — single-pitch lean-to rafters, with different wall heights handled for you
• Hip and Valley — hip rafter lengths and angles, with a one-tap toggle that mirrors the geometry for valleys
• Gambrel — dual-pitch barn roofs with an adjustable break point

JACK RAFTER CUT LISTS Hips and valleys generate a numbered jack rafter cut list — every length and every angle, ready to work straight through at the saw. No more stepping off each jack by hand.

THE DRAWING IS THE ANSWER Every calculator leads with a large, annotated 2D technical drawing rendered to engineering conventions. The member being calculated is highlighted, every dimension is labeled, and the results below simply mirror what the drawing already shows. If you can read a plan, you can read Rafterly.

MEASURE PITCH WITH YOUR PHONE The built-in inclinometer turns your iPhone into a pitch gauge. Lay it on a rafter, a roof surface, or a speed square and read the pitch as rise-over-run, degrees, or percent. Calibration included.

WORKS THE WAY YOU MEASURE

• Feet and inches with true stacked fractions down to 1/16", decimal inches, millimeters, or centimeters
• Pitch as rise/run (8/12), degrees, degrees-minutes-seconds, radians, or percent
• A purpose-built fractional keyboard — yes, with a decimal point

TAKE IT TO THE JOBSITE

• Export a PDF cut sheet: the dimensioned drawing plus the full cut table, ready to print or share
• Save projects and pick up exactly where you left off
• Native iPad layouts with Split View support — drawings render big and clean

PRIVATE BY DESIGN Everything is calculated on your device. No account, no sign-up, and your projects never leave your phone.

Know your span. Know your pitch. Rafterly does the rest.

Always verify all measurements before cutting.

Use of this app is subject to Apple’s Standard Licensed Application End User License Agreement (EULA), available in the App Store under "License Agreement" and at https://www.apple.com/legal/internet-services/itunes/dev/stdeula/