A 4/12 roof pitch can also be expressed as 4 over 12 and when you're talking to a roofer, this is the most common way you'll hear it explained because it's easy to say in conversation.
Another way to express a 4/12 pitch is "4 and 12."
In this pitch, the four is your roof's rise and the twelve is the roof's run.
The roof's incline increases four feet for every 12 feet of horizontal measurement.
What angle is a 4 over 12 pitch?
Roofs with a pitch of 4/12 are approximately 18.4 degrees, depending on how exact you'd like to be in your measurement.
Check out our roof angle chart for more examples of the exact angles (expressed in degrees) of common roof pitches.
Above is a roof replacement in Fitchburg, Massachusetts we completed this year. The entire roof is a 4/12 pitch and you'll see in the picture that it isn't very steep. When re-roofing a home with a 4 and 12 pitch, you don't have to be as careful of your footing compared to when you're roofing a steeper pitch like the roof below.
Part of the roof on this roofing project we completed in Roslindale, MA was a 4 over 12 dormer. You can see it marked by the blue arrow on the right that says 4/12.
Compared to the first example on this page (the gray roof), you can see how much steeper the entire roof is here. That's because the majority of the home had a 12/12 pitch, which made it a steep slope (and a much more dangerous job for our crew).