How Much Larger Should a Door Frame Be Than the Door?

Door frames begin six inches wider than the finished door.

Proper Sizing

From the normal 16-inch spacing between wall studs, add two-by-fours so that the opening between them is 6 inches wider than the door you are installing. Add an additional two-by-four cut to 1 inch taller than the door on both interior sides of the frame. A prefabricated door will fit into this frame.

Check the Door's Manual

Some custom or nonstandard-sized doors may have other frame requirements. Check the instructions sold with the door so that you are not wasting time building an improperly-sized frame.

Bottom Line

If your door is a common or standard size, 36-by-80 in the United States, these framing instructions should work. Otherwise, check the manual or with your door's manufacturer.

References

• Aubuchon Hardware: How to Frame and Hang a Door
• Dimensions Guide: Standard Door Dimensions