How to Measure a Window Sill

When working on a remodeling project, you might work on the exterior windows and doors. You may need to replace the interior or exterior windowsills due to water damage over time. If this is the case, you must measure the existing windowsill to purchase a replacement sill. The average handyman can measure the windowsill with just a tape measure.

Remove plants and other objects before measuring the windowsill.

Step 1

Open any shade or shutter for the window unit. 

Step 2

Remove plants and other objects from the windowsill. 

Step 3

Measure the window from the left window jamb to the right window jamb.  The window jamb is the piece of wood that is perpendicular to the window. The jamb is the wood that the interior windowsill fits between. 

Step 4

Read the measurements on the tape measure for the windowsill width.  The windowsill extends past the jamb by a couple of inches on each side. Use the jamb to jamb width, however, to order the windowsill material.  The tape measure reads from left to right in inches and displays portions of an inch in 1/16ths.

Things You Will Need

  • Tape measure

About the Author

Jim Wildman served in the United States Marine Corps as a Communication Chief for 10 years. After his tour of duty in Desert Storm he attended Oklahoma State University receiving his Bachelor of Architecture. He worked as an architect for 10 years before starting his own design/build company. He began writing in 2009 for Demand Studios and published on eHow.

Photo Credits

  • flowers on the window-sill image by Daria Miroshnikova from Fotolia.com