How to Measure Replacment Windows

Replacing your own windows is a cost-saving project for a moderately skilled do-it-yourselfer. It's critical that the replacement windows you buy will fit in the existing space, so measure carefully. Windows and window jambs can warp over time, so measure replacement windows at multiple spots.

Things You'll Need

• Tape measure

Show More

Instructions

1. • 1

     Measure the inside of the window from side to side at the bottom, middle and top.

   • 2

     Don't measure the trim in the window. Measure only from jamb to jamb.

   • 3

     Use the smallest of the three measurements for the width if they vary.

   • 4

     Measure from the top of the windowsill to the inside of the top of the window at two places, one on the right and one on the left.

   • 5

     Use the smaller of the two measurements.

   • 6

     Take your measurements from the inside of the house, not the outside.