Gather replacement glass, glazing points, putty or glazing compound, putty knife, glass cutter, measuring tape, utility knife, screwdriver, pliers, gloves, and safety glasses
Remove the window sash if needed
Take out the broken glass carefully
Remove old glazing putty, glazing points, and any remaining fragments
Measure the opening accurately
Cut the replacement glass to size or have it cut to fit
Clean the frame and check for damage
Apply a thin bed of glazing compound or putty in the frame
Set the new glass into the opening
Secure the glass with glazing points or clips
Apply glazing compound around the edges
Smooth the putty with a putty knife
Let the glazing compound cure fully
Reinstall the sash if removed
Clean the glass and inspect the seal