This is a preparation guide. It does not calculate order sizes or replace the selected manufacturer’s measuring instructions.
Make a window list.
Give each opening a clear name, such as “kitchen, left of sink.” Record the room, current operating style, approximate opening size and how many windows share that size. Photograph the inside, outside and any damaged areas.
Separate opening size from order size.
The dimensions of an existing opening are not automatically the dimensions to submit for a new window. An insert replacement and a full-frame replacement can require different measuring points and allowances.
Keep the original readings. Do not apply a standard deduction to every window. Confirm where to measure and who supplies the final order size for the chosen product.
Check the frame and the opening.
Look for soft wood, water staining, gaps and a frame that seems out of square. Document what you see so a qualified installer can assess whether the existing frame is suitable for the planned replacement.
Review before ordering.
- Match every measurement to a named opening.
- Confirm the measuring units and width-before-height convention.
- Verify operating direction, glass requirements and finish choices.
- Confirm final dimensions with the person responsible for installation.
- Keep a copy of the approved specifications.
The future Next Day Windows ordering process will include measurement entry. It is not available on this site yet.