Should I measure the frame or just the glass?

Measure the visible glass only. The new pane or IGU sits inside stops in the sash, so frame measurements will always read larger than what the glass has to be.

How accurate do my measurements need to be?

Within 1/16 inch is ideal. We still verify on site before fabricating, but a close home measurement lets us ballpark the cost and lead time on the first call.

Do I need to remove the sash to measure?

No. Measuring the exposed glass in place is enough for a phone quote. We will pop the stops on install day to confirm depth before ordering if anything looks unusual.

How to Measure a Window for Glass Replacement

Published 2026-06-15

Getting accurate measurements is the difference between a same-week install and a re-order. Whether you are calling in a fogged insulated unit or a cracked pane, three numbers get you most of the way there: width, height, and thickness. Here is exactly how we ask homeowners around Pottstown to take them.

What You Need

Grab a steel tape measure, a notepad, and a helper if the window is large. A digital caliper helps for thickness but is not required — a folded piece of paper marked at the edge of the glass works in a pinch.

Measuring Width and Height

Measure the visible glass only, not the frame. Take the width across the top, middle, and bottom of the pane, then record the smallest of the three. Do the same for height on the left, middle, and right. The smallest reading is what the new glass has to clear.

Round to the nearest 1/16 inch. Insulated units are cut to order, so an over-measurement will not fit and an under-measurement will rattle.

Measuring Thickness and Spacer

For a single pane, thickness is usually 1/8 inch (single-strength) or 3/16 inch (double-strength). For an insulated glass unit, measure the total sandwich — most residential IGUs are 5/8 inch or 3/4 inch overall. If you can see the metal spacer bar between the panes, note its color and width; that helps us match the look.

What Else to Note

Snap a photo of the window from inside and out. Mention any tint, low-E coating, grids between the panes, or tempered stamps in the corner. Doors, sidelights, and windows near tubs are typically tempered by code, and we will build the replacement to match.

Bring your numbers to /window-glass-replacement or call (901) 256-3101 and we will price the unit before we come measure to confirm.

Frequently Asked Questions

Should I measure the frame or just the glass?: Measure the visible glass only. The new pane or IGU sits inside stops in the sash, so frame measurements will always read larger than what the glass has to be.
How accurate do my measurements need to be?: Within 1/16 inch is ideal. We still verify on site before fabricating, but a close home measurement lets us ballpark the cost and lead time on the first call.
Do I need to remove the sash to measure?: No. Measuring the exposed glass in place is enough for a phone quote. We will pop the stops on install day to confirm depth before ordering if anything looks unusual.

Talk to a Local Glass Pro

Call (901) 256-3101 or request a free estimate.

94 Buckwalter Rd, Pottstown, PA, 19465
Phone: (901) 256-3101