How to Measure for Curtains for Patio Doors? | Get the Right Fit

Getting the measurement right for patio door curtains comes down to one shift in thinking: stop measuring the glass and start measuring the hardware. The rod or track width, its height, and the fullness of the panels you choose all decide whether your curtains clear the door handles when open or block half the light. Before you buy anything, grab a metal measuring tape and follow the steps below. If you are comparing panel styles and materials while you plan, our roundup of the best curtains for patio doors is a useful starting point.

How Wide Should Curtains Be for a Patio Door?

The width starts with the rod span, not the door. Measure the planned rod or track from end to end, excluding any finials or decorative end caps. If the rod is already installed, simply measure the full span of the rod itself between the brackets.

For a new installation, the rod should extend 6 to 10 inches past the door frame on each side. That extra width is stack-back clearance—the space where panels rest when pulled open so they completely clear the glass and the door handle. A rod that ends at the frame leaves fabric blocking part of the opening and cuts off natural light and foot traffic.

Once you have the rod width, that is still not the curtain width. For a standard gathered look, the total panel width should be roughly 1.5 to 2 times the rod width. Outdoor curtain guides often suggest the same range. A heavy, lined panel can sit at the lower end; a lightweight sheer will look fuller at the higher end.

How Long Should Patio Door Curtains Be?

Measure the drop from the top of the rod or track down to the desired hem point. Assume the rod will sit 4 to 6 inches above the top of the door frame unless the hardware dictates otherwise.

For patio doors, floor-length is the standard recommendation. It gives a clean line and keeps panels from billowing into the door track. Most guides suggest letting the hem float about ½ to 1 inch above the floor so fabric does not drag on the threshold or any uneven spots. Choose the float distance by looking at the highest point of the floor along the whole span, not just the lowest corner.

If you prefer the fabric to just skim the floor, add that small allowance into the drop measurement rather than ordering a ready-made panel that pools. A small puddle of fabric near a sliding door track collects dirt and can catch under the door wheels, so a shorter float is the safer choice for this location.

What Else Needs Measuring Before You Buy?

A patio door is rarely a plain rectangle, so check the area around it before finalizing the dimensions. At minimum, look for these common obstructions:

• Door handles and locks. Add enough stack-back width so open panels clear the handle projection completely.
• Floor conditions. Measure the drop at both sides and the middle; a sloped threshold changes the effective hem height.
• Trim and railings. A decorative rod or a valance can interfere with crown molding or a railing cap.
• Multiple openings. French doors or a multi-panel slider need each section measured individually. Label each set of numbers so you do not mix panels up.

Measuring one side of the door and assuming the other matches is a common trap. Door frames settle, floors slope, and sliders can sit slightly crooked in the rough opening. Take each dimension in at least two spots and use the largest width and the highest floor point for your final numbers. A metal tape measure gives the most accurate read over a long span because it does not stretch or droop like a cloth version.

Write down every number before you shop, and round up rather than down when you are between sizes on a standard panel. The result is a curtain that opens fully clear of the glass, hangs evenly above the floor, and still has enough gather to look intentional on a wide door.