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How to Measure for a Replacement Pool Skimmer Lid

November 03, 2026• By The Metal Casting Store•Buying Guides Pool Deck Skimmer Lids

A skimmer lid is one of the few parts of a pool deck people step on every day, so a cracked or faded plastic cover stands out. Replacing it with a solid cast brass or aluminum lid is a quick upgrade, but only if the new lid fits. Skimmer lids come in close sizes (9-7/8", 10-7/16" and 10-1/2" are all common), so a quick look isn't enough. Here's how to measure.

What you'll need

A tape measure that reads to 1/16"
A flashlight
A phone to photograph the lid, the collar and the opening

Step 1: Round or square?

Start with the shape. Most residential skimmers use a round lid, while some pools, especially older or commercial ones, use a square frame and lid. Shape decides which part of our catalog to shop:

Round lids: 9-7/8", 10-7/16" and 10-1/2" lids, plus an 8-1/4" AutoFill lid.
Square frames: 11", 13" and 14-3/4" square frames with matching lids, plus a 7-3/4" square AutoFill collar.

Step 2: Measure the lid itself

Lift the old lid out and measure straight across its widest point, edge to edge, through the center. Measure two or three times across different points. A worn plastic lid can warp slightly, so go with the largest consistent reading.

Don't measure the hole in the deck. The lid sits on a ledge inside the collar, so the opening is always smaller than the lid. Measuring the hole is a common reason people end up with a lid that's too small.

Step 3: Check the collar

The collar is the ring set into the concrete that the lid rests in. If your collar is cracked, loose or the wrong color, replace it with the lid. You'll need two more numbers:

Outside diameter (OD): measure across the outer edge of the collar where it meets the deck. Our collars come in 10-1/2", 11" and 11-1/4" OD, plus a 7-5/8" OD AutoFill collar.
Depth: measure from the deck surface down to the bottom of the collar wall. Our 10-1/2" collars for 9-7/8" lids come in 1-1/2", 2" and 2-1/2" depths, so measure this one carefully.

If the collar is solid and you're happy with it, you only need the lid.

Step 4: Is it an AutoFill?

Many pools have a second, smaller lid near the skimmer that covers the automatic water leveler. AutoFill lids are smaller than skimmer lids. Ours fit a 7-5/8" round collar or a 7-3/4" square collar, and there's also an 8-1/4" round AutoFill lid. Measure it the same way, and note whether it sits in a round or square collar and whether it's held down with screws.

Step 5: Compare against the product diagram

Every skimmer lid on our site has a Diagram and a Product Fact Sheet link in the description. Hold your measurements up against the drawing before you order. If your numbers fall between two sizes, send us your measurements and a photo and we'll confirm the right fit.

Picking a finish

Once the size is right, the fun part is the look. Every lid is cast solid in aluminum, red brass or yellow brass, with face patterns including diamond, waffle and leatherette. You can also order a lid with a custom letter or house number cast into it.

Aluminum is the lightest and most affordable option. Brass costs more (for example, our 9-7/8" diamond lid is $123 in aluminum and $175 to $178 in brass) and develops a warm, aged look over time. Our brass vs. aluminum guide covers the trade-offs in more detail.