How to Identify Your Toilet Tank Lid Before Buying a Replacement

August 7, 2026

Replacement toilet tank lid identification guide

Replacing a broken toilet tank lid sounds simple until you start shopping. Two lids can look almost identical in a photo and still differ enough in length, depth, corner shape, or underside profile that one will not sit correctly on the tank.

The safest way to identify a replacement is to treat the toilet like a parts system. Start with the manufacturer and tank number, then use measurements and photos to confirm the match.

1. Start with the toilet tank, not just the broken lid

If the lid is broken, missing, or has no readable number, remove it carefully and look inside the toilet tank. Manufacturers commonly place model information on the inside wall of the tank. Depending on the brand and age, the number may be stamped, molded, printed, or written in ink.

Write down every number and marking you can find. Do not assume the largest number is the lid part number. A tank model number and a lid part number are often different.

2. Find the manufacturer

Look for a brand name or logo on the tank, bowl, underside of the lid, or internal markings. Common manufacturers include American Standard, Kohler, Gerber, TOTO, Mansfield, Crane, Briggs, Sterling, Niagara, and Glacier Bay.

The manufacturer matters because identical-looking model numbers from different brands do not mean the parts are interchangeable.

3. Understand tank numbers versus lid numbers

This is one of the most common sources of ordering mistakes. The number inside the tank may identify the tank, while the replacement lid has a separate part number.

For example, an American Standard 4019 tank uses a 735122-series tank cover. A Kohler K-4620 tank uses the 84591 lid. Knowing the tank number lets you cross-reference the correct lid instead of trying to match by appearance alone.

You can see examples in our American Standard 735122 / 4019 listing and Kohler 84591 / K-4620 listing.

4. Measure the tank opening

Measurements are a confirmation tool, not a substitute for the model number. Measure the top opening of the tank from side to side and front to back. If you still have the original lid, measure its overall width and depth as well.

Use a rigid tape measure and record the measurements to at least the nearest 1/8 inch when possible. Small differences can matter because vitreous china lids rest on a specific ledge or lip.

5. Photograph the top and underside

The underside of a toilet tank lid is often more useful than the top. Ribs, feet, molded numbers, contours, and the shape of the inner lip can distinguish two lids that look nearly identical from above.

If you are documenting a lid for identification, take:

one straight-down photo of the top,
one straight-down photo of the underside,
one photo of the model numbers inside the tank, and
one photo showing your measurements.

6. Match fit before color

White, bone, biscuit, almond, linen, and older vintage colors can look very different depending on lighting and camera settings. First confirm the exact lid shape and part number. Then determine the color.

A correctly colored lid that is the wrong model is still the wrong lid.

7. Watch for model families and alternate numbers

Older toilets are especially confusing because the same lid can be searched under a tank number, lid number, toilet family name, retailer number, or an alternate formatting of the same part number. Hyphens and prefixes may also vary.

That is why FixALid product pages include compatible tank numbers and known aliases wherever we can verify them. Searching every number you found inside the tank is usually more effective than searching only for “white toilet lid.”

Common identification mistakes

Matching only by shape: many rectangular lids look alike until you compare the underside.
Using only the bowl number: the bowl and tank can have different model numbers.
Assuming a close measurement is close enough: a fraction of an inch can change the fit.
Buying by color first: fit should be confirmed before the finish.
Ignoring flush style: some dual-flush lids have button openings and are not interchangeable with standard lids.

A good identification checklist

Before ordering, try to have five things: manufacturer, tank model number, any lid number, tank/lid measurements, and clear photos of the top and underside. When those agree, the odds of a correct fit improve dramatically.

FixALid specializes in original replacement toilet tank lids, including discontinued and hard-to-find models. If you already know your number, search the site using the exact tank or lid number first.