What does the number on the bottom of a Pyrex bowl mean?

Author: Elisabeth Gutkowski  |  Last update: Wednesday, June 18, 2025

Pyrex dishes also hide a little secret code: Many contain a three- or four-digit number that corresponds to a specific dish. A series of Mixing Bowls will feature 401 (1.5 pint), 402 (1.5 quart), 403 (2.5 quart), 404 (4 quart). The iconic two-quart green-and-white casserole dish is a 232.

How can you tell how old a Pyrex bowl is?

The best way is to look at the bottom of the product. My vintage Pyrex, which is at least 40 years old, and definitely boro-silicate, reads “Not For Lab Or Stovetop Use - Corning N.Y. - U.S.A. - 516 - PYREX.” Newer products made of soda-lime glass do not read Corning N.Y., nor are they made by Corning.

How to tell if Pyrex is valuable?

We're all thinking the same thing: Is the Pyrex sitting in my basement worth any money? A few clues in the product's design key us into the possible value: the condition and colorway. You'll want to try and find vintage dishes made between 1915 and 1970, as experts tell TODAY that these are the priciest of all.

What size is Pyrex 444?

They are numbered as follows: 401 (1.5 pt), 402 (1.5 qt), 403 (2.5 qt), 404 (4 qt). The second type of mixing bowls are the Cinderella Mixing Bowls. These have handles and pour spouts on the sides. They are numbered as follows: 441 (1.5 pt), 442 (1.5 qt), 443 (2.5 qt), 444 (4 qt).

What is the most sought after Pyrex?

Patterned Pyrex—such as the 1956 Pink Daisy or the 1983 Colonial Mist colorways—tend to be valuable as a collector's item. Other popular patterns include the 1957 Butterprint, which features an Amish couple and their crops, and has been valued at a few hundred dollars.

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What do numbers on the bottom of Pyrex mean?

Pyrex dishes also hide a little secret code: Many contain a three- or four-digit number that corresponds to a specific dish. A series of Mixing Bowls will feature 401 (1.5 pint), 402 (1.5 quart), 403 (2.5 quart), 404 (4 quart). The iconic two-quart green-and-white casserole dish is a 232.

What is the holy grail of Pyrex?

A highly-coveted pattern, the Atomic Eyes Chip and Dip is the holy grail for some Pyrex collectors. Released in the 1950s, some of the bowls feature a Pyrex stamp while others don't.

Are Pyrex bowls numbered?

Each Pyrex piece is assigned a model number, though some of the earliest sets of color ware pieces do not have them. Model numbers are typically found on the bottom of your glassware, though sometimes they are located elsewhere—look for them above the trademark on your dishes, and around handles and edges of lids.

What is the oldest piece of Pyrex?

In 1915, the company launched its first Pyrex line (Pyrex combined "pie" and "Nonex") with 12 pieces, including pie plates and a loaf pan. The 8-ounce liquid measuring cup came out 10 years later; early versions had a closed, D-shaped handle and tick marks made out of molded glass.

What is a Cinderella Pyrex bowl?

Along with Butterprint, Gooseberry was one of the first patterns debuted on the new “Cinderella Bowls.” Cinderella Bowls were a series of large nested mixing bowls with a handle or spout on each side, which were designed by John Philip Johnson.

How can you tell the difference between Pyrex and vintage Pyrex?

How can you tell if a piece is real vintage Pyrex? The secret is simple—check the logo. If the brand name is in all capital letters, it's vintage Pyrex. If it's all lowercase, it's modern.

What is the Lucky in Love casserole dish?

The Lucky In Love design is printed on the one-quart Round Casserole (473) and remains one of the most elusive Pyrex designs ever created by Corning Glass Works. Released in 1959, Lucky In Love is most likely a limited release product or even a test piece.

Can you put Pyrex glass in the microwave?

The USDA Food Safety and Inspection Service has deemed Pyrex as microwave safe. There are some things you need to know though! Pyrex is made of either borosilicate or soda lime glass and is heat resistant up to 425 degrees Fahrenheit, making it a good option for microwaving.

When should you throw away Pyrex?

Baking glassware such as Pyrex dishes in usable condition should be donated to local thrift stores or otherwise reused. If unusable they should be thrown away in the trash. They should not be added to curbside recycling. They are made of a different material than glass bottles and jars.

How to identify good Pyrex?

If the logo is in upper case lettering, PYREX, it's most likely made of borosilicate, and thus safer. The lowercase lettering is most likely made of soda-lime glass, so take extra care after any high-heat cooking.

How can you tell how old a glass bowl is?

A simple way is to compare any glass you think is antique with a more modern glass item. Antique glass is usually heavier. Other indicators to look out for are: The patina: older glass tends to show signs of use and passing time - so see if there are any small flakes, scratches and chips, or missing gilt.

When did they stop making Pyrex?

Corning divested itself of the Corning Consumer Products Company (now known as Corelle Brands) in 1998 and production of consumer Pyrex products went with it. Its previous licensing of the name to Newell Cookware Europe remained in effect.

Are old Pyrex bowls safe to use?

As long as you follow the same guidelines above, vintage Pyrex is A-OK to go in the oven and can be used in oven temperatures up to 425ºF (and skip the broiler). There is one caveat to using your vintage Pyrex, though: Do not use any vintage dishes that are chipped or cracked—in the oven or otherwise.

What does jaj mean in Pyrex?

JAJ (short for James A Jobling) were the producers of PYREX tableware, casserole dishes and other bakeware in the United Kingdom from 1922 until the plant (in Sunderland, England) closed in 2007.

What are the numbers on the bottom of Pyrex?

One of the ways that collectors know what to look for is the three or four-digit number codes pressed into the bottom of each piece. If you've ever flipped over your pie plate or casserole dish and wondered what all those numbers are about, they're simply product codes that are assigned to each style and size of dish.

How do you date a Pyrex bowl?

Vintage Pyrex Stamp and Logo

Flip over your piece and look at it carefully. It will have a stamp that can help you date it: 1940s and 1950s - The oldest Pyrex markings should be on the bottom of glass pieces and feature Pyrex in all capital letters inside a circle with CG for Corning Glassworks.

How old are primary color Pyrex bowls?

Colored Pyrex kitchenware was introduced in 1947. These appealing mixing bowl sets, made from 1949 to 1957, were among the most popular of Corning's Pyrex products ever made. Corning Glass Works' heat-resistant glass bakeware, called Pyrex, was introduced in the mid-1910s.

What is the most collectible Pyrex?

Some of the most elusive Pyrex pieces go for hundreds of dollars, and there are even anecdotes of collectors bidding thousands for rare pieces. A rare Lucky in Love Pyrex casserole dish from 1959—what might have been only a test pattern, made of shamrocks and hearts—sold for $5,994 in a 2017 Goodwill auction.

Which Pyrex is the real Pyrex?

If it's all caps “PYREX,” it's vintage, made of borosilicate. If it's lower case “pyrex,” it's new, and it's soda lime.

Which Pyrex logo is better?

Here's where the branding comes in. All-caps PYREX, which is sold and made in France, is still made of borosilicate glass. But any Pyrex that's all lowercase — a recent change in branding — is soda-lime glass, which isn't designed to withstand drastic temperature changes.

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