Glasslock Round Lids vs Rectangle Lids: Replacement Guide
By Eco Friendly Glass Containers - Glasslock | Published: 2026-10-15
Category: Tips & Care
Learn how to identify and replace Glasslock round and rectangle lids by model number, avoid gasket-only fixes, and keep your glass containers sealed.
Quick answer
To replace a Glasslock lid, find the model number on the bottom of your container—letters followed by three digits—and match it to the correct round or rectangle lid. Round lids fit round containers; rectangle lids fit rectangular ones. Measure the container's shape and check stock before ordering, and remember that gaskets are not sold separately.
Why lid shape and model number both matter
Glasslock lids are not interchangeable between round and rectangular containers. Even if the dimensions seem close, the corner radius and sealing channel differ. The model number on the bottom of your container is the only reliable way to identify the correct replacement lid. It typically starts with letters (like OCRT) followed by three digits (like 173). This code tells you the exact container series and size. Without it, you risk ordering a lid that looks similar but will not seal.
How to find your container's model number
Turn your glass container upside down. The model number is usually embossed or printed on the bottom. It may be faint, so use a flashlight or take a photo with your phone and zoom in. If the number is worn off, measure the container's top opening and depth, then compare with product listings that show dimensions. For example, the OCRT-173 rectangle container measures 8'' x 6-1/4'' x 3'' h. Matching those dimensions to a lid listing helps narrow down options when the model number is missing.
Round vs rectangle: what changes in sealing
Round lids have a continuous circular gasket that applies even pressure when snapped on. Rectangle lids have four corners where the gasket must seal tightly; these corners are the most common leak points if the lid is warped or the gasket is worn. If you are replacing a rectangle lid, inspect the container's rim for chips or cracks—a damaged rim will prevent even a new lid from sealing properly. Round containers are more forgiving of minor rim imperfections.
What to do when the gasket wears out
Glasslock does not sell silicone gaskets as separate replacement parts. If your gasket is stretched, torn, or no longer seals, you must replace the entire lid. This is why it's worth keeping a spare lid on hand for the containers you use most. When ordering, note that the color of the lid and/or silicone gasket may vary from what you see online—this does not affect fit or function.
Step-by-step replacement process
- Locate the model number: Turn the container upside down and find the embossed or printed code (letters followed by three digits). If it's worn, take a photo and enhance it. Checkpoint: Write down the full code—you'll need it for matching.
- Determine lid shape: Confirm whether your container is round or rectangular. Do not assume a lid from another shape will fit, even if dimensions seem close. Common mistake: Trying to force a round lid onto a rectangle container.
- Match model number to lid listing: Use the model number to find the correct Round Lids or Rectangle Lids product. If the model number is missing, compare container dimensions to product specs. Checkpoint: Verify the first three digits match your container's code.
- Check stock and order: Rectangle lids and other items may be out of stock temporarily. If your size is unavailable, consider buying a spare for another container you own. Next step: Set a reminder to check back if out of stock.
- Test the new lid: Snap the lid on and press around the edges. The lid should sit flush and feel secure. If it pops off easily, the size may be wrong. Checkpoint: Fill with water, invert, and check for leaks before storing food.
Product facts
- Round Lids: Round Lids correspond to the model number located on the bottom of your glass container (letters followed by the first three digits). The color of the lid and/or silicone gasket may vary. Gaskets are not available as a separate replacement part; only the whole lid can be replaced. You must match the model number exactly. If your gasket is the only problem, you still need to buy a complete lid.
- Rectangle Lids: Rectangle Lids correspond to the model number located on the bottom of your glass container (letters followed by the first three digits). The color of the lid and/or silicone gasket may vary. Gaskets are not available as a separate replacement part. Out of Stock items are temporarily unavailable. Rectangle lids are shape-specific. Check stock before ordering, as popular sizes may sell out.
- OCRT-173 Glasslock Oven Safe Rectangle 6.3 cups: OCRT-173 Glasslock Oven Safe Rectangle 6.3 cups measures 1.6 qt., 8'' x 6-1/4'' x 3'' h. Packaging labels may vary from what is featured on the website. If your container matches these dimensions, the corresponding rectangle lid will fit. Use this as a reference when the model number is unreadable.
