Quick Answer

Choose the Glasslock 20pc Oven Safe Box Set if you want one extra rectangular 1.6-cup container and a square 6.0-cup container for larger leftovers or meal prep. Choose the 18pc set if you prefer a round 3.1-cup container and want to save about $2.68 at catalog prices. Both include matching lids and oven-safe glass, so the right pick depends on the shapes and sizes you will actually use.

What You Get in Each Set

The 20pc set includes rectangular containers in 1.6 cups (2), 3.5 cups (1), square containers in 1.5 cups (2), 3.3 cups (1), 6.0 cups (1), round containers in 0.7 cups (1), 1.6 cups (2), plus 10 matching lids. The 18pc set includes rectangular containers in 1.6 cups (1), 3.5 cups (2), 6.3 cups (1), square containers in 1.5 cups (1), 3.3 cups (1), round containers in 0.7 cups (1), 1.6 cups (1), 3.1 cups (1), plus 9 matching lids. The main differences are the extra rectangular 1.6-cup container and the square 6.0-cup container in the 20pc set, versus a round 3.1-cup container and a larger rectangular 6.3-cup container in the 18pc set.

How to Match Sizes to Your Cooking

If you often pack single servings of leftovers or sides, the extra 1.6-cup rectangular container in the 20pc set gives you one more small option without buying a separate piece. If you bake or roast and want a square shape for brownies, lasagna portions, or layered dishes, the square 6.0-cup container in the 20pc set is a better fit than the round 3.1-cup container in the 18pc set. The 18pc set’s rectangular 6.3-cup container is slightly larger than the 20pc set’s largest rectangular container (3.5 cups), which helps if you store bigger batches of soup, stew, or casseroles. The round 3.1-cup container in the 18pc set works well for leftovers that you reheat in the microwave, though both sets are oven safe.

Lids and Storage

Both sets come with matching lids—10 for the 20pc set and 9 for the 18pc set. The lids are designed for the specific container shapes and sizes, so you cannot swap a square lid onto a rectangular container. If you plan to stack containers in the fridge or freezer, the rectangular and square shapes in both sets stack more efficiently than round containers. The round containers are better for liquids or foods you want to stir, but they leave more unused space on a shelf.

Price and Value

At catalog prices, the 20pc set is $33.49 (compared to $49.99) and the 18pc set is $30.81 (compared to $45.99). The 20pc set costs about $2.68 more but gives you two extra pieces—an additional rectangular 1.6-cup container and a square 6.0-cup container—plus one extra lid. If you would use those sizes, the 20pc set offers more flexibility per dollar. If you prefer the round 3.1-cup container and the larger rectangular 6.3-cup container, the 18pc set is the better value for your needs.

Decision Rules

  • If you pack many single servings: The 20pc set has two 1.6-cup rectangular containers versus one in the 18pc set. Choose the 20pc set for lunch prep or small leftovers.
  • If you bake square dishes: The 20pc set includes a square 6.0-cup container; the 18pc set does not have a square container larger than 3.3 cups. Choose the 20pc set for brownies, small casseroles, or layered meals.
  • If you store large batches: The 18pc set has a rectangular 6.3-cup container, which is larger than any rectangular container in the 20pc set (largest is 3.5 cups). Choose the 18pc set for soup, stew, or meal-prep batches.
  • If you prefer round containers for liquids: The 18pc set includes a round 3.1-cup container; the 20pc set’s round containers top out at 1.6 cups. Choose the 18pc set if you reheat or store round portions.
  • If you want the lowest price: The 18pc set costs $30.81 versus $33.49 for the 20pc set at catalog prices. Choose the 18pc set if the extra 20pc sizes are not essential.

Product Facts

  • 11293 – 20pc Glasslock Oven Safe Box Set: 20pc Glasslock Oven Safe Box Set: Rect. 2pc-1.6c / 1pc-3.5c; Square 2pc-1.5c / 1pc-3.3c / 1pc-6.0c; Round 1pc-0.7c / 2pc-1.6c; 10 matching lids. Includes two small rectangular containers and a square 6.0-cup container, which suits portioned meals and square baking dishes.
  • 11292 – 18pc Glasslock Oven Safe Box Set: 18pc Glasslock Oven Safe Box Set: Rect. 1pc-1.6c / 2pc-3.5c / 1pc-6.3c; Square 1pc-1.5c / 1pc-3.3c; Round 1pc-0.7c / 1pc-1.6c / 1pc-3.1c; 9 matching lids. Offers a larger rectangular 6.3-cup container and a round 3.1-cup container, which helps with bigger batches and round leftovers.

Who Each Set Fits

Best for

  • Singles or couples who pack multiple small portions and want an extra 1.6-cup rectangular container.
  • Home cooks who bake square dishes and need a square 6.0-cup container.
  • Anyone who wants the most pieces and lids for a few dollars more.

Not for

  • Large families who need a bigger rectangular container for batch cooking—consider the 18pc set or a set with a 6.3-cup rectangle.
  • Shoppers who mainly store round leftovers and want a 3.1-cup round container.
  • Budget-focused buyers who will not use the extra 20pc sizes.