| Model | Outside L × W × H | Inside at bottom L × W × H |
|---|---|---|
| Sterilite 6 Qt. 2242 | 13½ × 8 × 4⅝ | 11½ × 6 × 4¼ |
| Sterilite 12 Qt. 4243 | 16½ × 11¼ × 5⅜ | 13⅞ × 9⅛ × 4¾ |
| Sterilite 20 Qt. 2244 | 16⅜ × 11¼ × 9 | 13¾ × 9 × 8⅜ |
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Measure the shelf opening first
Write down the clear width, usable depth and height of one shelf. Measure between the parts that can actually block a box, including supports, hinges and a cabinet door that overlaps the opening. Check the narrowest point on the way in. A box that fits on the shelf still needs a route through the opening.
Choose which side will face you
A rectangular box can fit two ways. Turning its short side toward the front uses less shelf width but more depth. Draw the shelf as a rectangle and mark that orientation before comparing sizes. If you plan to pull a box out, keep its handle or gripping edge reachable. Check the lid, latches and any projecting handles against the space too.
Read the inside and outside measurements separately
The outside dimensions help you decide where a box will go. The inside dimensions help you decide what will go into it. Sterilite labels the interior figures below as measurements at the bottom. They describe that part of the container. Check the widest, longest or tallest item you want to store against the relevant inside measurement. The quart figure alone cannot tell you whether a long board game or a folder will lie flat.
Three exact boxes to compare
The selected 12-quart and 20-quart boxes both have a listed outside width of 11¼ inches. Their heights differ, and the lower-capacity box actually has the slightly larger listed interior footprint at the bottom. A larger quart figure does not automatically give a flat object a wider base to rest on. Use the dimensions in the table for the exact model, then check your largest item. Similar names and capacities can belong to different shapes.
Try a 36-inch shelf on paper
Suppose the clear shelf space is 36 inches wide, 17 inches deep and 10 inches high. Place the short side of each box toward the front. Four of the 6-quart boxes use 4 × 8 = 32 inches of width, leaving 4 inches in total. Three of either the selected 12-quart or 20-quart boxes use 3 × 11¼ = 33¾ inches, leaving 2¼ inches in total. These calculations use the published dimensions and a hypothetical shelf. They do not include an allowance for measurement differences or getting your fingers around a box.
Check the other two directions
On that example shelf, the 6-quart box leaves 3½ inches of depth. The 12-quart leaves ½ inch, and the 20-quart leaves ⅝ inch. All three are shorter than the 10-inch opening, but the 20-quart leaves only 1 inch above it. Plan to slide a box out if you cannot open its lid in place. A close result on paper is a reason to check the actual box before buying a full set.
Decide what each box will hold
Four small boxes give you four separate groups and a total labeled capacity of 24 quarts. Three of the selected 12-quart boxes give 36 quarts, while three of the 20-quart boxes give 60. Those totals compare the labeled capacities. The better choice depends on the items and how you use them. Small boxes can make sense for separate craft supplies. One larger box may suit folded items you usually take out together. Check the shelf's stated load limit before loading it.
Buy the first box before committing to a set
If you can buy one, check it on the shelf and put the intended items inside before ordering several. Confirm that you can reach it, lift it and close the cabinet door. If comparing packs, divide the total price by the number of boxes and include delivery in the comparison. Keep the model number and your shelf measurements in the same note so a later replacement matches.