What Size Are Bassinet Sheets? | Measure First, Buy Second

Bassinet sheets typically run 32″ x 16″ or 33″ x 17″ with 4″ pockets, but sizes vary by brand and mattress shape.

For the full breakdown, see our best 100% Cotton Bassinet Sheets guide.

If you’re shopping for bassinet sheets, the honest answer to “what size are bassinet sheets” is that there isn’t one standard. Unlike crib mattresses, which follow a near-universal 28″ x 52″ size, bassinet manufacturers build their mattresses to their own specs. That means a sheet that fits one bassinet perfectly can slide right off another. The only reliable way to get the right size is to measure your mattress, not the frame, before you buy.

Why Bassinet Sheets Aren’t One-Size-Fits-All

Bassinet mattresses come in several shapes — rectangle, oval, round, and hourglass. Each brand chooses its own dimensions, so two bassinets sitting side by side could easily need different sheets. Guava Family support states its bassinet sheets fit a 20.5″ x 28.5″ mattress, while Snüz sells fitted sheets measuring 16″ x 30″ to 17″ x 31″. Those are both bassinet sheets, and neither would fit the other’s bassinet.

Even sheets marketed as “universal” only promise a fit within the seller’s stated measurement range, so treat that label as a starting point, not a guarantee.

For crib sheets, you’ll commonly see 28″ x 52″ — don’t assume that transfers to a bassinet.

The Sizes You’ll Actually See In Stores

Most U.S. retailers sell bassinet sheets in one of two common dimension sets. Here’s what you’ll typically find:

• 32″ x 16″ x 4″ — one of the most common listings; fits rectangle, oval, and hourglass mattresses up to 4 inches thick.
• 33″ x 17″ x 4″ — the other frequent size, also fitting oval, hourglass, and rectangle shapes.

Beyond those, you’ll see product-specific sizes. One brand’s sheet fits 15″ x 33″ (38 x 84 cm) mattresses, and Guava’s fits 20.5″ x 28.5″. Consumer guides sometimes cite 30″ x 18″ as a typical size. The range is wide because the category is wide.

Some non-U.S. listings use deeper pockets, around 13 cm or 18 cm, which points to one of the most common fit problems: depth. Most U.S. sheets max out at 4 inches of pocket depth, so if your mattress is thicker, your sheet won’t grip properly.

How To Measure Your Bassinet Mattress

Skip the guessing and get the exact numbers. Here’s the quick routine before you shop for pre-folded sheets or anything claiming “standard fit”:

1. Lay the mattress flat. Remove any cover or pad first.
2. Measure length and width. Use a fabric tape measure across the longest and widest points, in inches.
3. Measure depth. Push the tape from the top surface straight down to the bottom edge.
4. Note the shape. Check if the mattress is oval, hourglass, round, or rectangular — shape affects fit as much as numbers do.
5. Compare to the seller’s stated mattress dimensions, always verifying that your numbers fall inside their range. If you can’t find the info online, check the product manual or the mattress label itself for printed measurements.

Once you have your measurements, the sheet selection becomes straightforward: pick one whose stated dimensions match yours, with a pocket depth at least as deep as your mattress thickness. If your mattress is 5 inches thick, a sheet with 4-inch pockets won’t stay put. If you’re ready to trade up, our roundup of the best 100% cotton bassinet sheets is a solid place to start your search.

Can One Sheet Fit Different Bassinets?

Sometimes, but only within limits.

The bigger trap is proprietary sizing. Some bassinets, particularly bedside and co-sleeper models, are built with custom mattresses and only work with the brand’s own sheets.

When in doubt, buy from the bassinet’s own manufacturer, or check their support documentation for the exact mattress dimensions they design around.