CPSC crib mattress standard part 1241.

Scope: which mattresses

Section 1241.1 says: "The scope of this standard for crib mattresses includes all crib mattresses within the scope of ASTM F2933, Standard Consumer Safety Specification for Crib Mattresses, including: Full-size crib mattresses, non-full-size crib mattresses, and after-market mattresses for play yards and non-full-size cribs." That list matters because a mattress sold on its own for a travel crib or play yard is inside the standard, not only the mattress that ships with a crib. Part 1236, the infant sleep products standard, adds a sentence pointing the other way: crib mattresses that meet the requirements of ASTM F2933 are not covered by that standard (1236.2(b)(4)).

The requirement and the edition

Under 1241.2(a), "each crib mattress must comply with all applicable provisions of ASTM F2933-25," which 1241.3 identifies as approved October 1, 2025. The section was most recently amended on February 12, 2026 (91 FR 6515 and 6516), when that edition and the other two referenced standards were updated: ASTM F406-24 for non-full-size cribs and play yards and ASTM F2194-25, Standard Consumer Safety Specification for Bassinets and Cradles, approved August 1, 2025. The standards themselves are not reproduced in the CFR; each is available to read free from ASTM and may be inspected at the CPSC and the National Archives.

Full-size mattress size and corner gap

In place of F2933 section 5.6.1.1, the CFR substitutes its own text: "The dimensions of a full-size crib mattress shall measure at least 27 1/4 in. (690 mm) wide and 51 5/8 in. (1310 mm) long. When the mattress with the test mattress sheet is placed against the perimeter and in the corner of the crib, the corner gap shall not exceed 3.15 in. (80.0 mm). Dimensions shall be tested in accordance with 6.2." Three numbers, then: width at least 27.25 inches, length at least 51.625 inches, corner gap at most 3.15 inches. There is no stated maximum size; the gap limit is what limits how undersized a mattress can be for its crib.

How the corner gap is measured

The CFR adds text to F2933 section 6.2.3. A test mattress sheet is placed so that each edge is wrapped fully around and under the mattress. The tester then measures "the shortest gap between the mattress and the projected crib corner after the dimensions of the mattress have been recorded." The projected crib corner is "located 53 in. plus or minus 1/8 in. (1346 mm plus or minus 3.2 mm) from Wall C and 28 5/8 in. plus or minus 1/8 in. (727 mm plus or minus 3.2 mm) from Wall D," as shown in Figure 12, and the mattress is not moved during measurement. The mattress is then rotated 180 degrees so the opposing corner is adjacent to Walls C and D, and the measurement is repeated.

The sheet is specified too: it "shall be 100% cotton and fitted for the mattress to be tested," washed in hot water (50 degrees C [122 degrees F] or higher) and dried a minimum of two times on the highest setting in household laundering units. That is the "test mattress sheet" the gap rule refers to.

Mattresses for non-full-size cribs

For a mattress supplied with a non-full-size crib (1241.2(b)(2)), the CFR replaces F2933 section 5.6.2 with a requirement that it meet the applicable ASTM F406 sections for Stability, Cord/Strap Length, Mattresses for Rigid sided products and Crib Side Height when tested with the product it comes with. After-market mattresses for non-full-size cribs are treated "as though the mattresses were the mattress supplied with a non-full-size crib," tested to the equivalent interior dimension of the product they are meant for. Three extra rules follow: the after-market mattress must be at least the same size as the original or larger and lie flat on the floor of the product in contact with the mattress support structure; if the original has a floor support structure, the replacement must have one at least as thick; and if the original includes storage for the instruction manual, the replacement must provide equivalent storage.

After-market mattresses for play yards

For mesh/fabric sided play yards, 1241.2(b)(3) requires that the after-market mattress and the product it is tested in meet the applicable F406 sections for Stability, Cord/Strap Length, Mattress, Height of Sides, Floor Strength and Mattress Vertical Displacement, tested with each brand and model it is intended to replace the mattress in. If the mattress is meant for the bassinet of a play yard with a bassinet attachment, it must also meet the applicable F2194 sections: Mattress Thickness for Fabric or Mesh Sided Products, Mattress dimensions, Side Height, and Bassinets with Segmented Mattresses. The CFR points to 16 CFR part 1221 for play yards and part 1218 for bassinets and cradles.

Worked example

A manufacturer measures a full-size foam mattress at 27 1/2 inches wide and 51 3/4 inches long, with a corner gap of 2.5 inches. Width 27.5 is at least 27.25, length 51.75 is at least 51.625, and gap 2.5 is not more than 3.15, so each reading meets the written value. A mattress of 27 inches by 51 1/2 inches fails on both size minimums even if the gap measurement is small. The regulation prints 690 by 1310 mm and 80.0 mm beside the inch values; choose "Millimeters" in the checker to compare against those printed metric figures directly.

Limits of this page

The checker covers only the three numbers written for full-size mattresses. It does not test thickness, firmness, flammability or any other F2933 provision, which the CFR leaves to the ASTM text. It cannot judge whether a product counts as a crib mattress or which category it falls in. Labeling, certification and testing duties come from other regulations. The CFR is current through October 29, 2026 as published in the eCFR; verify before relying on it.

Sources

Sources opened and read November 2, 2026.

• eCFR: 16 CFR part 1241, safety standard for crib mattresses (current through October 29, 2026) (read November 2, 2026)
• eCFR: 16 CFR part 1236, safety standard for infant sleep products (current through October 29, 2026) (read November 2, 2026)