What Size Mattress Fits a Convertible Crib (and the Full Bed Later)?

Two mattresses for the life of the crib, and no separate box spring to buy.

Short answer: a convertible crib uses two mattresses over its life. For the crib, toddler bed and daybed stages, use a standard US crib mattress at least 27 1/4 × 51 5/8 inches and no more than 6 inches thick. When the crib becomes a full-size bed, switch to a standard full mattress (54 × 75 inches). With Romina's conversion kits you don't need a box spring, because every kit includes two sets of wooden slats.

What size crib mattress do I need?

Every Romina crib listing carries the same rule: "Any mattress used in this crib shall be at least 27 1/4 inches by 51 5/8 inches with a thickness not exceeding 6 inches."

Why it matters:

• Minimum length and width stop gaps forming between the mattress and the crib sides, where a baby's limbs or head could get stuck.
• Maximum thickness of 6 inches keeps the top of the mattress well below the top of the rails, so the crib sides stay high enough.

A quick fit check: push the mattress firmly to one side. If you can fit more than two fingers into the gap on the other side, the mattress is too small.

Is a crib mattress included with a Romina crib?

No. Romina cribs accommodate a standard crib mattress, which is sold separately. Romina offers its own:

Shop the guide: crib mattress

• 100% Organic Dual Side Washable Kinder Mattress: $385. Dual-sided for infant through pre-K. GOLS-certified organic coconut coir core, GOTS-certified organic fabrics, zero fire retardants, no polyurethane or other poly-type materials. CPSC tested at Intertek Laboratories.

Romina explains the short spec list on purpose: "Safety should be easy to spell and simple to understand. Leaving VOCs, vinyl, polyurethane foams, polymers and flame retardants out of this mattress was intentional."

Do I need a new mattress for the toddler bed or daybed?

No. Romina's Toddler Bed and Daybed stages (24 months–4 years) use the same crib mattress, on the same platform. Only the front of the crib changes: a toddler rail goes on for the toddler bed, or the front comes off completely for the daybed. Keeping the same mattress also helps your child feel at home in the "new" bed.

What mattress size do I need for the full-size bed?

A standard full (sometimes called double) mattress: 54 × 75 inches. Romina's conversion kits and full beds are built for a standard full-size mattress.

When you convert, the crib's headboard and footboard become the bed's ends, and the conversion kit adds two full-length side rails and two sets of slats. Romina's kits describe it this way:

• Karisma Conversion Kit: "There are 2 slat rolls provided. Box spring included: no separate box spring needed, just add a standard full-size mattress."
• Cleopatra Conversion Kit: rails and slats "made of 100% solid wood, hence offering superior weight resistance. Box spring included: no separate box spring needed, just add a standard full-size mattress."
• New York and Uptown kits: "two side rails and two sets of slats which create a platform for the mattress. Box spring included: no separate box spring needed, just add a standard full-size mattress."

Shop the guide: conversion kits

• Karisma Conversion Kit: $530. Tested to support over 250 lb.
• Cleopatra Conversion Kit: $530. For models #7501 and #7502.
• New York Full-Bed Conversion Kit: $530.
• All conversion kits

Do I need a box spring for a converted Romina bed?

No. The two slat rolls create a solid platform. Box spring included: no separate box spring needed, just add a standard full-size mattress. A full bed uses two slat rolls of eight slats each. If you ever need a replacement, Romina sells a single Slats Roll for Full Bed and asks you to choose the correct bed or kit model, because slat lengths vary.

Skipping a separate box spring also keeps the bed lower, which suits younger children and smaller rooms.

What kind of mattress support does the crib itself have?

Most Romina cribs use a solid wood mattress platform with three height settings. Romina's reasoning: some supports that rely on spring tension "tend to loosen up and in turn cause the mattress to sink in the center", so it uses a wooden platform made from select hardwood instead.

One exception: the Uptown Convertible Crib (#15503) uses a metal mesh support, per Romina's replacement-part listing.

How thick should the full-size mattress be?

There's no 6-inch limit at the full-bed stage, since the crib rails are gone. But think about height. A very thick mattress on top of the platform can make the bed tall for a young child. If your child is still small at the conversion, a medium-profile mattress keeps the bed easy to climb into. Romina's Low-Profile Footboard also helps by opening up the foot of the bed.

Browse: Mattress · Conversion kits · Convertible cribs

FAQ

What size mattress fits a Romina crib?

Any standard crib mattress at least 27 1/4 × 51 5/8 inches and no more than 6 inches thick.

Does a Romina crib come with a mattress?

No. The mattress is sold separately. Romina offers the organic Kinder Mattress ($385).

What mattress do I need when the crib becomes a full-size bed?

A standard full mattress, 54 × 75 inches.

Do I need a box spring?

No. Every Romina conversion kit includes two sets of slats, so the mattress sits directly on the platform.

Can I use the same mattress for the toddler bed?

Yes. The toddler bed and daybed stages use the same crib mattress.

Related guide: When to Convert a Crib to a Toddler Bed