Mattress sizes and thicknesses for crib conversion rails
Which mattress sizes and thicknesses work with a crib conversion rail?
Westwood Design RW-TR-9309GR-ALN: Any mattress used must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. Westwood Design San Mateo Toddler Guard Rail: The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. DaVinci M12599: It requires a full-size crib mattress at least 51 5/8 in long, 27 1/4 in wide and no thicker than 6 in. dadada Baby Crib Conversion Kit (Toddler Bed Rail): The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches. The maker advises no more than one inch or two fingers of gap between the mattress edge and the crib side. Kalon (Kalon Studios) Caravan Conversion Kit (Model No. 042): Sources disagree on mattress thickness: Kalon's product page specifies 4–6 inches, while its assembly booklet specifies a minimum thickness of 6 inches (150 mm).
| Product | Why | Mattress size | Mattress thickness | Fit note |
|---|---|---|---|---|
| 1. Westwood Design RW-TR-9309GR-ALN sold by modernnursery.com | Any mattress used must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. | Any mattress used must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. manual | Any mattress used must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. manual | - |
| 2. Westwood Design San Mateo Toddler Guard Rail sold by modernnursery.com | The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. | The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. manual | The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam. manual | - |
| 3. DaVinci M12599 sold by modernnursery.com | It requires a full-size crib mattress at least 51 5/8 in long, 27 1/4 in wide and no thicker than 6 in. | It requires a full-size crib mattress at least 51 5/8 in long, 27 1/4 in wide and no thicker than 6 in. manual | It requires a full-size crib mattress at least 51 5/8 in long, 27 1/4 in wide and no thicker than 6 in. manual | - |
| 4. Dadada Baby Crib Conversion Kit (Toddler Bed Rail) sold by lovemedobaby.com | The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches. | The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches. guide | - | The maker advises no more than one inch or two fingers of gap between the mattress edge and the crib side. guide |
| 5. Kalon (Kalon Studios) Caravan Conversion Kit (Model No. 042) sold by modernnursery.com | Sources disagree on mattress thickness: Kalon's product page specifies 4–6 inches, while its assembly booklet specifies a minimum thickness of 6 inches (150 mm). | - | Sources disagree on mattress thickness: Kalon's product page specifies 4–6 inches, while its assembly booklet specifies a minimum thickness of 6 inches (150 mm). guide | - |
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Written 2026-10-29T19:28:41.272Z.
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