{
  "schema_version": "compare-page.v2",
  "page_id": "mattress-sizes-and-thicknesses-for-crib-conversion-rails",
  "url": "https://robotrunk.com/compare/want/mattress-sizes-and-thicknesses-for-crib-conversion-rails",
  "title": "Mattress sizes and thicknesses for crib conversion rails",
  "question": "Which mattress sizes and thicknesses work with a crib conversion rail?",
  "answer": "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.\nWestwood 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.\nDaVinci 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.\ndadada 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.\nKalon (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).",
  "kind": "crib conversion kit",
  "market": "US",
  "generated_at": "2026-10-29T19:28:41.272Z",
  "columns": [
    "Mattress size",
    "Mattress thickness",
    "Fit note"
  ],
  "notices": {
    "facts": "Every value in the table is a fact RoboTrunk checked, linked to the page it came from. A dash means no checked fact fills that cell.",
    "price": "Prices and stock change, so this page prints neither: each product name links to its RoboTrunk page, which shows them live."
  },
  "cited_facts": [
    {
      "ref": "p1.f11",
      "product": "Kalon (Kalon Studios) Caravan Conversion Kit (Model No. 042)",
      "field": "mattress size limits",
      "value": "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).",
      "stated_as": "Mattress thickness: 4”–6”",
      "source_type": "guide",
      "source_url": "https://kalonstudios.com/shop/caravan/caravan-conversion-kit/",
      "source_read_at": "2026-10-21T22:22:19.171Z"
    },
    {
      "ref": "p5.f10",
      "product": "DaVinci M12599",
      "field": "mattress requirement",
      "value": "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.",
      "stated_as": "TO AVOID DANGEROUS GAPS, ANY MATTRESS USED IN THIS BED SHALL BE A FULL-SIZE\nCRIB MATTRESS AT LEAST 51 5⁄8 IN. (131 CM) IN LENGTH, 27 1⁄4 IN. (69 CM) IN WIDTH, AND A\n                        MAX THICKNESS OF 6 IN. (15 CM).",
      "source_type": "manual",
      "source_url": "https://prime-spaces.com/wp-content/uploads/2022/10/Charlie-4-in-1-Convertible-Crib-Manual.pdf",
      "source_read_at": "2026-10-21T18:58:08.224Z"
    },
    {
      "ref": "p7.f9",
      "product": "Dadada Baby Crib Conversion Kit (Toddler Bed Rail)",
      "field": "mattress size",
      "value": "The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches.",
      "stated_as": "dadada Baby cribs and toddler beds fit a standard crib mattress size of 52.0″ x 27.75″",
      "source_type": "guide",
      "source_url": "https://dadadababy.com/pages/faqs",
      "source_read_at": "2026-10-23T15:56:22.646Z"
    },
    {
      "ref": "p7.f11",
      "product": "Dadada Baby Crib Conversion Kit (Toddler Bed Rail)",
      "field": "mattress gap",
      "value": "The maker advises no more than one inch or two fingers of gap between the mattress edge and the crib side.",
      "stated_as": "no more than two fingers width (or one inch) of space between the edge of the mattress and the crib side.",
      "source_type": "guide",
      "source_url": "https://dadadababy.com/pages/faqs",
      "source_read_at": "2026-10-23T15:56:22.646Z"
    },
    {
      "ref": "p10.f9",
      "product": "Westwood Design RW-TR-9309GR-ALN",
      "field": "mattress requirements",
      "value": "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.",
      "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.).",
      "source_type": "manual",
      "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2023/05/convertible-crib-toddler-rail.pdf",
      "source_read_at": "2026-10-23T00:12:48.708Z"
    },
    {
      "ref": "p11.f7",
      "product": "Westwood Design San Mateo Toddler Guard Rail",
      "field": "mattress size",
      "value": "The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam.",
      "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.). THE DIMENSIONS\n  OF THE MATTRESS SHOULD BE TAKEN FROM SEAM TO SEAM.",
      "source_type": "manual",
      "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2020/10/sm-toddler-rail-crib.pdf",
      "source_read_at": "2026-10-23T00:22:44.552Z"
    }
  ],
  "rows": [
    {
      "rank": 1,
      "merchant": {
        "slug": "modernnursery-com",
        "display_name": "modernnursery.com"
      },
      "product_id": "gid://shopify/Product/7217833541732",
      "name": "Westwood Design RW-TR-9309GR-ALN",
      "url": "/products/ucp/modernnursery-com/7217833541732",
      "why": "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.",
      "cells": [
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          "column": "Mattress size",
          "fact": {
            "field": "mattress requirements",
            "value": "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.",
            "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.).",
            "source_type": "manual",
            "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2023/05/convertible-crib-toddler-rail.pdf",
            "source_read_at": "2026-10-23T00:12:48.708Z"
          }
        },
        {
          "column": "Mattress thickness",
          "fact": {
            "field": "mattress requirements",
            "value": "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.",
            "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.).",
            "source_type": "manual",
            "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2023/05/convertible-crib-toddler-rail.pdf",
            "source_read_at": "2026-10-23T00:12:48.708Z"
          }
        },
        {
          "column": "Fit note",
          "fact": null
        }
      ]
    },
    {
      "rank": 2,
      "merchant": {
        "slug": "modernnursery-com",
        "display_name": "modernnursery.com"
      },
      "product_id": "gid://shopify/Product/7217833836644",
      "name": "Westwood Design San Mateo Toddler Guard Rail",
      "url": "/products/ucp/modernnursery-com/7217833836644",
      "why": "The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam.",
      "cells": [
        {
          "column": "Mattress size",
          "fact": {
            "field": "mattress size",
            "value": "The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam.",
            "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.). THE DIMENSIONS\n  OF THE MATTRESS SHOULD BE TAKEN FROM SEAM TO SEAM.",
            "source_type": "manual",
            "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2020/10/sm-toddler-rail-crib.pdf",
            "source_read_at": "2026-10-23T00:22:44.552Z"
          }
        },
        {
          "column": "Mattress thickness",
          "fact": {
            "field": "mattress size",
            "value": "The mattress must be at least 27-1/4 by 51-5/8 inches and no thicker than 6 inches, measured seam to seam.",
            "stated_as": "ANY MATTRESS USED IN THIS CRIB MUST BE AT LEAST 27-1/4 IN. (69 CM.) BY 51-5/8\n  IN. (131 CM.), WITH A THICKNESS NOT EXCEEDING 6 IN. (15 CM.). THE DIMENSIONS\n  OF THE MATTRESS SHOULD BE TAKEN FROM SEAM TO SEAM.",
            "source_type": "manual",
            "source_url": "https://www.westwoodbaby.com/wp-content/uploads/2020/10/sm-toddler-rail-crib.pdf",
            "source_read_at": "2026-10-23T00:22:44.552Z"
          }
        },
        {
          "column": "Fit note",
          "fact": null
        }
      ]
    },
    {
      "rank": 3,
      "merchant": {
        "slug": "modernnursery-com",
        "display_name": "modernnursery.com"
      },
      "product_id": "gid://shopify/Product/7128530649188",
      "name": "DaVinci M12599",
      "url": "/products/ucp/modernnursery-com/7128530649188",
      "why": "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.",
      "cells": [
        {
          "column": "Mattress size",
          "fact": {
            "field": "mattress requirement",
            "value": "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.",
            "stated_as": "TO AVOID DANGEROUS GAPS, ANY MATTRESS USED IN THIS BED SHALL BE A FULL-SIZE\nCRIB MATTRESS AT LEAST 51 5⁄8 IN. (131 CM) IN LENGTH, 27 1⁄4 IN. (69 CM) IN WIDTH, AND A\n                        MAX THICKNESS OF 6 IN. (15 CM).",
            "source_type": "manual",
            "source_url": "https://prime-spaces.com/wp-content/uploads/2022/10/Charlie-4-in-1-Convertible-Crib-Manual.pdf",
            "source_read_at": "2026-10-21T18:58:08.224Z"
          }
        },
        {
          "column": "Mattress thickness",
          "fact": {
            "field": "mattress requirement",
            "value": "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.",
            "stated_as": "TO AVOID DANGEROUS GAPS, ANY MATTRESS USED IN THIS BED SHALL BE A FULL-SIZE\nCRIB MATTRESS AT LEAST 51 5⁄8 IN. (131 CM) IN LENGTH, 27 1⁄4 IN. (69 CM) IN WIDTH, AND A\n                        MAX THICKNESS OF 6 IN. (15 CM).",
            "source_type": "manual",
            "source_url": "https://prime-spaces.com/wp-content/uploads/2022/10/Charlie-4-in-1-Convertible-Crib-Manual.pdf",
            "source_read_at": "2026-10-21T18:58:08.224Z"
          }
        },
        {
          "column": "Fit note",
          "fact": null
        }
      ]
    },
    {
      "rank": 4,
      "merchant": {
        "slug": "lovemedobaby-com",
        "display_name": "lovemedobaby.com"
      },
      "product_id": "gid://shopify/Product/7525176017030",
      "name": "Dadada Baby Crib Conversion Kit (Toddler Bed Rail)",
      "url": "/products/ucp/lovemedobaby-com/7525176017030",
      "why": "The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches.",
      "cells": [
        {
          "column": "Mattress size",
          "fact": {
            "field": "mattress size",
            "value": "The maker says its cribs and toddler beds fit a standard crib mattress of 52.0 x 27.75 inches.",
            "stated_as": "dadada Baby cribs and toddler beds fit a standard crib mattress size of 52.0″ x 27.75″",
            "source_type": "guide",
            "source_url": "https://dadadababy.com/pages/faqs",
            "source_read_at": "2026-10-23T15:56:22.646Z"
          }
        },
        {
          "column": "Mattress thickness",
          "fact": null
        },
        {
          "column": "Fit note",
          "fact": {
            "field": "mattress gap",
            "value": "The maker advises no more than one inch or two fingers of gap between the mattress edge and the crib side.",
            "stated_as": "no more than two fingers width (or one inch) of space between the edge of the mattress and the crib side.",
            "source_type": "guide",
            "source_url": "https://dadadababy.com/pages/faqs",
            "source_read_at": "2026-10-23T15:56:22.646Z"
          }
        }
      ]
    },
    {
      "rank": 5,
      "merchant": {
        "slug": "modernnursery-com",
        "display_name": "modernnursery.com"
      },
      "product_id": "gid://shopify/Product/4798889951332",
      "name": "Kalon (Kalon Studios) Caravan Conversion Kit (Model No. 042)",
      "url": "/products/ucp/modernnursery-com/4798889951332",
      "why": "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).",
      "cells": [
        {
          "column": "Mattress size",
          "fact": null
        },
        {
          "column": "Mattress thickness",
          "fact": {
            "field": "mattress size limits",
            "value": "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).",
            "stated_as": "Mattress thickness: 4”–6”",
            "source_type": "guide",
            "source_url": "https://kalonstudios.com/shop/caravan/caravan-conversion-kit/",
            "source_read_at": "2026-10-21T22:22:19.171Z"
          }
        },
        {
          "column": "Fit note",
          "fact": null
        }
      ]
    }
  ]
}