Standard Mattress Crib Size in Canada (2026)

Quick Answer: A standard crib mattress in Canada measures 69.2 cm by 131.1 cm (27 1/4 by 51 5/8 inches), the US federal minimum that North American makers build to. Canada's crib regulations (SOR/2016-152) cap thickness at 150 mm and allow no gap over 30 mm with the mattress pushed against any side.

16 min read · Updated October 9, 2026

A standard crib mattress is the full-size mattress made for a full-size crib. It is at least 69.2 cm wide and 131.1 cm long (27 1/4 by 51 5/8 inches), and no more than 15 cm (just under 6 inches) thick in Canada. The width and length come from the US crib mattress rule, 16 CFR 1241, which says a full-size crib mattress "shall measure at least 27 1/4 in. (690 mm) wide and 51 5/8 in. (1310 mm) long." Canada's Cribs, Cradles and Bassinets Regulations (SOR/2016-152) set no length or width. They regulate thickness and fit. Crib mattress dimensions only really vary once you step outside the full-size crib, into mini cribs, portable cribs and Pack 'n Plays. That is where most of the confusion in the baby aisle starts.

Mattress Miracle is a family-owned mattress store in Brantford, Ontario, run by the Grose family since 1997. We do not sell crib mattresses. Parents ask us crib-size questions constantly anyway, usually because a grandparent passed down a crib or a replacement mattress did not fit. So Mattress Miracle put the real numbers and the Canadian safety rules in one place. The bed we do fit is the one that comes after the crib: our twin mattresses for a child's first big bed.

A full-size crib is built around that mattress. Under the ASTM crib standard that US law adopts, the inside of the crib measures 28 by 52 3/8 inches (about 71 by 133 cm), plus or minus 5/8 inch. That figure comes from Sealy Baby's crib mattress fit guide. The mattress is slightly smaller so it can go in and out.

How Firm Should a Crib Mattress Be?

A crib mattress should be firm and flat, with a tightly fitted sheet and nothing else on it. That is the standard in the Joint Statement on Safe Sleep. Four bodies wrote it: the Public Health Agency of Canada, the Canadian Paediatric Society, Health Canada and Baby's Breath Canada. A safe infant sleep surface, it says, "has a firm, flat mattress with a tightly fitted sheet." It also has "no gaps between the mattress and sides, where the infant could become trapped." Health Canada's crib safety page warns that "a soft mattress can suffocate your baby." The Canadian Paediatric Society adds the other half of the rule: "Always place your baby on their back to sleep, for every sleep."

The American Academy of Pediatrics gives the plain test in its parent's guide to safe sleep: a firm surface "shouldn't indent when your baby is lying on it." The warning label Canada requires on every crib says "Do not place pillows, comforters or soft mattresses in this crib." That is why a soft adult memory foam mattress is not appropriate for an infant crib, even if it fits the frame.

This article is general information, not medical advice. Follow Health Canada's safe sleep tips, and ask your doctor or paediatrician about your own baby's sleep.

All Crib Mattress Sizes at a Glance

Our Canadian mattress size chart covers adult beds; crib mattress sizes fall into a handful of types of their own. Only the full-size crib mattress has a federal minimum size behind it. The thickness limits for cribs, cradles and bassinets are Canadian law.

Mattress type Size (cm) Size (inches) Thickness rule in Canada Where the numbers come from
Standard full-size crib mattress 69.2 x 131.1 minimum 27 1/4 x 51 5/8 minimum 15 cm (just under 6 in) maximum Size: US 16 CFR 1241. Thickness: SOR/2016-152, s. 22
Inside of a full-size crib about 71 x 133 28 x 52 3/8, plus or minus 5/8 Not applicable ASTM crib standard, per Sealy Baby
Mini crib mattress about 61 x 96.5 about 24 x 38 15 cm (just under 6 in) maximum, because a mini crib is a crib in law Size: Sleep Foundation. Thickness: SOR/2016-152
Cradle or bassinet mattress Varies by model Varies by model 3.8 cm (1 1/2 in) maximum SOR/2016-152, s. 22
Pack 'n Play or playpen pad Varies by model Varies by model Use only the pad it came with; never add a mattress Health Canada
Toddler bed (takes a crib mattress) 69.2 x 131.1 27 1/4 x 51 5/8 Same crib mattress Size: US 16 CFR 1241 (same mattress). Fit: Health Canada, Sleep Time guide
Twin (first "big kid" bed) 96.5 x 190.5 38 x 75 No legal limit Better Sleep Council

Pack 'n Play and playpen pads are thin by design, and the pad that comes with the unit is the only mattress to use in it. Health Canada does not recommend a playpen for unsupervised sleep, and its Safe sleep on the go page says not to "add an extra mattress or padding to the playpen."

What Is the Standard Crib Mattress Size in Canada?

Standard crib mattress dimensions chart for Canadian cribs - Mattress Miracle Brantford

The standard crib mattress size in Canada is 69.2 cm by 131.1 cm (27 1/4 by 51 5/8 inches) at minimum, and no more than 15 cm (just under 6 inches) thick. Those limits come from two different laws.

The size is American. The US crib mattress standard sets the minimum at 690 mm by 1310 mm, and makers selling across North America build to it. Canada's Cribs, Cradles and Bassinets Regulations set the fit instead. Section 22 says a mattress supplied with a crib "must be not more than 150 mm thick." Pushed firmly against any side, it must not leave "a gap of more than 30 mm between the mattress and any part of any other side."

A crib sold without a mattress carries the same rule on its section 55 warning label. It says to use a mattress "no thicker than 15 cm" that leaves no gap "of more than 3 cm." Section 51 also requires every crib to show "the dimensions recommended by the manufacturer for the mattress." That label beats any size chart, including ours.

Good news: North American makers build to the same minimum. So a mattress labelled "standard crib size" or "full-size crib mattress" fits a full-size crib from another brand in most cases. Brands do not have to match. The gap check in your own crib still has the final say.

Thickness varies within the standard. Canada's limit is 15 cm, and a true 6-inch mattress measures 15.2 cm, so check the thickness in centimetres. Pottery Barn Kids' guide puts coil crib mattresses at 5 to 6 inches and foam at 4 to 6. Firmness matters more than thickness: choosing a thicker mattress purely for plushness works against safe-sleep guidance.

Why the Exact Size Matters

The 3 cm (30 mm) maximum gap is not arbitrary. A mattress that is too small leaves a space at the side where a baby can become trapped, the hazard the federal safe sleep statement names. The US rule tests a crib corner instead, where the gap "shall not exceed 3.15 in. (80.0 mm)." In a Canadian crib, the 3 cm side gap is the number to check.

How Big Is a Standard Crib? Crib Bed Dimensions

A standard full-size crib measures 28 inches by 52 3/8 inches inside (about 71 by 133 cm), with 5/8 inch of tolerance either way. That is the ASTM crib standard as Sealy Baby's crib fit guide summarizes it. The outside varies by model, because rails and posts add width and length. Plan the room with the maker's outside size and buy the mattress by the inside size.

The gap between mattress and crib is built in. A 69.2 cm mattress in a 71.1 cm crib leaves 1.9 cm across the width. A 131.1 cm mattress in a 133 cm crib leaves 1.9 cm along the length, inside Health Canada's 3 cm limit. The tolerance is where trouble starts. The US mattress rule sets its test corner at 28 5/8 by 53 inches (727 by 1346 mm), the largest a full-size crib can be. A minimum-size mattress pushed to one side of a crib that big would leave about 3.7 cm on the other side (727 minus 690 mm). That is over the Canadian limit, and it is why you measure.

The crib itself has measurements to check too. Health Canada's cribs, cradles and bassinets page says slats should be no more than 6 cm apart. Corner posts should be no higher than 1.5 mm above the top of the sides. The crib's own warning label sets its limit: "Do not use this crib for a child who can climb out of it or who is taller than 90 cm."

Mini Crib Mattress Size

A mini crib mattress measures about 61 cm by 96.5 cm (24 by 38 inches), the typical mini crib size in the Sleep Foundation's crib mattress size guide. Mini cribs suit compact nurseries, apartments, or a second sleep space such as a grandparent's home.

Important: mini crib mattresses and standard crib mattresses are not interchangeable. A standard mattress will not fit a mini crib, and a mini mattress used in a standard crib will leave dangerous gaps on all sides.

The same Canadian rules apply to a mini crib. SOR/2016-152's definition of a crib includes a size test: "a sleeping surface area that is greater than 5 500 cm2." A typical 61 by 96.5 cm mini crib has about 5,890 cm2, so its mattress falls under the 15 cm thickness limit and the 30 mm gap rule. Mini crib mattress dimensions are less standardized than full-size. Always check your mini crib's interior measurements and the mattress size printed on it before buying a replacement mattress. Mattress Miracle does not stock mini crib mattresses, so buy from the crib's maker or a baby retailer that lists the exact size. Our mini crib mattress size and safety guide walks through the differences in more detail.

Pack 'n Play and Portable Crib Mattress Size

Portable cribs and Pack 'n Plays come with their own mattress pads, and this is the only mattress you should use with them. These pads are intentionally thin for safety reasons. A thicker mattress can create suffocation risk in a portable enclosure.

Health Canada goes further on where babies sleep. "In Canada, playpens are not recommended for unsupervised sleep because they're not as durable and safe as cribs," its travel safety page says. A bassinet attachment made for the playpen is the exception. Health Canada calls it a safe option "until they can roll over or reach the attachment's weight limit, whichever comes first." The federal Joint Statement's playpen guidance adds that playpens "are not regulated for infant sleep in Canada."

Do not add extra padding, toppers, or aftermarket mattresses to a portable crib. The product is safety-tested with its included pad only. US stores sell after-market play yard mattresses. The Canadian Paediatric Society's safe sleep handout, Health Canada and the Public Health Agency of Canada all say never to add an extra mattress or padding to a playpen.

Toddler Mattress Size

Most toddler beds use the same mattress dimensions as standard cribs: 69.2 cm x 131.1 cm. If your crib converts to a toddler bed, you can continue using the same mattress. Health Canada's Is Your Child Safe? Sleep Time guide puts it this way: "Many crib mattresses fit toddler beds." Know your crib mattress dimensions before you shop and make sure the two are compatible. The same guide says toddler beds are meant to be used until a child turns about five. Openings in the guardrails should be less than 8.4 cm (3.3 in) apart.

The difference is firmness. Some dual-sided crib mattresses have a firmer infant side and a softer toddler side. Health Canada's mattress-buying checklist says to make sure the firm side faces up. Keep that firm infant side up for any baby under one year. The Sleep Foundation describes flipping to the softer side as a child approaches the toddler years. Follow the maker's label, and ask your doctor if you are unsure when to switch.

A crib-size floor bed is a low frame built to take a standard crib mattress, which is why "crib size bed" searches turn up so many of them. Health Canada names a crib, cradle or bassinet as the safest place for a baby to sleep, so a floor bed is never for a baby under 12 months. Treat it as a toddler bed for a child who has reached the crib limit (taller than 90 cm or climbing out), and set the room up first with our Montessori floor bed setup guide.

Is a Crib Mattress the Same Size as a Twin?

A crib mattress is much smaller than a twin. A twin mattress is 96.5 cm by 190.5 cm (38 by 75 inches), the size the Better Sleep Council lists. That makes it about 27 cm wider and 59 cm longer than a 69.2 by 131.1 cm crib mattress. Sheets, protectors and frames do not cross over between the two, so a new twin needs twin bed sheets too. Our twin mattress size guide for Canada covers the 38-versus-39-inch question that comes up on spec sheets.

The move usually comes after the toddler bed. Health Canada's rule is to move a child "from a crib to a junior bed" once they can climb out or are taller than 90 cm, "whichever comes first." The American Academy of Pediatrics uses 35 inches (89 cm). Our crib to toddler bed transition guide covers the readiness signs and room childproofing.

This is where Mattress Miracle can help directly. The twin page on our site lists 44 mattresses today, from $86 for a 5-inch foam twin on sale (regular $105). For kids, our advisors recommend the Restonit Premium Foam 7-inch twin at $173 and the C.J. Mulholland Series 5000 bamboo twin at $305. The Series 6000 twin is $362, and seven of the eight models in our Restonic range come in twin, from $1,079. Eligible mattresses carry the Mattress Miracle 60-Night Comfort Guarantee, with one exchange and no exchange fee.

If the twin is going on a bunk, Health Canada's rule is "No children under 6 years old on the top bunk at any time." Our bunk bed collection starts at $400 for a children's twin-over-twin.

Which Crib Size Do You Actually Need?

If the table above feels like a lot, here is the short decision path most Brantford parents end up following:

Pick by your situation, not by the biggest number

  • You have a standard full-size crib (most common): buy a standard crib mattress, at least 69.2 cm x 131.1 cm and no more than 15 cm thick. A "standard" or "full-size" crib mattress fits in most cases; confirm with the gap check.
  • You have a small nursery, condo, or a second crib at grandma's: a mini crib plus a mini crib mattress (about 61 cm x 96.5 cm) saves floor space. Measure first, because mini sizes are less consistent.
  • You travel: Health Canada recommends a crib, cradle or bassinet, or a playpen's bassinet attachment until your baby can roll over. Health Canada does not recommend a playpen itself for unsupervised sleep. If you must use one for a night away, follow Health Canada's playpen travel rules: set it on the floor in the room where you sleep and use only its own thin pad. Never add a mattress.
  • Your crib converts to a toddler bed: keep the same standard mattress, firm side up, as Health Canada advises. Switch to a softer toddler side only after your child's first birthday, and only when the maker's label allows it.
  • Your child is climbing out or taller than 90 cm: it is time for a junior bed, and later a twin. The twin is the first bed Mattress Miracle can actually fit you for, and our twin mattresses in the Brantford showroom start there.

How to Measure a Crib for a Mattress

To measure a crib for a mattress, measure the inside of the crib, then check the gap with the mattress in place. The inside measurements also tell you whether the crib is standard or mini.

Measuring Steps

  1. Remove any existing mattress from the crib.
  2. Measure the interior width at the widest point (side to side).
  3. Measure the interior length at the longest point (end to end).
  4. If your measurements are approximately 71 cm x 133 cm, you have a standard crib. Buy a standard crib mattress.
  5. If your measurements are a little over 61 cm x 96.5 cm, you have a mini crib. Buy the mini crib mattress size printed on the crib.
  6. If your measurements do not match either size, you may have a specialty or vintage crib. Contact the manufacturer for mattress specifications.
  7. Put the mattress in, push it firmly against one side, and measure the gap on the opposite side. Health Canada's 3 cm limit applies. Repeat for each side and end.
  8. Measure the thickness: no more than 15 cm for a crib mattress.
  9. Set the mattress support for your baby's stage. Health Canada says to move it to its lowest level when your baby can sit upright or push up on hands and knees. Our guide to lowering the crib mattress lines the settings up with milestones.

Two adult fingers is the quick version of the gap check. If more than two fingers fit at the sides or ends, says the American Academy of Pediatrics' HealthyChildren.org crib checklist, "the crib and mattress combination should not be used." A ruler settles it against the Canadian 3 cm. Our step-by-step crib mattress gap test shows where to check.

"Parents sometimes inherit cribs from family, which is lovely, but it can cause real trouble. Older cribs may not meet current safety standards, and finding a properly fitting mattress for an odd-sized frame can be difficult or impossible. If your crib is more than ten years old, I would check whether it meets current Health Canada regulations before spending money on a mattress for it."

Dorothy Balicki, Mattress Miracle

A Note on Vintage and Antique Cribs in Brantford Homes

Brantford has many families with cribs passed down through generations. Health Canada says every crib sold or given away in Canada, new or used, must meet current safety regulations. "Cribs made before September 1986 should not be used," its crib page says. And "as of December 29, 2016, it's illegal to sell, import, manufacture or advertise traditional drop-side cribs in Canada." The Public Health Agency of Canada's Safe Sleep for Your Baby brochure adds that Health Canada recommends a crib no more than 10 years old. Read the crib's date label and search the Health Canada recalls and safety alerts database before you use it. We have had Brantford grandparents come in genuinely surprised that the crib they kept for 20 years is no longer considered safe. You are not alone if that is news.

Find Your Child's First "Big Kid" Mattress at Mattress Miracle

We do not sell crib mattresses, but when your little one is ready to move up to a twin, we are the family-owned shop on West Street to help. Mattress Miracle has been fitting Brantford families since 1997, and our team does not work on commission, so you get no-pressure advice. Browse our twin mattress collection with today's prices, or read how our 60-Night Comfort Guarantee works before you visit.

441 1/2 West Street, Brantford, Ontario

Call 519-770-0001

Frequently Asked Questions

What is the standard crib mattress size in centimetres?

A standard crib mattress measures at least 69.2 cm wide by 131.1 cm long, the US federal minimum of 27 1/4 by 51 5/8 inches. In Canada it can be no more than 15 cm thick. Canada's own regulation, SOR/2016-152, sets the thickness and the 3 cm gap limit rather than the length and width.

Will any standard crib mattress fit any standard crib?

Usually, when both are labelled "standard" or "full-size," because makers build to the same sizes. A crib's inside can run 5/8 inch over nominal. Push the mattress against one side and check the other: more than 3 cm, or more than two adult fingers, means the fit is too loose.

How big is the gap allowed between a crib mattress and the frame?

SOR/2016-152 allows no more than 30 mm (3 cm, about 1 3/16 inches) between the mattress and any other side when the mattress is pushed firmly against one side. Two adult fingers is the American Academy of Pediatrics' quick check, and our two-finger gap test walkthrough shows each spot to check. A ruler is the real test.

When should my child move from a crib mattress to a twin?

Health Canada says to move from a crib to a junior bed when your child can climb out or is taller than 90 cm, whichever comes first. A toddler bed keeps the crib mattress until about age five. A twin (96.5 cm x 190.5 cm) usually comes next, and Mattress Miracle carries most of the Restonic mattress range in twin size in Brantford.

What is a crib size sheet?

A crib size sheet is a fitted sheet cut for a standard 69.2 by 131.1 cm crib mattress. Health Canada's Sleep Time guide says to "use a fitted bottom sheet made specifically for a crib mattress of the same size." The crib should hold nothing but the mattress and that sheet. Mini crib and playpen sheets are different sizes.

Is a 3 year old too big for a crib?

Height and climbing decide it. Health Canada's limit is 90 cm tall or able to climb out, whichever comes first, and the American Academy of Pediatrics uses 35 inches (89 cm). A three-year-old under 90 cm who stays put is still within the Canadian rule. Our guide to the signs a child is ready to leave the crib covers what else to watch for.

Will a toddler bed set fit a crib mattress?

Usually, yes. Health Canada notes that "many crib mattresses fit toddler beds" and says to confirm the two are compatible before you buy. Toddler bedding is cut for the same 69.2 by 131.1 cm mattress; check for gaps at the guardrails, headboard and footboard.

What does 3 in 1 crib mean?

A 3-in-1 crib is a convertible crib, and the number counts the beds it turns into. Pottery Barn Kids' toddler mattress guide notes that convertible cribs become toddler beds on the same mattress. Some also convert to a daybed or a twin bed, and the twin mode needs a twin mattress.

Why should a crib be 3 feet from a window?

Canada's rules set no distance in feet. The crib warning reads: "Do not place this crib near a window or patio door where a child could reach the cord of a blind or curtain and be strangled." Place the crib where a standing child cannot reach any cord.

How often should you replace a crib mattress?

Health Canada gives no set number of years. Its used-crib checklist says to replace a mattress that is worn out or soft. A soft mattress can suffocate a baby, and a worn one can have sharp springs and loose threads. Check it before every new baby: it should not sag or hold a dent.

Can you put a mattress topper on a crib mattress?

No. The Canadian Paediatric Society's safe sleep advice lists mattress toppers among the soft items to keep out of a baby's sleep space. Health Canada says never to add padding or an extra mattress to a playpen. Ask your doctor if your baby has a medical reason for a special sleep surface.

Sources

  1. Government of Canada. Cribs, Cradles and Bassinets Regulations (SOR/2016-152), sections 2, 22, 51, 53 and 55. laws-lois.justice.gc.ca (accessed October 9, 2026).
  2. Health Canada. Cribs, cradles and bassinets (published 2024-11-20). canada.ca.
  3. Health Canada. Safe sleep on the go (published 2024-11-20). canada.ca.
  4. Health Canada. Is Your Child Safe? Sleep Time. canada.ca.
  5. Health Canada. Bunk beds and loft beds. canada.ca.
  6. Public Health Agency of Canada, Canadian Paediatric Society, Health Canada and Baby's Breath Canada. Joint Statement on Safe Sleep: Reducing Sudden Infant Deaths in Canada. canada.ca.
  7. Public Health Agency of Canada. Safe Sleep for Your Baby (brochure). canada.ca.
  8. Canadian Paediatric Society. Safe sleep for babies (last updated October 2021). caringforkids.cps.ca.
  9. U.S. Consumer Product Safety Commission. 16 CFR Part 1241, Safety Standard for Crib Mattresses. ecfr.gov.
  10. American Academy of Pediatrics, HealthyChildren.org. Make Baby's Room Safe: Parent Checklist; and A Parent's Guide to Safe Sleep. healthychildren.org.
  11. Sealy Baby. Crib Mattress Fit and Dimensions. sealybaby.com.
  12. Better Sleep Council. Mattress Sizes. bettersleep.org.
  13. Sleep Foundation. What Size Is a Crib Mattress? (updated July 16, 2025). sleepfoundation.org.
  14. Pottery Barn Kids. Toddler Mattress Size Guide and When to Make the Switch. potterybarnkids.com.

This article is for informational purposes only. Always verify product safety compliance and follow Health Canada's safe sleep guidelines.

Visit Our Brantford Showroom

We are located at 441½ West Street in Brantford, in the city since 1997 and on West Street since 2010. Parking is free, right at the store. Our team does not work on commission, so you get advice based on your needs.

Mattress Miracle , 441½ West Street, Brantford, ON · (519) 770-0001

Hours: Monday to Wednesday 10am to 6pm, Thursday to Friday 10am to 7pm, Saturday 10am to 5pm, Sunday 12pm to 4pm.

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Written by , Content Specialist at Mattress Miracle. Topical expertise sourced from Brad Grose (founder, 1997), Talia Grose (sleep specialist), and Dorothy Balicki (40+ years industry).

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