Double and full are the same size. There is no difference in dimensions, no hidden variation between them, and no reason to treat them as separate options when you are shopping. The two names exist because Canada and the United States historically used different words for the same mattress.
If that is all you needed, you are set. If you want to understand where the names came from, whether a double is actually right for your situation, and how it compares to the sizes around it, the rest of this guide has you covered.
The one-line answer: Double = Full. Both are 54 inches wide by 75 inches long. Any bed frame, sheet set, or mattress protector labelled "full" will fit a Canadian double mattress perfectly — and vice versa.
Why Are There Two Names?
"Double" is the traditional Canadian and British term. It came from early 20th-century marketing that positioned this size as double the width of a single — suitable for two people. At 54 inches wide that was always a generous claim, but the name stuck and remained the standard Canadian label through most of the century.
"Full" became the more common American retail term from the 1950s onward, adopted as a more neutral alternative to "double" as retailers moved away from the implication that 54 inches comfortably sleeps two adults. As American brands and retailers expanded into Canada, "full" came with them. Today both names are in active use here, which creates confusion when shoppers see them listed separately on a website and wonder whether they are actually different products. They are not. Same width, same length, same mattress.
The traditional Canadian name. Still the dominant label in most Canadian showrooms, manufacturer specifications, and custom size contexts.
The dominant American retail label, now widely used in Canada. Identical dimensions to a double. Sheets and frames labelled "full" fit a double perfectly.
Where It Sits on the Full Size Chart
The double (or full) is the third-smallest standard mattress size in Canada, sitting between the Single XL and the Queen.
| Canadian Name | Also Called | Inches | CM |
|---|---|---|---|
| Single | Twin | 38" x 75" | 97 x 191 |
| Single XL | Twin XL | 38" x 80" | 97 x 203 |
| Double | = Full | 54" x 75" | 137 x 191 |
| Queen | Queen | 60" x 80" | 152 x 203 |
| King | King | 76" x 80" | 193 x 203 |
| California King | Cal King | 72" x 84" | 183 x 213 |
One thing worth noting: the double and the single share the same 75-inch length. If you are taller than 6 feet, neither gives you enough room to stretch out fully. A queen at 80 inches long is the better choice for taller sleepers.
Is a Double the Right Size for You?
Good fit for a double
A solo adult who wants more room than a single provides without stepping up to a queen. Works well in smaller bedrooms where a queen would feel cramped or limit walking space. Also a practical choice for a teenager transitioning out of a single.
Consider stepping up if:
You are taller than 6 feet (a queen adds 5 inches of length), you share the bed with a partner (a queen gives each person 30 inches of width versus 27 on a double), or you want room to move freely throughout the night.
Two adults on a double: Technically possible, but tight. A 54-inch double gives each person about 27 inches of personal space — less than the width of a standard single. For couples who want to sleep comfortably without bumping into each other, a queen is the meaningful step up. It adds 6 inches of width and 5 inches of length for a much better night for both people.
At Dozy, our Osgoode starts at $479 and is available in Double along with other standard sizes. If your frame is a non-standard dimension — a 3/4 double at 48" x 75" is one of the most common antique frame sizes we see — we can build to your exact measurements. See our custom mattress guide for pricing and how it works.
Does It Matter Which Name You Use When Shopping?
No. Any retailer worth buying from treats double and full as interchangeable, because they are. If you search "double mattress" on a Canadian retail site and see "full" results, those are the same product. Sheets, bed frames, mattress protectors, and bases labelled "full" fit a Canadian double without any adjustment.
The exception, as with single and twin, is international shopping. A UK "double" is 135 x 190 cm — slightly narrower than the Canadian standard of 137 x 191 cm. If you are buying bedding or a frame from a UK or European retailer, check the centimetre measurements on the product page rather than trusting the size name.
The Difference Between Single and Twin Size Mattresses
Is a Mattress in a Box Worth It?