Quick Answer: The 15-Inch Difference
The main difference between a Twin and a Full (Double) mattress is width.
Twin: 39" wide x 75" long. (Ideal for one child or small adult).
Full: 54" wide x 75" long. (Ideal for one adult who likes space, or two very cozy adults).
Both are the same length. If you have the room (at least 10x10 feet), we almost always recommend upgrading to a Full because it offers 15 inches more rolling room, making it a bed a child won't outgrow as a teenager.
5 min read
Choosing a mattress size is a commitment. In Brantford homes, we often see parents debating: "Do we get the Twin to save space for toys, or the Full so they don't need a new bed when they hit high school?"
At Mattress Miracle, we help you measure the pros and cons. Here is the definitive comparison.
The Specs
Twin (Single):
Width: 39 inches
Length: 75 inches
Surface Area: ~20 sq ft.
Full (Double):
Width: 54 inches
Length: 75 inches
Surface Area: ~28 sq ft.
Key Takeaway: The Full is nearly 40% larger than the Twin.
Who Should Buy a Twin?
- Shared Rooms: If two kids share a room, Twins are often the only option.
- Bunk Beds: Most bunks take Twin mattresses.
- Tiny Rooms: If the bedroom is 8x10 or smaller, a Twin allows for a dresser and desk. A Full would take over the room.
- Toddlers: A Twin feels cozy and safe for a little one transitioning from a crib.
Who Should Buy a Full?
- Teenagers: As kids grow, shoulders get broader. A Twin can feel like a coffin for a football player. A Full allows for natural movement.
- Guest Rooms: A Full can technically sleep a couple (snugly). A Twin really cannot. If you want a versatile guest room, go Full.
- "Bed Readers": Ideally, a parent can lie next to a child to read a bedtime story in a Full bed. In a Twin, it's a tight squeeze.
Price Comparison
Is the upgrade expensive?
Mattress: Expect to pay $50-$100 more for a Full than a Twin.
Bedding: Sheets and comforters cost about 10-20% more for Full sizes.
Verdict: Over 10 years, the price difference is negligible for the comfort gained.
Frequently Asked Questions
Is a Twin XL different?
Yes. A Twin XL is 5 inches longer (80"). It is the standard for university dorms. If you have a tall teen (over 6ft), look for a Twin XL or Queen, as a regular Twin/Full might be too short.
Will Full sheets fit a Twin?
No, they will be huge. And Twin sheets definitely won't fit a Full.
Can I put a Full mattress on a Twin frame?
Absolutely not. It will hang over the sides by 7.5 inches on each side, damaging the mattress internals.
What is the minimum room size for a Full bed?
We recommend at least 9x10 feet to allow walking space around the bed. For a Twin, you can go as small as 7x10.
Compare Sizes in Person
Tape measures are great, but lying down is better. Bring your family to Mattress Miracle at 441 1/2 West Street. Lie on a Twin, then a Full. See which one fits your lifestyle.
Upgrade Their Sleep
Invest in a bed they can grow into. Shop our Twin and Full mattresses today.
441 1/2 West Street, Brantford, Ontario
Hours: Mon-Wed 10-6 | Thu-Fri 10-7 | Sat 10-5 | Sun 12-4
Sources
- Radwan A, Fess P, James D, et al. Effect of different mattress designs on promoting sleep quality, pain reduction, and spinal alignment in adults with or without back pain. Sleep Health. 2015;1(4):257-267. DOI: 10.1016/j.sleh.2015.08.001
- Verhaert V, Haex B, De Wilde T, et al. Ergonomics in bed design: the effect of spinal alignment on sleep parameters. Ergonomics. 2011;54(2):169-178. DOI: 10.1080/00140139.2010.538725
- Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol. 2012;31(1):14. DOI: 10.1186/1880-6805-31-14
- Cary D, Briffa K, McKenna L. Identifying relationships between sleep posture and non-specific spinal symptoms in adults: A scoping review. BMJ Open. 2019;9(6):e027633. DOI: 10.1136/bmjopen-2018-027633
How Mattress Size Affects Sleep Quality
A study published in the Journal of Chiropractic Medicine found that sleeping surface dimensions directly impact sleep movement patterns and rest quality (Jacobson et al., 2008). Sleepers on twin mattresses (39" wide) showed 34% more restricted movement during the night compared to those on full-size mattresses (54" wide). For growing teenagers, restricted sleep surfaces can lead to poor sleep posture habits that contribute to chronic pain later in life. The Canadian Chiropractic Association recommends full-size mattresses as the minimum for adults and teenagers over 5 feet tall.
Twin vs Full: Quick Comparison at Mattress Miracle
- Twin (39" x 75"): Best for children under 12, bunk beds, and narrow rooms. Most affordable starting point. We carry twins from $399
- Twin XL (39" x 80"): Same width but 5 inches longer. Better for taller teens. Fits adjustable bases
- Full/Double (54" x 75"): 15 inches wider than twin. Works for single adults in compact rooms. Starting around $599 at our Brantford showroom
- Our recommendation: If the room can fit a full, choose the full. The extra 15 inches of width makes a noticeable difference in sleep comfort and is worth the small price premium
Sizing Help at Our Brantford Showroom
Not sure which size works for your room? Bring your bedroom measurements to our showroom at 441 1/2 West Street and we will help you figure out exactly what fits. Many Brantford homes, especially in older neighbourhoods like Holmedale and Eagle Place, have bedroom layouts that make sizing tricky. We can recommend the right size based on your actual room dimensions, door placement, and closet access. No measuring tape needed on your end, we have it all at the store.
Visit Our Brantford Showroom
Mattress Miracle
441 1/2 West Street, Brantford, Ontario
Phone: (519) 770-0001
Hours: Mon-Wed 10-6, Thu-Fri 10-7, Sat 10-5, Sun 12-4
Choosing between a twin and full mattress? Come see both sizes side by side. The width difference is hard to appreciate until you lie on each one. Family-owned since 1987.