Sources
- Jacobson, B. H. et al. (2008). "Grouped comparisons of sleep quality for new and personal bedding systems." Applied Ergonomics, 39(2), 247-254. PubMed 17662962.
- Radwan, A. et al. (2015). "Effect of different mattress designs on promoting sleep quality, pain reduction, and spinal alignment." Sleep Health, 1(4), 257-267. PubMed 29073401.
- Kovacs, F. M. et al. (2003). "Effect of firmness of mattress on chronic non-specific low-back pain." The Lancet, 362(9396), 1599-1604. PubMed 14630439.
Quick Answer: Costco carries basic king box springs in limited availability and styles, typically sold online rather than in-warehouse. If you need a king box spring now and want to see it before buying, local mattress retailers like Mattress Miracle in Brantford typically carry a wider selection with same-day availability and no membership requirement.
In This Guide
Reading Time: 6 minutes
Looking for a king box spring can lead shoppers to Costco as a first stop given the brand trust and price expectations. This guide gives you the information you need to evaluate whether Costco's offering meets your needs or whether a dedicated mattress store is a better option for this particular purchase.
King Box Spring Dimensions
A standard king box spring has specific dimensions that must match your king mattress and bed frame:
| Specification | Measurement |
|---|---|
| Standard king width | 193 cm (76 inches) |
| Standard king length | 203 cm (80 inches) |
| Standard profile height | 23 cm (9 inches) |
| Low-profile height | 14 cm (5.5 inches) |
| Split king: each piece | 99 x 203 cm (39 x 80 inches) |
When buying a king box spring, measure the interior dimensions of your bed frame to ensure the box spring fits inside without gaps. A loose-fitting box spring can shift under the mattress, creating uneven support and premature wear.
Split King vs. One-Piece King
Moving a King Box Spring: A standard one-piece king box spring (193 x 203 cm) is the largest furniture piece most people ever try to move through a house. It will not fit around a standard Canadian residential staircase landing. If your bedroom is on an upper floor, a split king (two twin XL pieces) is almost always necessary. Measure the width of your staircase landing before ordering a one-piece king.
| Feature | One-Piece King | Split King (2x Twin XL) |
|---|---|---|
| Manoeuvrability | Difficult through stairs, corners | Easy through tight spaces |
| Feel uniformity | Seamless surface | Small gap at centre |
| Cost | Usually lower | Sometimes slightly higher |
| Best for | Ground floor, wide stairways | Upper floors, narrow hallways |
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What to Check Before Buying
Whether buying from Costco, another retailer, or a local store, verify these before committing to a king box spring:
- Weight capacity: King box springs support two adults. Look for a minimum weight rating of 500 kg (1,100 lbs) for the spring itself.
- Frame material: Wood-framed springs with steel coils outperform particle board frames significantly over 5 to 10 years of use.
- Slat spacing: For king sizes where the slats must span the full width, narrower slat spacing (under 7.5 cm / 3 inches) provides better support without sagging.
- Mattress compatibility: Confirm your mattress manufacturer does not specify restrictions on box spring type. Some memory foam and latex mattress warranties are voided by traditional coil box springs.
- Return policy: A king box spring is difficult to return. Confirm the return process before purchasing, especially online.
Alternatives to a Box Spring
| Alternative | Best For | Cost (King) |
|---|---|---|
| Platform bed with slats | Foam and latex mattresses | $300 to $800 |
| Low-profile box spring | Modern frames needing box spring look | $250 to $450 |
| Adjustable base (king) | Couples with different sleep preferences | $1,200 to $3,000+ |
| Bunky board | Very low profiles, platform beds | $150 to $300 |
Mattress Miracle Insight: Many king mattress buyers who come in looking for a box spring leave with a different recommendation after we understand their mattress type. If you have a memory foam king mattress, a traditional box spring is almost never the right pairing. We will help you find what actually works for your specific mattress at our Brantford showroom, whether that is a box spring, platform base, or something else entirely.
Brantford Option: Mattress Miracle carries king box springs and king platform foundations at our West Street location. Unlike warehouse stores, you can see and feel the foundation before purchasing. We also offer same-day pickup for in-stock items and local delivery, which is particularly useful for a large king-size piece.
Shop: King Mattresses at Mattress Miracle
Find Your Perfect Mattress at Mattress Miracle
We are a family-owned mattress store in Brantford, helping our community sleep better since 1997. Come try mattresses in person and get honest, no-pressure advice.
441 1/2 West Street, Brantford, Ontario
Call 519-770-0001Frequently Asked Questions
Does Costco sell king box springs?
Costco's box spring selection varies by location and season. They sometimes carry basic king box springs online or in-warehouse, typically in limited styles. Availability is inconsistent, and their selection is narrower than dedicated mattress retailers.
What size is a king box spring?
A standard king box spring measures 193 x 203 cm (76 x 80 inches). Because of its large size, king box springs are often sold as a split king (two twin XL box springs side by side), which makes them easier to move up stairs and through doorways.
Do I need a split king box spring?
A split king box spring (two twin XL pieces) is necessary if you need to navigate the box spring around tight corners, up staircases, or through narrow doorways. A one-piece king box spring is only practical in ground-floor bedrooms or spaces with wide stairways and halls.
What is the alternative to a king box spring?
A low-profile box spring (14 cm / 5.5 inches tall) or a king platform bed with slatted support is an alternative. Platform beds eliminate the box spring entirely and work with most foam and hybrid mattresses. Adjustable bases are another option that replaces both box spring and standard frame.
Sources
- Sleep Foundation, "King vs. California King: Size Comparison," 2025
- Better Sleep Council Canada, "Foundation Requirements for King Mattresses," 2024
- Canadian Standards Association, "Residential Stair Dimensions," 2023
Visit Our Brantford Showroom
Mattress Miracle carries king box springs, low-profile foundations, and platform bases for king mattresses. Come in and we will help you find the right foundation for your mattress type and bedroom layout.
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.
Serving Brantford, Hamilton, Cambridge, and all of South Western Ontario.
Shop This Topic at Mattress Miracle
Bed frames at Mattress Miracle:
- Almonte Canadian Bed Frame
- Canadian Made Platform Bed
- Bridgewater Storage Bed Frame
- Hickory Ridge Platform Bed
Or bed frames in our Brantford showroom.