A box spring is a mattress support system featuring a sturdy, slatted frame and shock-absorbing steel coils. Although they are not required, box springs provide strong reinforcement for your mattress, which helps to prevent sagging and other wear and tear. Consistent support night after night can also improve your overall sleep quality.
Keep reading to learn about how box springs are constructed, which types of mattresses they're best suited for, and some pros and cons of using them.
What Is a Box Spring?
A box spring is constructed from a wooden or metal frame encased in fabric or cloth. The frame contains steel coils arranged in a grid pattern. These coils act as shock absorbers that allow the box spring to support a mattress and its sleepers. The top of the frame is slatted. The slats are evenly spaced to ensure even support across the surface.
You can set a box spring directly on the floor, but many prefer to place their box spring inside a bed frame with with mattress resting on top. This elevates the bed's overall height, making it easier to get on and off the mattress, and the area beneath the frame can serve as bonus storage space.
Although dimensions vary by model, box springs fall into the following two size categories:
- Standard or high-profile: 9 inches (22.9 centimeters)
- Low-profile: 5 to 6 inches (12.7 to 15.2 centimeters)
Box springs also vary in terms of pricing. The cost of a box spring depends on its size, materials, and manufacturer. The average model costs about $100 to $300 in a queen size, but luxury box springs can cost $500 or more.
To ensure a box spring remains supportive over the years, you'll want to regularly rotate it head-to-foot every three to six months. Rotating your mattress in this manner can also prevent wear and tear, so we recommend rotating both the bed and box spring at the same time.
When Do You Need a Box Spring?
Most box springs are compatible with different mattress types. However, the shock absorption from the coils makes them particularly well suited for innersprings and hybrids. These beds tend to be heavier and bouncier. A strong box spring will adequately support the innerspring or hybrid and prevent wear and tear over time.
Regardless of your mattress type, you'll need a box spring if you use a wooden or metal bed frame. Without the box spring, most frames are not strong enough to support the mattress and distribute its weight. For platform beds or adjustable beds, you won't need a box spring. These support systems are designed to support you and the mattress without the box spring component.
Choosing a Box Spring
Before selecting a box spring, double-check the size of your mattress. Using an incorrectly sized box spring can cause significant sagging and wear and tear. Most mattresses sold today come in six standard sizes:
- Twin: 39 inches wide x 75 inches long
- Twin XL: 39 inches wide x 80 inches long
- Full/double: 54 inches wide x 75 inches long
- Queen: 60 inches wide x 80 inches long
- King: 76 inches wide x 80 inches long
- California King: 72 inches wide x 84 inches long
Box springs are designed to match these dimensions, but some models are not available in certain sizes. Take time to measure the dimensions of your bed frame, as well as your bedroom or wherever you plan to use the box spring.
Also, be sure to read the fine print of your mattress warranty. A warranty will usually list specific criteria for your bed's support system, including the maximum distance between the slats. Most warranties do not permit slats to be more than two to three inches apart. The warranty may also require frames with five to six legs and center support beams for larger mattress sizes.
If you don't use an acceptable support system and mattress damage occurs, the manufacturer may void the warranty.
Box Spring Pros and Cons
Box Spring Alternatives
Instead of a box spring, you may choose to use one of these other support systems with your mattress:
- Foundation: Foundations feature a wooden or metal frame encased in fabric, but they do not include the coils found in box springs. The top surface is flush, not slatted. This makes foundations more supportive for mattresses that tend to sag through slats, such as all-foam beds. Like box springs, a foundation can also be used in tandem with a bed frame to support the mattress, or rest freely on the floor.
- Platform bed: A platform bed consists of a slatted metal or wooden frame, along with legs and a center support bar to elevate the mattress. Platforms may also include headboards, posts, and other features that add to your bedroom decor. You don't need a box spring or foundation when you use a platform bed, but check the slat dimensions to make sure it meets your mattress warranty requirements.
- Adjustable bed: Adjustable beds can be lowered and elevated at the head and foot. This allows owners to customize the angle of their sleep positions. Most of these beds allow for each side to be adjusted independently for couples with differing angle preferences. Adjustable beds, like platform beds, can support a mattress without a box spring or a foundation.