When buying a king size mattress, one of the most common questions people ask is: Do you need a box spring with a king size mattress? Box springs used to be traditionally viewed as the necessary tools to support mattresses, to add height, and enhance airflow. But, the necessity of box springs is not so intuitive with the introduction of modern bed frames, slatted bases, and platform beds. In this guide, we will examine the strengths and weaknesses of investing in a box spring, compare and contrast alternatives, and tell you whether you should invest in a box spring or not- or you can save some money by doing something else.
What Is a Box Spring and Why Was It Popular?
A box spring is a wooden or metal frame filled with springs or coils, designed to provide support and shock absorption under a mattress.
- Traditional role: Elevates the mattress, reduces wear and tear, and improves ventilation.
- Then vs. Now: Modern mattresses like memory foam, latex, and hybrids are designed to work best with solid or slatted foundations, making box springs less essential today.
Do You Need a Box Spring with a King Size Mattress?
The short answer: Not always. It depends on your bed frame, mattress type, and sleeping preferences.
Situations Where a Box Spring Helps
- You have a traditional innerspring mattress.
- Your bed frame requires a box spring for proper support.
- You prefer added height for getting in and out of bed.
Situations Where You Don’t Need One
- You use a platform bed or slatted frame.
- Your mattress is memory foam, latex, or hybrid.
- You want to save money and reduce bulk in your bedroom.
Box Spring vs. Modern Bed Frames (Comparison Table)
| Feature | Box Spring | Platform/Slatted Bed Frame |
|---|---|---|
| Support | Best for innerspring | Works for all mattress types |
| Height | Adds 8–12 inches | Lower profile, sleeker look |
| Durability | Can wear out over time | Typically longer-lasting |
| Cost | $100–$300 | $150–$500+ (depending on style) |
| Airflow | Good | Excellent |
Pros and Cons of Using a Box Spring
Pros
- Elevates your mattress for easier access
- Provides support for older innerspring mattresses
- Improves airflow and breathability
Cons
- Unnecessary for many modern mattresses
- Adds extra cost ($100–$300)
- Can sag or lose support over time
Cost Savings: Box Spring or No Box Spring?
Skipping the box spring can save you $100–$300 upfront. Instead, you can invest in:
- A platform bed frame ($150–$400)
- A slatted frame for airflow and support
- A bunkie board (thin foundation) for extra reinforcement
👉 Check out our guide: Ultimate King Size Mattress Buying Guide 2025
FAQs About Box Springs and King Size Mattresses
Q1: Can I use a king size mattress without a box spring?
Yes. Most modern mattresses work perfectly on platform beds, slatted frames, or adjustable bases.
Q2: Does a box spring make a mattress last longer?
Only for older innerspring mattresses. For memory foam or hybrid mattresses, a solid foundation is better.
Q3: What happens if I don’t use a box spring?
Nothing—if your mattress is on a proper frame. But without support, it may sag or void the warranty.
Q4: Do adjustable bed frames replace box springs?
Yes. Adjustable bases are designed for direct mattress placement, eliminating the need for box springs.
Conclusion
So, do you need a box spring with a king size mattress? This will depend on how you have set it up. A box spring can still help you provided that you have a conventional inner spring mattress or have an old bed frame. However, when you have a modern memory foams/hybrid/latex mattress, a platform/slatted frame will save you the money and provide better support.
Your turn: Do you have a box spring under your king size mattress or did you omit it? Write about your experience in the comments section!