Short answer: firmness is rated 1 to 10, and the right number depends on how you sleep and what you weigh, not on what feels nice for thirty seconds in a store. Side sleepers want 4–6. Back sleepers want 6–7. Stomach sleepers want 7–9. Heavier bodies should move up about a point; lighter bodies down about a point.
The 1 to 10 scale, in plain terms
- 1–2, extra soft: you sink in. Almost nobody should buy this.
- 3–4, soft: deep cushioning at the shoulder and hip.
- 5–6, medium: some sink, some push back.
- 6.5–7, medium-firm: where most mattresses sold in America land, and the safest guess if you truly do not know.
- 7.5–10, firm: you sleep on top of it rather than in it.
Start with how you sleep
Lie the way you actually fall asleep, not the way you think you sleep. Your spine should stay in roughly the same straight line it holds when you are standing up.
| Position | Firmness | Why |
|---|---|---|
| Side | 4–6 | The shoulder and hip need somewhere to go, or they take all the pressure |
| Back | 6–7 | Enough give for the lower back, enough support that the hips do not drop |
| Stomach | 7–9 | Anything softer lets the hips sink and arches the lower back all night |
| Changes all night | 5–7 | Medium-firm is the compromise that does not fight any position |
Then adjust for body weight
The same mattress feels different under different bodies, because firmness is really about how far you push into it. A 6 under a 120-pound person feels like a 7; under a 250-pound person it feels like a 5.
| Weight | Side | Back | Stomach |
|---|---|---|---|
| Under 130 lbs | 4–6 | 5.5–6.5 | 6.5–7.5 |
| 130–230 lbs | 5–6 | 6–7.5 | 7–8 |
| Over 230 lbs | 5–7 | 6.5–8 | 8–10 |
When two people disagree
This is the most common problem we hear at the counter. Three ways out, in order of how well they work:
- Split the difference and go medium-firm. Works more often than people expect, because most disagreements are one or two points apart, not five.
- Buy for the heavier partner and add a topper on the lighter partner side. A topper can soften a mattress; nothing can firm up one that is too soft.
- If one of you is a side sleeper and the other sleeps on their stomach, that gap is real. Look at a split king, or accept that one of you is compromising.
Signs you bought the wrong firmness
- Lower back sore in the morning: usually too soft — your hips are sinking.
- Shoulder or hip aching, numb arm: usually too firm for a side sleeper.
- You wake up and roll around all night: your body is hunting for a position the mattress does not support.
- Fine for the first month, sore after six: that is the comfort layer breaking down, not the firmness.
How to test one in a store in five minutes
Lie down in your sleeping position for at least five full minutes — not ten seconds sitting on the edge. Slide a hand into the gap at your lower back: if it slips in easily, the mattress is too firm for you; if you cannot get it in at all, too soft. Then get up. If standing up takes effort, that mattress is softer than you want.
What we have right now
We carry liquidation mattresses in every size, memory foam and hybrid, and we will tell you straight which one suits how you sleep.
Common questions
Is a firmer mattress better for your back?
Not automatically. That is an old rule of thumb. What helps a back is keeping the spine level, which for most people is medium-firm, around 6 to 7 — not the firmest thing in the store.
Can a mattress be broken in?
Somewhat. Most soften slightly over the first thirty nights. But a mattress that is two points too firm will not become the right one.
Does a topper fix the wrong firmness?
It can soften a mattress that is too firm. It cannot make a too-soft mattress support you, because the sinking is happening underneath the topper.
What firmness should I buy for a guest room?
Medium-firm, 6 to 7. You do not know how your guests sleep, and that is the range that suits the most people.
Sources: Mattress Clarity firmness guide. Comfort is personal — this is general information, not medical advice.
Come see it in person
Everything on our floor comes from overstock and store liquidations, so the selection changes weekly and most pieces are one of one. If you tell us what you are trying to solve, we will point you at what actually fits.
Financing through Snap Finance, Koalafi, Acima and Kafene, with no perfect credit needed. How the financing works. Same-day delivery on all items, priced by distance, up to 150 miles. Delivery zones and prices.
Tony Discount Furniture and Mattresses
6650 E WT Harris Blvd, Unit C, Charlotte, NC 28215
(704) 390-1713 · Monday to Saturday 11am–7pm, Sunday 2pm–6pm
Se habla espanol.