The short answer: On the common 10-point scale, 1–3 is soft, 4–5 medium-soft, 5–6 medium, 6–7 medium-firm, 7–8 firm and 8–10 extra firm. Most people with back pain start at 6–7. Makers' labels are not standardized: when a maker prints a number, we show it; when it only prints a word, we translate it using the table below.
The scale
| Scale | Common label | Who it usually suits |
|---|---|---|
| 1–3 | Soft, plush | Very light side sleepers; rarely right for back pain |
| 4–5 | Medium-soft, medium plush | Light side sleepers with shoulder pain |
| 5–6 | Medium | Side and combination sleepers of average weight |
| 6–7 | Medium-firm | Most people with back pain; back sleepers |
| 7–8 | Firm | Stomach sleepers; heavier back sleepers |
| 8–10 | Extra firm, ultra firm | Stomach sleepers who sink on everything; some heavier sleepers |
How we translate makers' labels
Where a maker prints a number (Leesa 5–7 and 6–8, Zinus 7–8, BedStory 7, Purple 4 of 5, the Plank's "ten"), we show it and mark it as the maker's. Where a maker only prints a word, we map it: Plush and Soft to 3–4, Medium Plush to 4–5, Medium to 5–6, Medium Firm to 6–7, Firm to 7–8, Extra and Ultra Firm to 8–9. Every product card says which kind of number you are looking at.
Why labels disagree
There is no industry standard. One maker's "firm" can be another's "medium-firm". Body weight changes how a bed feels: a 120-lb sleeper and a 250-lb sleeper describe the same mattress differently. And comfort layers matter: a pillow top over a firm core feels soft at first and firm underneath.
Where the trials point
The best-known trial on firmness and back pain compared firm and medium-firm beds and found medium-firm better for chronic low back pain. That is why we start most readers at 6–7. See firm vs medium-firm and what the research says.
Reader questions, answered
What is a medium-firm mattress on a 1–10 scale?
Roughly 6–7.
Is 7 out of 10 firm?
It is the firm end of medium-firm, and many makers would call it firm.
We write about mattresses, not diagnoses. Numbness, leg weakness, bladder or bowel changes, or pain after a fall are reasons to see a doctor, not reasons to shop. Full disclaimer.