Firmness is the thing people most often get wrong with a new mattress, mostly because the labels aren't standard. One maker's medium firm is another's firm. The scale is still useful once you know what it's describing and how your weight and sleeping position shift it.
What the labels mean
Most listings use a scale something like this:
- Soft or plush: you sink in noticeably. Mostly suits lighter people and side sleepers.
- Medium: some give at the shoulders and hips, but you're still on top of the mattress.
- Medium firm: the most common rating, and where most people end up. Enough give to be comfortable, firm enough that your hips don't sink.
- Firm: very little give. Often suits heavier people and front sleepers.
Some makers use a 1 to 10 scale instead, with 10 the firmest. Medium firm sits around 6 or 7 on that scale.
Start with your sleeping position
How you lie matters more than anything else. The aim is to keep your spine in roughly the same line as when you're standing up straight.
Side sleepers put their weight on a shoulder and a hip, the widest parts of the body. They need a surface that lets those sink in a little, so medium or medium firm with a memory foam top usually works. Go too firm and you may wake up with a dead arm.
Back sleepers do well on medium firm. The mattress should fill the small of your back without letting your bottom sink.
Front sleepers need firmer support, because a soft mattress lets the hips drop and arches the lower back. Firm, or the firmer end of medium firm, is usually better.
If you move around a lot through the night, medium firm is the safe middle ground.
Then think about your weight
Firmness ratings assume an average adult. If you're lighter, a mattress will feel firmer to you than its label says. If you're heavier, it'll feel softer, because you sink further into the comfort layers. As a rough guide, people under about 60kg often prefer a step softer than their position suggests, and people over about 100kg a step firmer.
Couples of very different weights usually settle on medium firm. A pocket sprung or hybrid mattress helps here too, because each side responds to the person lying on it.
What orthopaedic means on a listing
You'll see the word orthopaedic on a lot of mattresses. It isn't a regulated term and it doesn't mean the mattress is a medical product. In practice it usually means a firmer, more supportive build, often with zoned springs or foam. If you have a back condition, your GP or physio is the right person to ask about firmness.
If you can't decide
A dual-sided mattress takes some of the risk out of it. Our cooling gel memory foam mattress has a medium firm gel foam side and a firm side. You unzip the cover and turn the core over if the first side isn't right for you.
A topper is the other safety net. It's easier to soften a firm mattress with a topper than to firm up a soft one, so if you're torn between two ratings, the firmer one is usually the safer pick.
Examples from our range
- Medium soft: the 20cm pocket sprung mattress, listed as suiting sleepers under 70kg.
- Medium firm foam: the 20cm memory foam mattress with a 4cm memory foam top over 16cm of support foam.
- Medium firm hybrid: the 30cm memory foam hybrid with 7 zones of pocket springs.
- Firm: the 3-zone pocket sprung mattress, 25cm deep, in single, small double and king.
You'll find the firmness in the specifications on most product pages. Browse the full memory foam and pocket sprung and hybrid ranges. Delivery is free to the Republic of Ireland and Northern Ireland, and most orders arrive in 3 to 7 days.