How thick should a mattress be?
Hi, we’re John and Mimi. After “which size?”, the next question we hear is “How thick should my mattress be: 8, 10, 12 or 14 inches?” Thicker isn’t automatically better. The right thickness depends on your weight, how you sleep, and what the mattress sits on. Here is a plain-English guide, plus our mattresses in every thickness at today’s prices: same factory models, lower price than other online retailers.
The short answer
- 10" to 12" fits most adults. It’s the sweet spot for comfort, support and price, and it bends well on an adjustable base.
- 12" to 14" if you’re a heavier sleeper, a side sleeper who wants more cushion, or you just like a plush, hotel-style bed.
- 6" to 8" for kids, bunk beds, daybeds, trundles and guest rooms, or anyone who wants a firm, simple bed for less.
Mattress thickness chart
| Thickness | Best for | Keep in mind |
|---|---|---|
| 6" | Bunk beds, trundles, daybeds, kids, occasional guests | Firm and low; adults may feel it’s thin for every night |
| 8" | Kids and teens, guest rooms, stomach sleepers who like firm | A good budget everyday bed for lighter adults |
| 10" | Most adults, back sleepers, adjustable bases, dorms | The best value for everyday sleep |
| 12" | Side sleepers, couples, anyone who wants a thicker comfort layer | Our most popular thickness |
| 14" | Heavier sleepers, plush lovers, tall bed frames | Needs deep-pocket sheets and raises the bed height |
What the thickness actually changes
Every mattress has two parts: a support core at the bottom (dense foam or pocket coils) that keeps your spine straight, and comfort layers on top (memory foam, gel foam) that cushion your shoulders and hips. A thicker mattress usually means more comfort layers, a deeper core, or both. That can feel plusher and support heavier bodies better, but the feel (firm, medium, plush) comes from the materials, not the inches. A 12" firm mattress is still firm.
Pick by body weight
This is a rule of thumb, not a hard rule:
- Under about 130 lbs: 8" to 10" is usually plenty. Lighter sleepers don’t sink far enough to use a very thick comfort layer.
- About 130 to 230 lbs: 10" to 12" works for most people.
- Over about 230 lbs, or two adults sharing: 12" to 14", so you sink in without bottoming out. A hybrid with pocket coils adds extra push-back and edge support.
Pick by sleeping position
- Side sleepers need room for the shoulder and hip to sink in, so 12" or more with a softer top is the usual pick. See our best mattress for side sleepers guide.
- Back sleepers do well on 10" to 12", medium to medium firm.
- Stomach sleepers want the hips to stay level, so a firmer 8" to 12" often beats a thick plush bed. See our firm mattress guide.
Pick by what the mattress sits on
- Adjustable base: 10" to 14" memory foam or hybrid bends best. Very thin mattresses can feel the base underneath; very thick ones bend a little stiffer at the fold. More in our best mattress for an adjustable base guide.
- Bunk bed or loft bed: check the label on the bunk for its maximum mattress thickness and stay at or under it, so the guard rail still sits well above the mattress. That usually means a 6" or 8" mattress.
- Trundle or daybed: 6" to 8", so the trundle still slides under.
- Platform bed or tall frame: any thickness works; just add up frame height plus mattress so the bed isn’t too high to sit on comfortably. Most people like the top of the mattress about knee height.
Don’t forget the sheets
Standard fitted sheets usually fit mattresses up to about 12". For a 14" mattress, or a 12" mattress with a mattress protector, look for deep-pocket sheets. Our bedding is cut for mattress-and-adjustable-base sets.
Our mattresses in every thickness at today’s prices
| Pick | Best for | Model code | Full | Queen | King |
|---|---|---|---|---|---|
| 6" Essentials Firm | Bunk beds, trundles, daybeds and guest rooms | 6ESS-F |
$289 | $299 | — |
| 8" Daisy Firm | Kids, teens and stomach sleepers who like firm | 8BNV-F |
$359 | $389 | $429 |
| 10" Rose Medium | Best value everyday bed for most adults | 10BNV-F |
$399 | $429 | $479 |
| 10" EcoCore Hybrid Premium | Pocket-coil bounce in a 10" profile | 10HSOY-F |
$509 | $549 | $639 |
| 12" Copper Gel | Our most popular thickness and feel | 12BNCOPPER-F |
$499 | $529 | $609 |
| 12" iSwitch Flippable | Two feels in one: flip for medium soft or medium firm | 12ISWITCH-F |
$559 | $569 | $689 |
| 14" ActiveAlign Zoned Hybrid | Plush and supportive for heavier sleepers | 14REACTIVE-F |
$669 | $689 | $839 |
Prices are today’s prices, read live from our catalog, with free FedEx shipping included.
10" Rose - Medium Firmness - 10BNV
If you’re not sure, start here. A 10" medium-firm mattress suits most adults, works on any frame or adjustable base, and keeps the price low.
- 2" gel air memory foam over support foam, medium firm
- Bends well on an adjustable base
- 10-year limited warranty, ships compressed in a box, free FedEx shipping
From $329 (Twin) · Queen $429 · See sizes & details
12" Copper Gel Infused Cooling Memory Foam Mattress - Medium Firm, Back & Side Sleepers
The thickness most of our customers pick: a deeper copper-gel comfort layer for side and back sleepers, without the extra height of a 14".
- 12" copper-gel infused memory foam
- Medium firm, for back and side sleepers
- Every size, including split king
From $409 (Twin XL) · Queen $529 · See sizes & details
Questions we hear a lot
How thick should a mattress be for an adult?
For most adults, 10 to 12 inches is the sweet spot for comfort, support and price. Heavier sleepers, side sleepers and people who like a plush bed often prefer 12 to 14 inches.
Is a thicker mattress better?
Not automatically. Thickness adds room for comfort layers and support, but the feel comes from the materials. A 12 inch firm mattress is still firm, and lighter sleepers often don’t need more than 8 to 10 inches.
What thickness mattress is best for an adjustable base?
Memory foam or hybrid mattresses from 10 to 14 inches bend best on an adjustable base. Very thin mattresses can let you feel the base, and very thick ones bend a little stiffer at the fold.
What thickness mattress do I need for a bunk bed?
Check the bunk bed’s label for its maximum mattress thickness and stay at or under it so the guard rail sits well above the mattress. That usually means a 6 or 8 inch mattress.
Do I need deep-pocket sheets for a 14 inch mattress?
Usually yes. Standard fitted sheets fit up to about 12 inches, so a 14 inch mattress, or a 12 inch one with a mattress protector, needs deep-pocket sheets. Questions? Text John at 805-617-6878.
Still deciding? Just ask us
Tell John your weight range, how you sleep and what the mattress will sit on, and he will tell you honestly which thickness fits. Text or call 805-617-6878, 6 AM to 9 PM Pacific, take the 60-second mattress quiz, or check the mattress size chart. See our Purchase Policy & Warranty for the details.
Written by John & Mimi, MimiJohn. Prices update automatically.