Best mattress for bunk beds, trundles and daybeds
Hi, we’re John and Mimi. Bunk beds, loft beds, trundles and daybeds all have one thing in common: the frame decides the mattress, not the other way around. Get the size and thickness right and the bed is safe, the trundle slides away and the sheets stay put. Here’s what to check before you buy, which of our thinner mattresses we’d pick for each spot, and today’s prices: same factory models, lower price than other online retailers.
The short answer
- Follow the bed’s own label. Bunk beds sold in the US have to be labeled with the right mattress size and the maximum mattress thickness. Stay at or under it. On many top bunks that means a 6" to 8" mattress.
- Keep the guardrail well above the mattress. US bunk bed rules require the top of the guardrails to be at least 5 inches above the top of the mattress when the thickest mattress the maker allows is on the bed. A thicker mattress than the label allows takes that margin away.
- Trundles: measure the space between the trundle platform and the bed above. A 6" mattress fits most; some trundles have room for 8".
- Daybeds: usually a twin, 8" to 10", with a firmer feel so it holds up as a sofa too.
- Size: most bunks, trundles and daybeds take a regular twin (38" × 75"), not a Twin XL. See our twin vs Twin XL guide if you’re not sure.
Before you buy: measure and read the label
- Find the bed’s label or instructions. They list the mattress size (twin, Twin XL or full) and the maximum thickness. If the label is gone, look up the bed’s model online or ask the maker before you go thicker.
- Count anything under the mattress, too. The maximum usually covers the mattress plus any foundation or bunkie board, so a 1" board under an 8" mattress counts as 9".
- Match the size exactly. The mattress should fill the frame without big gaps at the sides or ends, where a child’s arm or leg could slip through. Measure inside the frame if you’re unsure.
- Check the support. The setup instructions for these mattresses call for a solid surface, an adjustable base, or slats no more than 2" apart. Many bunk and trundle frames have wider slats, so a thin bunkie board or plywood panel helps (and counts toward the maximum thickness).
Bunk bed and loft bed safety basics
A few rules every bunk bed maker has to print in the instructions under US safety rules, and they’re worth repeating to the kids:
- Don’t let children under 6 use the upper bunk.
- Use guardrails on both sides of the upper bunk, and put the full-length guardrail against the wall if the bed has only one.
- Only one person on the upper bunk, use the ladder to get in and out, and no horseplay on or under the beds.
Loft beds count too: under the US rules, any bed whose mattress foundation sits more than 30 inches off the floor is treated as a bunk bed. Follow the label for mattress thickness and keep the rail well above the mattress top. The bed frame’s own instructions always come first.
Pick by bed type
| Bed | What to look for | Our picks |
|---|---|---|
| Top bunk or loft bed | The label’s maximum thickness (often 6" to 8"), firm, stays put | 8" Daisy Firm, 8" Gel Comfort Reactive |
| Bottom bunk | Check the label and keep headroom for sitting up | 8" Daisy Firm, 10" Rose Medium if it fits |
| Pull-out trundle | Thin enough to slide under, usually 6" | 6" Essentials Firm, 8" Daisy Firm if there’s room |
| Daybed | Twin, 8" to 10", firmer so it works as a sofa | 8" Daisy Firm, 10" Gel Comfort Reactive, 10" Rose Medium |
| Twin-over-full bunk | A full on the bottom; check both labels | 6" Essentials Firm, 8" Daisy Firm (both come in full) |
| Teen or adult on a bunk | The thickest the label allows; Twin XL only if the frame is Twin XL | 8" Daisy Firm (twin or Twin XL), 8" Gel Comfort Reactive |
Trundle beds: getting the fit right
- Roll-out trundles slide under the main bed. Measure from the trundle’s platform up to the bottom of the bed rail or slats above it, and leave a little room so it rolls in easily. That gap is your maximum thickness.
- Pop-up trundles rise to sit next to the main bed. They still have to roll under it first, so the same measurement applies.
- Our 6" Essentials Firm is made for spots like this: its description lists trundle beds, sofa-bed furniture and any space that needs a shorter profile. Check the table below for the sizes in stock today.
Daybeds: a bed and a sofa
A daybed is a twin mattress that spends its days as seating, so it gets sat on along the front edge far more than a normal bed. A firmer mattress holds that edge better. A thicker mattress raises the seat and hides more of the back and side rails, so check how much rail you want showing. Many daybeds look best with an 8" to 10" mattress, but if yours has a trundle underneath, measure that space separately. A washable cover is a plus for a bed that guests and kids sit on all day.
Is a thin mattress comfortable enough?
For kids, usually yes. Lighter bodies don’t sink in as far, so a 6" or 8" mattress feels plenty supportive to most children. Teens and adults who sleep on a bunk or daybed every night may find a thin mattress firm, so pick the thickest one the label allows. For a main bed, our mattress thickness guide covers the full 6" to 14" range.
Bunk, trundle and daybed mattress prices today
Our lower-profile mattresses in twin, full and Twin XL, at today’s prices. A dash means that size isn’t available right now.
| Pick | Best for | Model code | Twin | Full | Twin XL |
|---|---|---|---|---|---|
| 6" Essentials Firm | Trundles, sofa beds and low-profile spaces | 6ESS-T |
— | $289 | — |
| 8" Daisy Firm | Top bunks and daybeds: firm, non-skid bottom | 8BNV-T |
$309 | $359 | $309 |
| 8" Gel Comfort Reactive | Budget pick for bunks and guest beds | 8ESSCA-T |
$292 | $329 | $298 |
| 10" Gel Comfort Reactive | Daybeds and bottom bunks with room to spare | 10ESSCA-T |
$329 | $379 | $329 |
| 10" Rose Medium | Daybeds and bottom bunks for older kids and teens | 10BNV-T |
$329 | $399 | $339 |
Prices are today’s prices, read live from our catalog, with free FedEx shipping included.
Need the exact inches for every size? See the mattress size chart, or compare every model in the mattress comparison chart.
8" Daisy - Firm Mattress - 8BNV
Our pick for most top bunks and daybeds. At 8" it suits bunks and daybeds whose label allows 8", and the firm feel and non-skid bottom help it sit flat and stay put.
- 2" gel air memory foam over a 6" Air Grid base
- Non-skid bottom fabric
- Zip-off, machine-washable cover
- CertiPUR-US certified foam
From $309 (Twin) · Queen $389 · See sizes & details
8" Gel Infused Comfort Reactive Memory Foam Mattress - Firm, Back & Stomach Sleepers
Our budget pick for kids’ bunks, guest daybeds and the second bed in a shared room, made in twin, Twin XL and full.
- 8" all foam with a firm feel
- Gel-infused air memory foam and Air Channel base foam
- Quilted cover
- CertiPUR-US certified foam
From $292 (Twin) · Queen $349 · See sizes & details
Tips for setting up a bunk, trundle or daybed mattress
- Put it in place before you open it. Our mattresses arrive rolled in a box. Lift the rolled mattress onto the top bunk or into the trundle first, then cut the plastic with scissors (not a blade). It’s much easier than wrestling an expanded mattress up a ladder.
- Give it time to expand. You can sleep on it the first night, and it can take up to 72 hours to fully recover its shape. More in our mattress-in-a-box guide.
- Use a mattress protector. Liquid spills aren’t covered by the warranty, so a waterproof protector is worth it on kids’ beds.
- Rotate it head to foot every few months so one spot doesn’t wear faster. Don’t let kids jump or stand on it.
- Buy fitted sheets for the exact size. Thin mattresses don’t need deep-pocket sheets, and snug sheets are easier to change on a top bunk.
Shop this guide
Start with the 8" Daisy for most bunks and daybeds, the 6" Essentials for trundles, or the 8" Gel Comfort Reactive to save a little.
- 8" Daisy - Firm Mattress - 8BNV, from $309. Firm 8" mattress with a non-skid bottom for bunks and daybeds.
- 6” Essentials Firm Memory Foam Mattress - 6ESS, from $289. Low-profile 6" mattress made for trundles and sofa beds.
- 8" Gel Infused Comfort Reactive Memory Foam Mattress - Firm, Back & Stomach Sleepers, from $292. Budget-friendly 8" pick for kids’ rooms and guest beds.
Questions we hear a lot
How thick should a bunk bed mattress be?
No thicker than the maximum on the bunk bed’s label or instructions, counting any bunkie board underneath. On many top bunks that means 6 to 8 inches. US bunk bed rules require the top of the guardrails to be at least 5 inches above the mattress when the thickest allowed mattress is used.
What size mattress fits a trundle bed?
Most trundles take a regular twin (38 by 75 inches). For thickness, measure from the trundle platform to the bottom of the bed above it and leave a little room so it rolls in easily. A 6 inch mattress fits most trundles; some have room for 8 inches.
Can I use a regular mattress on a bunk bed?
Only if it is the size the bunk calls for and no thicker than its label allows. A typical 10 to 12 inch mattress is often too thick for a top bunk because it brings the sleeper too close to the top of the guardrail.
What is the best mattress for a daybed?
Most daybeds take a twin. An 8 to 10 inch mattress with a firmer feel works well because a daybed is sat on like a sofa during the day. If the daybed has a trundle, measure that space separately.
Can a mattress in a box go on a top bunk?
Yes. Lift the rolled mattress onto the bunk before you open it, then cut the plastic with scissors. Our setup instructions call for a solid surface or slats no more than 2 inches apart, and it can take up to 72 hours to fully expand. Questions? Text John at 805-617-6878.
Still deciding? Just ask us
Send John the bed’s maximum mattress thickness from the label (or a photo of it), the size, and who’s sleeping there, and he’ll tell you honestly which mattress fits. Text or call 805-617-6878, 6 AM to 9 PM Pacific, take the 60-second mattress quiz, or use Help me choose. See our Purchase Policy & Warranty for the details.
Written by John & Mimi Venti, MimiJohn. Specs from the manufacturer; prices update automatically. Bunk bed safety points summarize the US Consumer Product Safety Commission’s bunk bed requirements; always follow your bed frame’s own label and instructions.