Day Bed, Trundle & Shorty Mattress Sizes: UK Mattress Size Guide
Day beds, trundle beds and shorty beds often need a mattress that isn't a standard size — and getting it wrong means a trundle that won't slide shut, a day bed that looks like a bed rather than a sofa, or a mattress that hangs over the frame. This guide explains which mattress each type of bed takes, the sizes and depths to look for, and which of our mattresses fit.
The golden rule: always check the mattress size and maximum depth stated on your bed's product page before ordering. Every bed we sell lists exactly what it needs.
Quick size guide
| Bed type | Typical mattress size | Depth |
| Trundle / pull-out guest bed | 90 x 190cm | Slimline, around 10cm |
| Day bed (sofa-style) | 90 x 190cm or 90 x 200cm | Slimline 10cm, or a standard single up to the bed's maximum |
| Shorty / junior bed | 70 x 160cm | 12–14cm |
| Grow / extending bed | 90 x 140cm, extending to 90 x 190cm | 12cm |
| UK single | 90 x 190cm | 14–15cm |
| Continental (European) single | 90 x 200cm | 14–15cm |
| Small double | 120 x 190cm or 120 x 200cm | 15cm |
| Double | 140 x 190cm or 140 x 200cm | 15cm |
Trundle mattresses
A trundle is a second bed that slides out from under the main bed, so its mattress has to be slim enough to roll back underneath. A standard 14–15cm single mattress is usually too deep — it will stop the trundle closing.
Most trundle beds take a 90 x 190cm mattress around 10cm deep. Our Sleeptight Trundle Mattress 90 x 190cm (Purple Label) — £109 — is made for exactly this: 10cm deep, medium-firm, UK-made with a washable cover.
It's the trundle option for beds including the Heritage Bunk Bed with Optional Trundle, the Heritage 3 Trio Sleeper and the Heritage Day Bed. Browse all trundle mattresses or beds with trundle & sleepover beds.
Trundle mattress tips
- Check the trundle's maximum mattress depth on the product page — it's often lower than for the main bed.
- A trundle mattress is designed for sleepovers and regular guest use. For a child sleeping on it every night, a full-depth mattress on a main bed is more comfortable.
- Rolled mattresses need around 24 hours to expand fully once unpacked.
Day bed mattresses
A day bed is a single bed with a back and sides, designed to look and work like a sofa during the day. Which mattress it takes depends on the design:
- Standard day beds take a normal single mattress — for example, the Parisot Sleep Day Bed (£399) and the Kids Avenue Haven Storage Day Bed (£329) both take a 90 x 200cm continental single.
- Pull-out guest day beds use slimline mattresses so the guest bed fits underneath. The Kids Avenue Heritage Day Bed (£349) takes one 90 x 190 x 10cm trundle mattress for everyday use, or two side by side when it opens out into a super king size guest bed.
If you'd like a day bed to feel more like a sofa, a slimmer mattress keeps the seat lower and firmer. Our Sleeptight Daybed Mattress 90 x 190cm (Light Blue Label) — £119 — is 10cm deep with a low, sofa-like profile.
See all daybed mattresses, our day beds, or our Day Beds Buying Guide.
Shorty mattresses (70 x 160cm)
Shorty or junior beds are shorter and narrower than a standard single, designed for young children moving out of a cot or toddler bed. They take a 70 x 160cm mattress — a standard single will not fit.
- Sleeptight Shorty Junior Mattress 70 x 160cm (Dark Green Label) — £179, 12cm deep, medium-firm, UK-made
It suits our Junior Shorty Beds and Hoppekids shorty beds. A shorty bunk takes two. Browse junior & shorty mattresses, or read The Benefits of a Shorty Bed.
Grow bed mattresses (90 x 140cm to 90 x 190cm)
Extending "grow with me" beds start short for a toddler and lengthen to a full single. Our Sleeptight Grow Bed Mattress (White Label) — £229 — is 90 x 140cm and 12cm deep; add the second piece to extend it to 90 x 190cm when the bed is lengthened. Check your extending bed's mattress sizes on its product page before ordering.
Single mattresses: 90 x 190cm vs 90 x 200cm
This is the most common mix-up. A UK single is 90 x 190cm; a continental (European) single is 90 x 200cm. Many of the European-made beds we sell — including several from Parisot and Thuka — take the longer 200cm size. A 190cm mattress in a 200cm frame leaves a gap; a 200cm mattress won't fit a 190cm frame.
We stock both sizes in a choice of comfort types, all 14–15cm deep:
- Foam: Sleeptight Junior 90 x 190cm (Blue Label) or 90 x 200cm (Green Label) — £179
- Pocket sprung: Sleeptight Pocket 90 x 190cm (Yellow Label) or 90 x 200cm (Red Label) — £259
- Memory foam: Sleeptight Memory 90 x 190cm (Black Label) or 90 x 200cm (Grey Label) — £319
- Traditional (not rolled), 90 x 200cm: Kids Avenue Superior Sprung — £179, or Kids Avenue Pocket Sprung — £259
Browse single bed mattresses and bunk bed mattresses.
Small double and double mattresses
For small double (120cm) and double (140cm) beds, again check whether your bed takes the 190cm or 200cm length:
- Sleeptight Pocket 120 x 190cm (Pink Label) or 120 x 200cm (Orange Label) — £349
- Sleeptight Pocket 140 x 190cm (Gold Label) or 140 x 200cm (Light Green Label) — £375
All are 15cm deep. See our double mattresses.
Why mattress depth matters on raised beds
On bunk beds, high sleepers and mid sleepers, the guard rail is set a fixed height above the mattress. A mattress deeper than the manufacturer's stated maximum reduces that protection, so never exceed the maximum mattress depth shown on the product page. Our Bunk Bed Mattress Guide covers this in detail.
Mattress sizes: common questions
What size mattress does a trundle bed take?
Most take a 90 x 190cm mattress around 10cm deep, so it can slide under the main bed. Check the trundle's size and maximum depth on the product page.
Can I use a normal single mattress on a trundle?
Usually not — a standard single is 14–15cm deep and will normally stop the trundle sliding back under the bed.
What size mattress does a day bed need?
Most day beds take a standard single, either 90 x 190cm or 90 x 200cm. Pull-out guest day beds use slimline 10cm mattresses. A slim daybed mattress gives a more sofa-like seat.
What size is a shorty mattress?
70 x 160cm — shorter and narrower than a standard single.
Is 90 x 200cm the same as a UK single?
No. A UK single is 90 x 190cm. A 90 x 200cm mattress is a continental (European) single, 10cm longer.
How long does a rolled mattress take to expand?
Allow around 24 hours after unpacking for a rolled mattress to expand fully.
Need help?
All our Sleeptight mattresses are made in the UK, and many are rolled for easy delivery. If you're not sure which mattress fits your bed, get in touch with the bed name and we'll tell you exactly what you need. For bed frame sizes, see our Children's Bed Size Guide and Children's Mattress Buying Guide.