A trundle bed is one of the simplest ways to add a second bed without giving up floor space. During the day, the extra mattress hides under the main bed. When a sibling, cousin or friend sleeps over, it rolls out in seconds. Trundles appear under twin beds, daybeds, bunk beds and captain's beds, and they come in several styles—so it helps to know how they work before you shop. This updated Bel Furniture guide explains what a trundle bed is, the main types, sizes and mattress requirements, pros and cons, how trundles compare to daybeds and bunk beds, and how to choose the right one for a kids' room or guest room.
What Is a Trundle Bed?
A trundle bed is a low, pull-out bed frame that stores underneath a main bed. It holds a second mattress, so one bed footprint can sleep two people when needed. The word "trundle" comes from the small wheels, or casters, that let the frame roll in and out.
Trundles are most common under twin beds and twin daybeds, but you will also find them under bunk beds, captain's beds and some full-size beds. They are a favorite for kids' rooms, guest rooms, home offices and any space that needs a bed for occasional sleepovers.
How Does a Trundle Bed Work?
The trundle frame sits on casters or glides under the main bed. To use it, you pull the trundle out by a handle or the front panel, then make it up with its own mattress and bedding. When you are done, you roll it back underneath.
Most trundles sit lower than the main bed, so the two sleepers are at different heights. Pop-up trundles have folding legs that raise the trundle to sit alongside the main bed, creating a wider sleeping surface. Wood trundles typically include slats, so no box spring is needed. For example, the Calinda, Bozeman and Redding twin daybeds at Bel Furniture each include a slatted trundle on four wheels.
What Are the Different Types of Trundle Beds?
| Type | How it works | Best for |
|---|---|---|
| Roll-out trundle | A low frame on casters that rolls out from under the bed | Kids' rooms and sleepovers |
| Pop-up trundle | Folding legs raise the trundle to near the main bed's height | Guest rooms where two adults may want a wider shared surface |
| Storage trundle | A drawer that holds a mattress or doubles as storage | Rooms that need storage most nights and a bed occasionally |
| Daybed with trundle | A sofa-style frame with a trundle underneath | Guest rooms, offices and teen rooms |
| Bunk bed with trundle | A bunk with a pull-out bed under the bottom bunk | Three kids or frequent sleepovers |
| Captain's bed with trundle | A storage bed with drawers and a trundle | Kids' rooms that need storage and an extra bed |
The Chapman wood storage trundle is a good example of a convertible design: it works as a two-section storage drawer or as a trundle bed when you add a mattress. Learn more about drawer beds in our captain's bed guide.
What Size Is a Trundle Bed?
Most trundles hold a twin mattress, about 38 by 75 inches, because the trundle must fit inside the frame of the bed above it. Common combinations include:
- Twin bed with twin trundle: the most common pairing.
- Twin daybed with twin trundle: the classic guest-room choice.
- Full bed with twin trundle: a full frame above, with a twin trundle below.
- Twin-over-twin or full-over-full bunk with twin trundle: sleeps three.
A few designs use a full-size trundle under a full bed. Always confirm the trundle's mattress size and maximum thickness in the product details. For twin dimensions and room sizes, see our twin bed size guide.
What Mattress Do You Need for a Trundle Bed?
Trundle mattresses need to be thinner than a typical main-bed mattress because they must slide under the bed frame. The exact limit depends on the clearance under the main bed, so check the product's specified maximum thickness. Some points to keep in mind:
- Measure clearance. The trundle frame height plus the mattress must fit below the main bed's rails or slats.
- Foam works well. Foam mattresses are lighter and easier to slide in and out.
- Consider a built-in bunkie board. The foam mattress with built-in bunkie board is designed for low-clearance trundle and bunk frames.
- Pop-up trundles may have different thickness requirements, since they rise to the main bed's height.
Shop twin mattresses and kids' mattresses, or add a bunkie board for extra support.
Trundle Bed Pros and Cons
| Pros | Cons |
|---|---|
| Adds a second bed without using extra floor space | Trundle sits lower and can be less comfortable for adults |
| Easy to set up for sleepovers and guests | Needs a thinner mattress |
| No climbing, so it is suitable for younger children | Requires clear floor space to roll out |
| Many designs include slats, so no box spring is needed | Bedding must be stored or kept on the trundle |
| Can double as storage when not used as a bed | Takes away under-bed storage if used only as a bed |
Trundle Bed vs. Daybed vs. Bunk Bed
| Trundle bed | Daybed (with or without trundle) | Bunk bed | |
|---|---|---|---|
| Sleeps | Two, when the trundle is out | One, or two with a trundle | Two, or three with a trundle |
| Daytime use | A standard bed | A sofa or lounge seat | A standard bed |
| Climbing | None | None | Top bunk requires climbing; ages 6 and up |
| Floor space when not in use | Same as one bed | Same as one bed | Same as one bed |
| Best for | Occasional sleepovers | Guest rooms, offices, teen hangouts | Two kids who share full time |
For a detailed comparison that includes sleeper sofas, read Daybed vs. Trundle Bed vs. Sleeper Sofa. For bunk options, see our bunk bed configuration guide.
How Much Room Do You Need for a Trundle Bed?
When the trundle is closed, it uses no extra space. When it is open, you need roughly the width of a twin mattress—about 38 to 40 inches—in front of the bed, plus room to walk around it. A good rule is to leave at least 24 inches of clear walkway beside the open trundle so no one has to climb over a sleeping guest to reach the door.
Before you buy, pull out a tape measure and mark the open trundle's footprint on the floor. Check that a rug, nightstand or dresser drawer will not block it. Our daybed and trundle bed buying guide includes more layout tips.
Are Trundle Beds Good for Kids?
Yes—trundles are one of the most kid-friendly ways to add a bed. There is no ladder to climb, the trundle sits close to the floor and the main bed stays a normal height. That makes trundles a good option when a younger child is not old enough for a top bunk.
A few tips for families:
- Roll the trundle fully in or fully out—never leave it partway open where someone could trip at night.
- If you use a pop-up trundle, make sure the legs lock securely before anyone sleeps on it.
- Store the trundle's bedding in a nearby bin or on the trundle itself so setup takes seconds.
- Use the trundle as storage between sleepovers if the design allows it.
Hosting often? See our bunk beds and sleepovers guide and our shared bedroom ideas.
How to Choose a Trundle Bed
- Decide who will use it. Kids' sleepovers suit a standard roll-out trundle. Adult guests may prefer a pop-up trundle or a daybed.
- Choose the main bed style. Twin bed, daybed, bunk bed or captain's bed.
- Confirm mattress size and thickness for both the main bed and the trundle.
- Measure the open footprint and keep a clear walkway.
- Check the build. Look for slats, smooth casters and a sturdy front panel.
- Match the room. Wood finishes like natural, walnut and cherry suit traditional rooms; upholstered and metal daybeds fit modern spaces.
Shop Trundle Beds at Bel Furniture
Bel Furniture carries twin daybeds with trundles in wood, upholstery and metal, plus bunk beds and captain's beds with trundles. Featured options include the Calinda wood twin daybed with trundle, the Bozeman camelback daybed in medium walnut, the Redding daybed in cherry, the Brodie upholstered daybed, the Carlsbad captain's bed with trundle and the silver twin-over-twin bunk with pull-out trundle. Browse kids' daybeds, all daybeds and bunk beds. Here is why families choose Bel:
- Direct factory pricing with no middleman markup.
- Texas's largest family-owned furniture retailer, serving families since 2000.
- Top 100 U.S. furniture store.
- 16+ showrooms where you can test trundles before you buy.
- Free delivery and setup on qualifying orders of $1,999 or more.
- Wide selection of daybeds, trundles, bunk beds and mattresses.
- Flexible payment with special financing for up to 60 months on approved credit.
Setting up a guest room? Read How to Set Up a Guest Bedroom.
