Do Twin Bed Frames Expand To Full?

Twin Full Frame

Twin beds serve wonderfully for when space is limited or the person using the bed is small, but often an upgrade is inevitable. To save money and time, people are often interested in whether or not a twin bed frame can expand to full. 

Do twin bed frames expand to full? Most of the time, no. Some bed frames are available that can expand and contract but more often than not a new frame will need to be acquired.

Despite the answer, it is rarely that simple. There is still more info to be had about bed frame sizing and alternative methods of fitting a larger sized mattress into a twin frame. 

Will A Twin Fit A Full?

There are a wide variety of reasons to want to upgrade from a twin to full. Whether it’s because more space has become more available, someone has grown up, or you are looking to expand a bed to fit an extra person, one of the closest in size is a full bed.

Sadly, a twin bed frame will most likely not fit a full-sized mattress. There are some key differences in size that would make this almost impossible. However, there are bed frames that can easily expand to fit a full. If you are buying a new frame and expect to change sizes later, be sure to grab one that can do so. In the worst-case scenarios, there are options to modify a twin bed frame to allow a full bed to fit even when not intended.

To check if your bed frame is expandable, look for signs that the frame can be modified. This will most likely come in the form of:

  • Multiple sockets for supports and bolts (common in wooden frames)
  • Molded areas where the width of the frame can be added upon (common in plastic frames)
  • Pieces of the frame that can be pulled apart and secured at different lengths with wing nuts (common in metal frames)

Each of these methods is meant to be easy to use and provide the best option for allowing a twin bed frame to fit a full mattress.

Twin Beds VS. Full Beds

What are the differences between a twin-sized bed and a full-sized bed? In reality, not much. They share the same length, except the full bed is wider.

A twin bed is 38” wide by 75” long. This is wide enough for one person and great for saving space. If you are looking for a child’s bed, an adult’s bed in a small room, or a guest room, a twin bed may work.

In contrast, a full bed is 54” wide by 75” long. For a long time, a full-mattress was the most common size for couples to sleep in. In recent decades, however, a Queen is a much more normal size. Still, it can fit two people fine. A full-sized bed is recommended for one adult, two adults in a smaller room, or an older child who is expected to grow into the bed. Full beds are highly versatile and a great option.

Because both beds are only 75” long, it can be difficult for a tall adult to fit comfortably. This can be a great boon, however, for switching between twin sized mattresses and full-sized mattresses. If you are interested in expanding into a longer mattress, be sure to buy a bed frame that allows for expansion of size.

Modifying A Twin Bed Frame

If you do not have a bed frame that can be expanded upon but do not want to buy a whole new frame, you may be able to modify what you have. Because a twin bed and a full bed are the same length, the total amount of work to be done to expand into a full is reduced.

The process of modifying a twin frame to allow for a full-sized mattress is fairly straight forward. Simply remove the width of the frame and instead place new supports. However, the details and structure of an individual frame can turn this seemingly easy task into a painful one. Things to note and look out for include:

  • Noting the material of the frame
  • What are the bed frame’s supports?
  • Does the bed have a head or footboard?
  • Is the material changeable?

Each of these are important notes that can heavily modify how difficult the process of modifying a twin to fit a full will be. Depending on the material of the bed frame, it is most likely easier and cheaper to buy a new frame than to modify an existing one. This is especially true for materials such as thick plastics, intricate metalwork, or high-end woods. It is best to leave this as an option only if you are looking to keep a family heirloom or breathe new life into an antique piece.

To modify a bed’s frame, the supports must be removable. Often, a bed frame will be screwed together. So long as the supports are removable, you can modify the bed-frame. However, if your frame is welded together, dovetailed, or molded together, it will be an incredibly difficult process to modify the frame.

Headboards and footboards would also have to be replaced in the process of modifying a bedframe, as they are entirely dependent on the width. As such, platform beds work best for modification.

Finally, you need to be sure you can match the material used in the original bed frame. If not, the bed frame will most likely look bad and lose the original look. This only really becomes an issue with high-end woods or intricately patterned pieces.

Will Two Twin Bed Frames Make A King?

A king-sized bed frame is a large step up from a twin, increasing every dimension. Two twin-sized bed frames together will come close to the size of a king, but not match it. When combined, two twin bed frames will be the same width as a king but not the same length. 

A king-sized mattress is 76” by 80”. Compared to a twin, a king is significantly wider and also gains 5” of length. One twin is 36” by 75”, so even when two are combined the length of the frame will not change.

Combining Two Twins

Combining two twin beds into one is still a great option for utilizing extra beds that will result in a sleeping area still large enough for almost no one to complain about. To do that, simply combine the two twin bed frames and place two twin mattresses on top.

Then, place a “bed bridge” between the two. Bed bridges are pieces of foam or mattress that are meant specifically for this purpose, to cover the split between two mattresses. After this, simply place the covers and sheets on like normal and you are good to go.

For covering the mattresses, king-sized sheets will be a bit large but should do the trick. To help with the fitting, a mattress pad can help size out the difference and make the bed even comfier. 

Using XL Twins to Make A King

There are slight variations of twin beds which could prove useful for making a king. An XL twin shares the same width of 36” as a normal twin, but is lengthened to 80”. Two of these frames together would fit a king perfectly!

XL twins are common in college dorms to save space while still providing the length that tall adults need. It could be possible to gather two that may be being replaced by a nearby college and combine them for a quick pass at a king-sized frame.

With the two frames and two mattresses, simply place them nearby and follow the above steps to make a proper king-sized bed. Normal sheets will work great atop the mattresses and no one should notice the differences.


Hi there! I’m Alex, the one behind this website. I ran and operated a Local Furniture Store in Southern California. The store opened in 2010, during the “Great Recession,” It is still thriving today; however, I have dedicated my time to helping our online customer base. My primary focus is to help you with all your furniture & mattress questions.

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