Three Quarter Bed Size: Dimensions, Fit & Options
A three quarter bed measures about 48" x 75" — wider than a twin, narrower than a full, and no longer manufactured. Here are the exact dimensions, how to measure your frame, and the three realistic options for getting a mattress that fits.
A three quarter bed measures roughly 48 inches wide by 75 inches long — about 10 inches wider than a twin and 6 inches narrower than a full. It is an obsolete size. Mattress manufacturers stopped producing it decades ago, so if you own a three quarter bed frame, you are shopping for either a custom-made mattress or a plan to work around the frame. This guide covers the exact dimensions, how to measure your frame correctly, and the three realistic options you have.
Three quarter bed size vs. standard mattress sizes
Here is how the three quarter size compares to the mattress sizes still in production today:
| Size | Width | Length |
|---|---|---|
| Twin | 38" | 75" |
| Twin XL | 38" | 80" |
| Three quarter | 48" | 75" |
| Full | 54" | 75" |
| Queen | 60" | 80" |
The name comes from the proportion: at 48 inches, it is roughly three quarters the width of a 60-inch queen. You may also see it written as a "3/4 bed" or a "three quarter double."
The 48" x 75" figure is a starting point, not a guarantee
This is the single most important thing to understand before you buy anything. Three quarter beds were built largely in the Victorian and early-twentieth-century eras, before the mattress industry standardized sizes. Frames were made by individual furniture makers to their own specifications.
So while 48" x 75" is the most commonly cited three quarter bed size, you will also find frames built for 48" x 72", and plenty that land an inch or two off in either direction. Never order a mattress based on the label "three quarter." Measure the frame you actually own.
How to measure a three quarter bed frame
You are measuring the opening the mattress has to drop into, not the outside of the headboard. Work from the inside edges of the rails.
- Measure the width at the inside of the side rails, at the head, middle, and foot of the bed. Old frames warp. Use the smallest of the three numbers.
- Measure the length from the inside of the headboard rail to the inside of the footboard rail, again taking the smallest reading.
- Measure the height of the side rails from the mattress support surface up to the top edge of the rail. This tells you how thick a mattress you can use before it sits awkwardly above the frame.
- Check the corners. Many antique frames have corner posts that intrude into the sleeping area. A mattress may need notched corners to fit, which is a custom-only job.
- Check the support surface. Slats, a wire spring, or a rope lattice all behave differently. Modern foam and hybrid mattresses need a flat, firm, evenly spaced surface underneath them.
Write all five numbers down before you contact anyone about a mattress. A custom mattress maker will ask for every one of them.
Your three options for a three quarter bed
Option 1: Order a custom mattress
Specialty manufacturers build mattresses to order in non-standard dimensions, including three quarter sizes and frames with notched corners. This is the only route that preserves the frame exactly as it is.
The trade-offs are real, though. Custom mattresses cost more than comparable standard sizes, lead times run weeks rather than days, and they are generally final sale — you will not get the sleep trial, easy exchange, or return window that comes with a standard mattress. You are also limited to whatever constructions that particular maker offers.
Option 2: Put a twin or twin XL in the frame
A twin mattress is 38" x 75", which is the same length as a three quarter bed and 10 inches narrower. It will drop into the frame and the length will be right. You will have a 10-inch gap across the width.
Some people fill that gap with a bolster or a foam strip along one rail and are perfectly happy, especially for a guest room or a child's room. Others find the mattress shifts around and the gap is a nuisance. If your frame measures closer to 72 inches long, note that a twin will overhang; check your length measurement first.
This is the cheapest option by a wide margin and the only one that lets you buy a mattress with a normal trial period and warranty.
Option 3: Retire the frame and move up to a full
A full mattress is 54" x 75" — the same length as a three quarter, 6 inches wider. For most people this is the honest answer. A full gives one adult noticeably more room than a three quarter did, fits a standard bed frame, and opens up the entire market of mattresses, sheets, protectors, and foundations.
Antique three quarter frames are often beautiful, and plenty of people keep the headboard, mount it on a modern full-size frame, and retire the rails. That gets you the look without the sizing problem.
Sheets and bedding for a three quarter bed
Three quarter sheet sets are not stocked by mainstream bedding brands. A handful of specialty sellers make them, and some people have them sewn.
The common workaround is to buy full-size sheets and accept the extra fabric. A full flat sheet works fine. A full fitted sheet will be loose across a 48-inch mattress, though deep pockets and sheet straps or suspenders under the mattress hold it reasonably well. Twin sheets will be too narrow to tuck properly, so size up rather than down.
Is a three quarter bed worth keeping?
Keep it if the frame has genuine sentimental or antique value to you and you are willing to pay for a custom mattress, or if it is going in a guest room that gets used a few nights a year and a twin with a gap is good enough.
Replace it if this is a bed someone sleeps in every night. The cost of a custom mattress, the lack of a trial period, and the bedding hassle add up quickly, and 48 inches is a tight width for an adult who wants to spread out. Moving to a full or a standard size solves all three problems at once.
Frequently asked questions
What size is a three quarter bed in cm?
A 48" x 75" three quarter bed is approximately 122 cm x 191 cm.
Is a three quarter bed the same as a small double?
They are close but not identical. "Small double" is a UK size, typically 48" x 75" (120 cm x 190 cm), which happens to match the common US three quarter dimensions closely. UK small double bedding will often fit a three quarter bed better than US sizes will, but check your own measurements before ordering.
Can I use a twin XL on a three quarter frame?
Usually not. A twin XL is 80 inches long, which is 5 inches longer than a standard three quarter frame. It will not fit between the headboard and footboard. Stick with a regular twin at 75 inches.
Why did three quarter beds stop being made?
The mattress industry consolidated around standard sizes in the mid-twentieth century — twin, full, queen, and king. The queen in particular took over the space the three quarter had occupied for couples, and the twin covered single sleepers. The three quarter fell between the two and was phased out.
Do mattress stores carry three quarter mattresses?
Mainstream mattress retailers do not stock them, because the major manufacturers do not produce them. Three quarter mattresses come from custom and specialty makers who build to your measurements.
Not sure which way to go? Come measure it out
If you are weighing a custom three quarter mattress against moving up to a twin or a full, the easiest way to decide is to lie on both and see how the width actually feels. Our Glendale showroom has twin, full, and queen mattresses set up across a range of firmness levels, and we are happy to talk through your frame measurements with you — including telling you honestly when keeping the antique frame is the better call.
Every standard-size mattress we sell comes with a 120-night sleep trial, and we offer free delivery and setup across the Los Angeles area. Browse our full mattress selection online, or stop by the showroom and bring your measurements.