A mattress size comparison helps you choose the right bed for your room and sleep needs before you buy. Sizes range from Twin (38×75 in) to Cal King (72×84 in), with each option suited to different room dimensions, body types, and sleeping arrangements. Use the visual diagram and room fit calculator below to find the best fit.
Visual Size Comparison
All sizes drawn to scale — click any mattress to highlight it in the table below
Mattress Dimensions & Details
Dimensions in inches| Size | Width | Length | Min Room |
|---|
Room Fit Calculator
Enter your room dimensions to see which sizes fit with comfortable clearance (2 ft sides, 3 ft foot)
Side-by-Side Compare
Select two mattress sizes to compare them directly
How to Use the Mattress Size Comparison Tool
Choosing the wrong mattress size is an expensive mistake. This mattress size comparison tool gives you three ways to find the right size: a visual scaled diagram, a room fit calculator, and a direct head-to-head comparison between any two sizes.
Step 1: Review the Visual Diagram
The diagram at the top of the page shows all seven mattress sizes drawn to the same scale, side by side. Toggle between inches and centimeters using the in/cm button in the header. Click any mattress in the diagram to highlight that row in the reference table. This makes it immediately obvious how much size difference there is between, say, a Queen and a King — the King is 16 inches wider.
Step 2: Check Your Room Dimensions
Enter your bedroom's width and length into the Room Fit Calculator. The tool applies standard clearance guidelines — 2 feet on each side and at the head, 3 feet at the foot — and shows each mattress size as "Fits", "Tight Fit" (under recommended clearance), or "Doesn't Fit". Most 10×10 rooms comfortably fit a Full/Double. A 12×12 room is the practical minimum for a King or Cal King.
Step 3: Compare Two Sizes Directly
Use the Side-by-Side Compare section to pick any two sizes from the dropdowns. The comparison shows dimensions, price range estimates, minimum room requirement, and how much extra sleeping area one size provides over the other. The difference between Queen and King is 1,280 square inches — roughly equivalent to adding an extra pillow's worth of space on each side per person.
Understanding Per-Person Space
The reference table includes a "Sq in / Person" column that divides the total sleeping surface by the number of typical sleepers. A Full/Double gives each of two adults 2,025 sq in (about 40×50 in) — tight for most couples. A Queen gives each person 2,400 sq in (40×60 in), while a King gives 3,040 sq in per person. Solo sleepers get the full surface regardless of size.
Which Size Should You Choose?
Twin or Twin XL — children, single adults in smaller rooms, bunk beds, and dorms. Twin XL adds 5 inches of length for taller individuals. Full/Double — solo adults who want more room to stretch, or couples on a tight budget with a smaller bedroom. Queen — the most popular choice for couples; fits in most standard bedrooms. King — couples who want maximum space, or those who share a bed with a child or pet. Requires a large room. Cal King — best for tall individuals (6'2"+) or rooms that are longer than they are wide. Split King — ideal for couples with different firmness preferences or who use adjustable bases.
FAQ
Is this mattress size comparison tool free?
Yes, this tool is completely free with no signup, no account, and no hidden costs. All calculations and diagrams run entirely in your browser — nothing is sent to any server.
Is my data private when using this tool?
Absolutely. Everything runs locally in your browser using client-side JavaScript. Your room dimensions and preferences never leave your device.
What is the most popular mattress size?
Queen is the most popular mattress size, used by roughly 60% of households. It offers a good balance of sleeping space for couples and fits comfortably in most master bedrooms (10×10 ft minimum). King is the second most popular choice for couples wanting extra space.
What is the difference between King and California King?
A standard King (76×80 in) is wider than a Cal King (72×84 in), but the Cal King is 4 inches longer. King is better for couples who sleep side by side, while Cal King suits taller people over 6'2" or narrower rooms where the extra length is helpful.
What is the difference between Twin and Twin XL?
Twin XL is 5 inches longer than a standard Twin (80 vs 75 inches). Both have the same 38-inch width. Twin XL is the standard size used in most college dorm rooms and is a great choice for taller teens or adults sleeping solo.
How much clearance space should I leave around a mattress?
A commonly recommended rule is to leave at least 2 feet (60 cm) on the sides and at the head of the bed, and 3 feet (90 cm) at the foot for comfortable passage. The room fit calculator in this tool uses these guidelines to determine if a mattress fits your room.
What is a Split King mattress?
A Split King consists of two Twin XL mattresses placed side by side, totalling the same dimensions as a standard King (76×80 in). It allows each partner to have their own mattress with independent firmness settings — essential for adjustable bases where each side moves independently.
What is the minimum room size for a King bed?
A King mattress (76×80 in) requires a minimum room size of about 12×12 feet to allow comfortable movement around the bed with standard clearance. Ideally, a 13×13 ft or larger room gives the best result. Cal King has the same minimum room recommendation.