The simplest way to a beautifully made bed starts with the right measurements. Explore U.S. mattress sizes, fitted-sheet depth, duvet proportions, and pillow dimensions.
The art of a considered bed
Before choosing a size
Measure your mattress.
A bed's name is useful, but the measurements tell the full story. Take three simple measurements before selecting sheets, mattress protection, or a topper.
01 / WIDTH
Side to side
Measure across the mattress at its widest point. This is the first number in a mattress size.
02 / LENGTH
Head to foot
Measure from the head of the mattress to the foot, without including the bed frame.
03 / DEPTH
Top to bottom
Measure the mattress thickness, including any topper used beneath your fitted sheet.
Reference 01 / U.S. sizes
Mattress dimensions.
Common nominal U.S. mattress dimensions, shown width × length in inches. Actual measurements may differ slightly.
Mattress size
Width × length
Typical use
Twin
38 × 75 in
Compact rooms and children's beds
Twin XL
38 × 80 in
Longer single beds and dorm rooms
Full / Double
54 × 75 in
Single sleepers wanting more width
Queen
60 × 80 in
Versatile everyday double sleeping
King
76 × 80 in
Extra width for a spacious bed
California King
72 × 84 in
More length with a slightly narrower width
Split King: two Twin XL mattresses positioned side by side make a combined 76 × 80 in footprint. For adjustable split beds, fitted sheets usually need to fit the two separate Twin XL mattresses. Always check the individual product measurements before ordering.
Reference 02 / Sheets
Find the fitted fit.
Match the fitted sheet's mattress width and length first. Then check its pocket depth: the amount of mattress thickness it is designed to accommodate.
01Fitted sheets: choose the correct mattress footprint and a pocket depth suitable for the measured thickness.
02Flat sheets: consider how much extra fabric you prefer for tucking or draping at the sides and foot.
03Sheet sets: review the stated fitted-sheet, flat-sheet, and pillowcase dimensions; included pieces vary by set.
The details behind the fit
Three things to check.
A little attention to depth and layering makes bedding feel more considered—and helps prevent a fitted sheet from slipping off the corners.
01 / Pocket depth
Allow for thickness.
Choose sheets whose stated mattress-depth fit accommodates the total measured mattress and under-sheet topper height.
02 / Toppers & pads
Match the footprint.
Mattress toppers, pads, and protectors should correspond to your bed's width and length. Check thickness and attachment details separately.
03 / Brand variations
Trust the product listing.
Dimensions, shrinkage allowances, elastic construction, and included pieces differ. The measurements on each product page take priority.
Reference 03 / Top layers
Layer with intention.
Duvet covers, comforters, and quilts do not share one universal dimension for each mattress size. Choose based on the insert or product's listed width and length, plus the amount of drape you prefer.
Duvet coversCheck against your insert's actual dimensions.
ComfortersReview the finished size and desired side drop.
Quilts & blanketsDecide between a neat coverlet fit and generous layering.
King vs. Cal KingDo not assume they use interchangeable fitted bedding.
Reference 04 / Pillow layers
Complete the bed.
Pillowcase sizes are selected to suit the pillow insert, not simply the mattress. Decorative shams may be structured differently from everyday pillowcases.
Standard pillow20 × 26 in
Queen pillow20 × 30 in
King pillow20 × 36 in
Euro square pillow26 × 26 in
Typical U.S. pillow insert dimensions. Pillowcase and sham measurements, closures, and fit allowances may vary by manufacturer.
The final check
Sizing questions.
A few common details worth confirming before choosing your next sheets, duvet, mattress topper, or pillows.
Are King and California King sheets the same?
No. A standard King mattress is approximately 76 × 80 inches, while a California King is approximately 72 × 84 inches. Their fitted sheets are not ordinarily interchangeable.
How do I size sheets for a mattress topper?
Measure the combined thickness of the mattress and any topper placed underneath the fitted sheet. Then choose a fitted-sheet pocket-depth range that accommodates that total.
Does a Queen duvet always have the same measurements?
No. Duvet inserts, duvet covers, comforters, and quilts can vary substantially between brands. Match the actual insert and cover dimensions, rather than relying on the size name alone.
What if my mattress is an unusual size?
Measure its width, length, and height and compare those dimensions with each product's specifications. RV, crib, specialty, and custom mattress sizes may not follow the six standard U.S. dimensions above.
Personal guidance
Still choosing a size?
Our customer care team is available 24/7. Share your mattress measurements and the Somelle product you are considering so we can help you review its listed dimensions.
