Can I use regular king sheets on a split king adjustable bed?

You should not use a regular king fitted sheet on a split king adjustable bed. A king fitted sheet is designed for one continuous mattress, and it will pop off as soon as one side adjusts. Instead, use two Twin XL fitted sheets — one for each mattress. You can, however, use a king flat sheet (top sheet) across both mattresses if you prefer.

What size sheets do I need for a split king adjustable bed?

You need two Twin XL fitted sheets (38" x 80") — one for each side. For the top sheet, you can use either two Twin XL flat sheets (for independent movement) or one king flat sheet (for a unified look). If you use a king flat sheet, tuck it loosely so it doesn't pull when one side adjusts.

Why do my sheets keep sliding off my adjustable bed?

Sheets slide off adjustable beds because the mattress bends when you raise the head or feet, creating tension that pulls the sheet corners loose. The fix: use deep-pocket fitted sheets (at least 16 inches), choose stretchy materials like jersey cotton or bamboo, and add sheet straps or suspenders to lock the corners in place.

Do I need special sheets for a split king adjustable bed?

You don't need specialty "adjustable bed sheets," but you do need the right size (Twin XL fitted) and the right features. Look for deep pockets (16"+ to accommodate mattress flex), stretchy fabric (jersey knit, bamboo, or microfiber with spandex), and elastic that goes all the way around — not just the corners. These features prevent the sheet from popping off when the bed adjusts.

How do I keep the gap between split king mattresses covered?

Use a king flat sheet or king duvet/comforter on top — it drapes over both mattresses and hides the center gap. For the fitted sheets, you'll still need two separate Twin XL sheets. If the gap itself bothers you, a bed bridge (foam gap filler) placed between the mattresses creates a smooth surface before you put the top sheet on.

How to Put Sheets on a Split King Adjustable Bed

A split king adjustable bed uses two separate Twin XL mattresses — so sheeting it works differently than a regular king. Here's exactly what sheets to buy, how to put them on, and how to keep them from slipping off.

By The ABL Team|Last Updated: February 28, 2026|6 min read

Quick Answer

Use two Twin XL fitted sheets (one per mattress) + one king flat sheet or comforter on top. Do NOT use a king fitted sheet — it will pop off as soon as either side adjusts.

What Sheets Do You Need for a Split King?

A split king is two Twin XL mattresses (38" x 80" each) placed side by side to form a king-size surface (76" x 80"). Each mattress moves independently, which means each side needs its own fitted sheet.

Sheet Type	Size to Buy	Quantity
Fitted sheet	Twin XL (38" x 80")	2
Flat sheet (top sheet)	King (108" x 102")	1
Pillowcases	Standard or King	2–4

Shopping tip: Look for "split king sheet sets" — they come with two Twin XL fitted sheets, one king flat sheet, and pillowcases in one package. This is usually cheaper than buying pieces separately. See our best sheets for adjustable beds picks.

Step-by-Step: Putting Sheets on a Split King Adjustable Bed

Lay the Bed Flat

Use your remote to lower both sides to the completely flat position. It's much harder to get a snug fit if the head or feet are raised. Also push the two bases together so there's no gap between them.

Put the First Twin XL Fitted Sheet On

Start with one side. Place the fitted sheet over the mattress and tuck the corner with the tag at the bottom-right. Pull the elastic over all four corners, making sure the sheet sits flat with no bunching.

Tip: Most fitted sheets have a tag on the bottom-right or a "long side" label — use this to orient the sheet correctly on the first try.

Repeat on the Other Side

Put the second Twin XL fitted sheet on the other mattress the same way. Make sure both sheets are pulled tight and smooth. The edges where the two mattresses meet should have the sheet tucked neatly underneath.

Add the King Flat Sheet

Drape a single king-size flat sheet across both mattresses. The top edge should line up with the head of the bed. Let it hang evenly on both sides. Tuck the bottom under the foot of the mattresses — but keep it loose enough that it won't pull tight when one side raises.

Alternative: If you and your partner adjust independently a lot, use two separate Twin XL flat sheets instead. Less elegant, but more practical.

Add Comforter and Pillows

Place a king-size comforter or duvet on top. This covers the center seam and makes the bed look like a normal king. Add your pillows, and you're done.

5 Tips to Keep Sheets From Slipping Off

The biggest complaint about adjustable beds is sheets coming loose. When the head or feet raise, the mattress bends and creates tension that pulls sheet corners free. Here's how to prevent it:

Buy deep-pocket sheets (16"+ depth)

Standard 12" pockets aren't deep enough. When the mattress bends, it effectively becomes "thicker" at the hinge point. Deep pockets give the sheet enough slack to stay tucked.

Choose stretchy fabric

Jersey cotton, bamboo, and microfiber with spandex stretch with the mattress instead of fighting it. Crisp percale cotton looks great but has zero stretch — not ideal for adjustable beds.

Use sheet straps or suspenders

Criss-cross sheet straps clip to each corner underneath the mattress and hold the fitted sheet in place. They cost $8–$15 and make a huge difference — especially on thicker mattresses.

Look for all-around elastic

Cheap sheets only have elastic at the four corners. Better sheets run the elastic band all the way around the perimeter, which distributes tension evenly and grips the entire edge of the mattress.

Lay the bed flat before making it

Always return the bed to flat position before putting sheets on. Trying to sheet a bed with the head raised guarantees a poor fit and wrinkles.

Common Mistakes to Avoid

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Using a king fitted sheet on both mattresses. This is the #1 mistake. A king fitted sheet is meant for one 76"-wide mattress, not two 38" mattresses. It will come off immediately when either side adjusts.

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Buying regular Twin instead of Twin XL. A regular Twin is 75" long; Twin XL is 80". The 5-inch difference means a regular Twin sheet will be too short and constantly pop off the foot end.

✗

Tucking the flat sheet too tight. Leave enough slack so the flat sheet can "give" when one side raises. Hospital corners look nice, but they'll pull the sheet off the opposite side when the bed moves.

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Ignoring pocket depth. If your mattress is 12" thick, a 12"-pocket sheet has zero margin. When the bed bends, the corners pop off. Always go at least 4" deeper than your mattress thickness.

Split King vs Regular King Sheets: What's the Difference?

	Split King	Regular King
Fitted sheets	2 × Twin XL	1 × King
Flat sheet	1 × King	1 × King
Each side adjusts?	Yes	No
Sheets slip off?	Rarely (with right sheets)	More often (one big sheet)
Sheet sets available?	Yes — "Split King" sets	Standard king sets

The only real difference is the fitted sheets. Everything else — flat sheet, comforter, duvet cover, pillowcases — uses standard king sizing.

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The ABL Team

Sleep Health Researchers

Our team spends hundreds of hours testing adjustable beds, analyzing specifications, and comparing real-world performance so you can make an informed decision.

Last Updated: February 28, 2026

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