King Size Mattress Protectors

A king size bed is where most British couples end up — enough room to share without negotiating territory. Protecting it properly starts with a protector that's actually cut for a UK king: 150 x 200cm, with a deep elasticated skirt that grips the corners and stays smooth under the sheet. Choose quilted for everyday freshness or waterproof for full spill-and-accident cover — both machine washable at 40°C.

Made to Fit a UK King — Properly

"King size" means different things in different countries, which is where badly fitting protectors come from. A UK king mattress measures 150 x 200cm (5ft wide), and every protector on this page is cut to exactly that — not a US king, not a loose one-size-stretches-to-fit. The difference shows up in use: a properly sized protector lies flat with no wrinkles to feel through the sheet, and its elasticated skirt wraps the corners deeply enough that it's still in place on Sunday morning after a week of restless nights.

If your bed is actually the larger 6ft size, you want our super king mattress protectors (180 x 200cm) instead — a king protector stretched over a super king mattress will pull loose within nights. And if you're not sure which you have: measure the mattress width. 150cm is king; 180cm is super king.

Quilted or Waterproof — Your Household Decides

The choice is simple honesty about your bed's life. If it's adults, tea drunk carefully and no pets, a quilted king protector keeps the mattress fresh with a whisper of extra softness. If children climb in at dawn, a dog claims the foot of the bed, or breakfast in bed is a weekend ritual, a waterproof king protector adds a silent liquid-proof membrane beneath the same soft surface. Both wash at 40°C; both fit like a fitted sheet. Undecided between types? Our mattress protectors guide walks through the differences in two minutes.

Worth Protecting

King mattresses are a serious purchase — often £400 to well over £1,000 — and they're the one thing on the bed you can't launder. A protector costs a fraction of that and takes the nightly moisture, dust and everyday accidents so the mattress doesn't have to. It's also the difference between a valid and voided warranty with many mattress brands, who can decline stain-affected claims. Five seconds of fitting; years of mattress life. If a king mattress topper is part of your comfort setup, fit the protector over the topper so both stay protected.

FAQ

What size is a king size mattress protector in the UK?
150 x 200cm — matching the standard UK king mattress (5ft wide). All our king protectors are cut to this exact size with deep elasticated skirts for a secure fit.
Will a king size protector fit a super king mattress?
No — a super king is 30cm wider (180cm vs 150cm). Stretching a king protector over it pulls the corners loose and leaves the edges uncovered. If your mattress measures 180cm across, choose a super king protector.
What's the difference between a double and a king protector?
A UK double is 135 x 190cm; a king is 150 x 200cm — wider and longer. If you've upgraded from a double bed, your old protector won't fit the new mattress; you'll need king size across protector, sheets and bedding.
Do king size protectors fit deep mattresses?
Yes — our elasticated skirts are cut generously to wrap standard and deep king mattresses, including beds wearing a topper underneath. The protector should sit flat and stay put; if corners ping off, the size (not the depth) is usually wrong.
Are king size mattress protectors machine washable?
All of ours are — 40°C wash, low tumble dry, back on the bed the same day. Monthly washing keeps the protector doing its job; waterproof versions handle unlimited accident washes.