by Our Pick
Saatva Waterproof Mattress Protector. From $175
365-night trial · Lifetime warranty
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A king mattress protector measures 76 x 80 inches with deep pocket fit (14-18" typical) for today's thicker king mattresses. A quality waterproof protector extends mattress life 2-3x by blocking sweat, body oils, dust mites, allergens, and accidental spills. Most premium king mattresses (Saatva, PlushBeds, etc.) actually require a protector to maintain warranty. Here is the complete guide.
King Mattress Protector Dimensions
| Spec | Standard |
|---|---|
| Width | 76 inches |
| Length | 80 inches |
| Standard pocket depth | 14-18 inches |
| Deep pocket depth | 18-22 inches (for luxury thick mattresses) |
Why You Need a King Mattress Protector
- Mattress lifespan 2-3x extended. Protector absorbs what would otherwise reach mattress core.
- Warranty preservation. Most premium king mattresses require protector for warranty validity.
- Dust mite & allergen blocker. Encasement-style protectors eliminate mite habitat.
- Stain prevention. Sweat, spills, drool, body oils all blocked from mattress.
- Allergy relief. Reduces allergen exposure by 80-90%.
- Hygiene. Washable cover on every side of the mattress.
Protector Types
Fitted Protector (Most Common)
Covers top and sides of mattress, elastic corners. Easy on/off. 85-95% of buyers choose this.
Encasement (Full Coverage)
Zippered envelope covering ALL six sides of the mattress. Best for bed bug and dust mite protection. Harder to wash.
Mattress Pad (Cushioning + Protection)
Thicker than a simple protector, adds cushioning. Less watertight than a pure protector. Useful if mattress feels too firm.
Material Options
| Material | Waterproof | Noise | Feel |
|---|---|---|---|
| Cotton + TPU laminate | Excellent | Minimal | Soft, breathable |
| Vinyl (old-style) | Good | Crinkly | Plastic, uncomfortable |
| Polyurethane | Excellent | Silent | Very soft |
| Bamboo + TPU | Excellent | Silent | Very soft, cooling |
Our Top Pick: Saatva Waterproof Mattress Protector
Polyurethane membrane with organic cotton top. Silent, soft, fully waterproof. Fits king mattresses up to 17" thick. Machine washable. 3-year warranty. Compatible with Saatva Classic and most competitors.
Our Pick
Saatva Waterproof Mattress Protector. From $175
365-night trial · Lifetime warranty
Care Instructions
- Wash every 2-4 weeks
- Cold water, gentle cycle
- Unscented detergent
- Tumble dry low or air dry
- Never bleach (damages TPU)
- Never fabric softener (reduces absorbency)
- Replace every 2-3 years
FAQ
What size is a king mattress protector?
76 x 80 inches. Deep pocket 14-18" for most king mattresses; 18-22" for luxury thick mattresses.
Do I need a mattress protector for a king mattress?
Strongly recommended. Most premium mattresses require it for warranty. Extends mattress life 2-3x.
How often should I wash a mattress protector?
Every 2-4 weeks. Weekly if you sweat heavily or have pets.
Does a protector make the mattress hot?
Modern TPU laminate protectors are breathable. Old vinyl trapped heat.
Related reading: Best Waterproof Mattress Pad | Waterproof Pillow Protector | Best King Mattress | King Size Mattress Guide
Related buying tips
Before making a purchase in this category, consider these essentials we recommend checking:
- Trial period — 100 nights minimum, 365 nights ideal for a major mattress or bedding purchase.
- Warranty — 10 years or longer for mattresses; 1-3 years for most bedding accessories.
- Return policy — ensure free returns are included, not store credit only.
- Certifications — CertiPUR-US for foam (no harmful chemicals), GOLS/GOTS for organic latex and cotton, OEKO-TEX Standard 100 for fabrics.
- Shipping — check if white-glove setup and old-mattress removal are included or cost extra.
For our complete shopping framework, see our 2026 best mattress buying guide.