King Mattress Dimensions Chart: Everything You Need to Know

Buying a king size mattress? You need the exact dimensions — not a guess.

This guide gives you a complete king mattress dimensions chart, every size comparison, and tells you exactly which size fits your room and lifestyle.

Standard King Mattress Dimensions in the USA

A standard king size mattress in the USA measures 76 inches wide × 80 inches long (193 cm × 203 cm).

It is the widest standard mattress sold in American stores. According to the Sleep Foundation, a king gives each sleeper roughly 38 inches of personal space — more than a full Twin bed.

King vs California King Size — What’s the Real Difference?

Both are large — but shaped differently. A standard king is wider. A California king is longer.

The California king dimensions are 72 inches wide × 84 inches long. It is 4 inches narrower but 4 inches longer. It is designed for tall sleepers over 6 feet 2 inches who need extra legroom.

King Mattress Dimensions in Inches, Feet & Centimeters

King Mattress Dimensions Chart (All Sizes Compared)

Before choosing a king, see how it stacks up against every other standard mattress size in the USA.

Who Should Choose a King Size Mattress?

A king bed is not just about luxury — it solves real sleep problems. Couples who disturb each other at night benefit the most from the extra sleeping surface area.

King Mattress Size vs Other Bed Sizes — Key Differences

Understanding king bed dimensions is clearest when compared side by side. Here are the two most important comparisons every buyer needs.

How to Choose the Right King Size Mattress for Your Bedroom

Buying a king mattress is a long-term investment. Most quality mattresses last 7 to 10 years. Getting the size right from the start saves money and frustration later.

King Mattress Thickness — Does It Matter?

Yes. Mattress thickness — also called mattress height or profile — directly affects comfort, support, and ease of getting in and out of bed.

Conclusion

Choosing the right king mattress size comes down to three things: your room size, your height, and how you sleep.

Want maximum width? Go standard king (76 × 80 in). Over 6 feet 2 inches tall? Go California king (72 × 84 in).

Always measure your room first. Get the dimensions right — and you will sleep better for the next decade.

FAQs

What are the dimensions of a king mattress?

A standard king mattress in the USA measures 76 inches wide by 80 inches long (193 × 203 cm). It is the widest standard mattress size available, giving each sleeper about 38 inches of personal space.

What size bed is 180×200 cm?

A 180 × 200 cm mattress (roughly 71″ × 79″) is closest to a standard king in international markets, often called a European king. In the USA, it falls just slightly under the standard 76 × 80 inch king dimensions.

Is 6 by 7 king size?

Yes. A 6 × 7 foot mattress (72″ × 84″) matches the exact dimensions of a California king size mattress. It is the longer, narrower king variant — not the standard king.

Is 200cm by 200cm king size?

A 200 × 200 cm mattress (roughly 79″ × 79″) is larger than a standard US king. It is often called a Super King or Emperor size in international markets. In New Zealand, Sealy offers a California king at this measurement as a market-specific variation.

What is the biggest size mattress?

The largest commercially available mattress in the USA is the Alaskan King at 108 × 108 inches (9 × 9 feet). Among standard retail sizes, the California king is the longest at 84 inches, while the standard king is the widest at 76 inches.

How much size is king size?

A king size mattress measures 76 inches wide × 80 inches long, covering 6,080 square inches of total sleeping surface. That equals roughly 6 feet 4 inches wide and 6 feet 8 inches long.