King Size Mattress

King Mattress Dimensions: How Big Is a King Bed?

A standard king mattress measures 183cm wide x 203cm long, which is 30cm wider than a queen. This extra width means each person gets roughly the space of a king single to themselves. Once you’ve slept in one, a queen starts to feel a little cosy. You'll want a bedroom of at least 12m² to make it work comfortably but you can check our bed size guide to compare sizes and find the best fit for your room. 

Is a King Mattress Right for You?

A king size mattress suits more sleepers than you might think, and the right one can genuinely transform how you feel every morning. Think deeper sleep, more energy, better focus, and waking up without that stiff, groggy feeling that follows you into the day. Here is who gets the most out of one:

For Couples

More space means less compromise and better sleep for both of you. Whether you're a restless sleeper, run hot, or simply want to stop elbowing each other at 2am, a king mattress for couples makes a real difference. And if you and your partner prefer different firmness levels, the MySide Mattress, exclusive to Forty Winks, offers a different feel on each side. Two personalised support options, one mattress, and two people waking up actually refreshed. 

For Solo Sleepers

Sometimes you just want to sprawl out completely, and a king mattress gives solo sleepers a genuinely luxurious sleep experience with room to shift position through the night without ever feeling like you're running out of space. Wake up feeling energised and ready to take on whatever the day throws at you.

For Families

A king bed is a fit for a king, or for those cosy weekend mornings when the whole family piles in, kids, pets and all. The extra width means everyone gets a spot without someone ending up on the floor, and you actually get to enjoy it rather than cling to the edge. 

How to Choose a King Mattress: Firmness Guide

Firmness is one of the most important decisions you'll make when choosing a king size mattress, and getting it right is the difference between waking up energised and waking up sore. Here's a quick guide on the levels we stock at Forty Winks:

Ultra Plush

If your idea of perfect sleep involves sinking into something that feels like a cloud, ultra plush mattresses were made for you. The softest feel in the range, with deep cushioning comfort layers that cradle every curve of your body and take the pressure off completely. Best suited to side sleepers who want maximum pressure relief and that blissful, wrapped-in feeling from the moment they lie down. 

Plush

All the support you love, with a little extra luxury. Plush mattresses give side sleepers that contouring, close feel without the sensation of sinking too deeply, so you wake up feeling genuinely cradled rather than swallowed up. The sweet spot between soft and seriously inviting. 

Medium

Can't decide? Medium is where most people land, and for good reason. The most versatile comfort level in the range, a medium king mattress works brilliantly for combination sleepers and couples who can't quite agree, balancing comfort and support so everyone wakes up feeling their best. A brilliant starting point if you are still working out your preference. 

Firm

If you prefer a sleep surface that feels steady and dependable, firm could be your perfect match. A king mattress firm option offers a more structured feel with less cushioning and sink, making it a popular choice for back and stomach sleepers. It's ideal for those who enjoy a mattress that feels stable from the moment they lie down to the moment they wake up.

Ultra Firm

Ultra firm is for sleepers who want as little sink and softness as possible. A king mattress ultra firm provides a consistently level sleep surface that feels solid from edge to edge. If plush and pillow-top mattresses have never been your thing, this is the firmness level that delivers a straightforward, no-fuss sleep experience night after night.

King Mattress Brands at Forty Winks

Every brand we stock has earned its place. Discover our selected range of leading international and Australian mattress brands, including Sealy, King Koil, Tempur, Silent Partner, Crown Posture Bedding, MySide, MLILY, and Active Sleep. 

Whether you're after an APA-endorsed design for back support, a luxury memory foam king mattress, or an exclusive split-comfort option, we have the brand to match. 

Our sleep advisors know each range inside out and are there to help you find the king mattress that works for you, not just the one that sounds best on paper. 

Not Sure Which King Mattress to Choose? Try bedMATCH

Choosing the right king mattress from hundreds of options is no small task, which is exactly why we built something to make it easier. As a proudly Australian, family-owned retailer with stores nationwide and decades of sleep expertise behind us, we created bedMATCH exclusively for Forty Winks customers. This clinically proven sleep diagnostic system takes 18 precise body measurements and runs over 1,000 calculations to pinpoint the right level of support for your body and sleep style. It works for couples too, so both of you walk out confident. Because when the mattress is right, everything feels different. More energy, better mornings, and the kind of sleep that actually restores you. Find your nearest Forty Winks store and get your bedMATCH today.