King Mattress

A king size mattress suits more sleepers than you might think, giving you more room to stretch out, sleep deeper and wake up with more energy. Couples get more space to move without disturbing each other through the night, solo sleepers can spread out and stay comfortable, and it's roomy enough for the whole family to pile in for a lazy Sunday morning. Whether you're upgrading from a queen or simply want more room to sleep, a king mattress makes the difference you'll notice every morning.

What size is a king mattress?

A standard Australian king mattress measures 183cm wide by 203cm long (1830mm x 2030mm).

The second biggest mattress size Forty Winks offers, a king mattress is 30cm wider than a queen mattress but the same length, giving each person an additional 15cm of sleeping space. Compared to a super king mattress, a king is 20cm narrower and the same length.

That extra width means more sleeping space, but it also requires more room. As a general guide, aim for at least 60cm of clearance around accessible sides of the bed so you can move comfortably. Remember to account for bedside tables, wardrobes, door openings, and the external dimensions of your bed frame.

Not sure whether a king is the right fit? Explore our bed size guide to compare Australian mattress sizes and dimensions.

Who is a king mattress best for?

A king mattress is ideal for couples who love having their own space when it’s time for sleep.

At 183cm wide, the king gives each sleeper approximately 91.5cm of sleep space. That’s almost the width of a single bed, so couples can move without disturbing each other. It's also a practical option for families with little ones or pets who occasionally join them in bed, or solo sleepers who simply enjoy having extra space.

Keep in mind that a king mattress is the same length as a queen, so the main benefit is additional width. If you've got the bedroom space and prefer a little more room between sleepers, a king could be the right fit.

How do I choose the right king mattress?

Choosing a king mattress is about more than finding the right size. It's about finding the right balance of comfort and support for your individual sleep needs.

Comfort is how a mattress feels when you lie down, while support is how well it helps maintain your body's natural alignment as you sleep. And because everyone's different, there's no one-size-fits-all solution.

That's where Forty Winks bedMATCH® comes in. Our exclusive, science-backed mattress matching technology helps take the guesswork out of choosing a mattress suited to your body and sleep needs. Visit your local Forty Winks store to experience bedMATCH® and get personalised guidance from our Sleep Advisors. They'll help you explore your options and find a king mattress that feels right for you.

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, MLILY, and Active Sleep.

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

Our trusted 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.

More about choosing a king mattress

King vs queen mattress size

Thirty centimetres might not sound like much, but when it comes to sleep it is a game changer. A king mattress measures 183cm x 203cm, giving each partner roughly the same sleeping space as a king single bed to themselves. If your bedroom is 12m² or more, a king mattress for couples is the upgrade most people never go back from. Consider yourself warned.

Best king mattress for couples

Whether you and your partner agree on how a bed should feel makes all the difference, and let's be honest, most couples don't. For couples who share similar preferences, Silent Partner and King Koil Chiro are both excellent choices, delivering strong motion isolation so a restless sleeper on one side stays on that side. If you and your partner need different levels of support, a Forty Winks bedMATCH^® consultation in-store can help you find options that work for both of you.

Best king mattress for back pain

If you are waking up stiff and sore, your mattress is not doing its job. The King Koil Chiro Clarity and Crown Posture Bedding ranges are both designed with spinal alignment front of mind. For a truly personalised recommendation, a free Forty Winks bedMATCH^® consultation in store uses science to find the best mattress for you.

Room size for a king mattress

A minimum of 12m² is the starting point, with a room of at least 3.5m x 3.5m being the ideal. That gives you space for bedside tables and easy movement around the bed without feeling like the mattress has taken over. Not sure if your room measures up? Our bed size guide has layout tips to help you figure it out before you commit.

King mattress prices in Australia

The cost of a king mattress at Forty Winks ranges from around $499 for entry-level through to $12,999+ for luxury options. When you consider you will use it every night for 8 to 10 years, it works out to very little per night for a genuine improvement to your sleep and your days. Finance options make upgrading more accessible, and Quick Ship delivery is available on selected models in metro areas.

What bed fits a king mattress?

A king mattress is designed to fit a compatible king-sized bed base or bed frame. Choosing the right foundation is important for supporting your mattress and ensuring it performs as intended.

At Forty Winks, you'll find a range of king bed bases and king bed frames to suit your bedroom and lifestyle. Need extra storage? A gas lift or drawer storage bed can help make the most of your bedroom space. After something with a little more character? Explore upholstered, timber, and contemporary bed frame designs.

Before choosing, check the external dimensions of your bed frame, the available space in your bedroom, and your mattress manufacturer's support requirements to ensure everything fits together.

Next day delivery on king mattresses

It's easier than you think, we offer king mattress next day delivery through Quick Ship on selected in-stock models across Sydney, Melbourne, Perth, and Brisbane metro areas. Orders need to be placed before 4pm Monday to Thursday to qualify for next business day. Standard delivery is available nationwide, with time frames varying by location.