King Size Mattress in CM: Dimensions, Room Fit, and Buying Guide

If you're considering a king size mattress, the first practical question is almost always the same: will it actually fit? Not just in the room, but comfortably — with space to move around, open wardrobe doors, and not feel like the bed has swallowed the entire floor.

Getting the dimensions right before you buy saves a significant amount of hassle. Here's everything you need to know about king size mattress measurements in cm, how they compare to other sizes, and how to work out whether a king is the right choice for your home.

 

King Size Mattress Dimensions in CM

A standard king size mattress measures approximately 183 cm wide by 190 cm long.

These are the dimensions you'll find across most mattress brands in Singapore. That said, it's always worth confirming the exact measurements with the specific brand you're buying from, as there can be slight variations — even a centimetre or two makes a difference when you're matching a mattress to a bed frame.

For reference, here's how the king sits alongside the other standard mattress sizes:

The king and super king share the same width — 183 cm — but the super king is 10 cm longer. That extra length is the main reason taller sleepers sometimes opt for a super king over a standard king.

 

How Much Room Does a King Size Mattress Actually Need?

Knowing the mattress dimensions in cm is only part of the picture. The more useful question is how much floor space the overall setup requires — mattress, bed frame, and comfortable clearance around it.

As a practical guide:

• Sides of the bed: Allow at least 60–70 cm on each side for comfortable movement — getting in and out, making the bed, opening bedside table drawers.

• Foot of the bed: Allow at least 90 cm between the end of the mattress and the wall or wardrobe, so the room doesn't feel closed off.

• Bed frame: Most king size frames add a few centimetres to the overall footprint. Confirm the frame dimensions separately from the mattress dimensions.

Working from the king size mattress dimensions of 183 × 190 cm, a room that comfortably accommodates a king with adequate clearance on all sides typically needs to be at least 400 cm wide and 380 cm long — though layout, door placement, and furniture arrangement all affect this in practice.

The most reliable approach is to mark out the mattress footprint on your bedroom floor using masking tape before you commit. It takes five minutes and gives you a much clearer sense of how a king will actually feel in the room.

 

Is a King Size Right for Your Home?

The dimensions tell you whether a king fits. Your sleep situation tells you whether it's the right choice.

For couples A king size mattress gives two adults generous room to sleep without encroaching on each other's space. The extra width compared to a queen — around 31 cm — is noticeable, particularly for couples where one or both partners move around during the night or tend to sleep with arms and legs extended.

For taller sleepers At 190 cm long, a standard king suits most adults comfortably. If you're above 185 cm, the super king's additional 10 cm of length is worth considering.

For families with young children If a young child occasionally joins you in bed, a king provides enough room to accommodate this without anyone feeling squeezed. It's a practical consideration that many parents overlook when sizing up.

For those who simply sleep better with more space Some people are naturally more comfortable with room to move. If you've ever woken up clinging to the edge of a smaller mattress, a king size is likely to make a noticeable difference to your night.

Browse the Somnuz mattress collection to explore king size options designed for comfort in Singapore's climate — breathability and motion control are worth prioritising alongside size.

 

King Size Mattress Fit by Singapore Home Type

Room sizes vary considerably across Singapore's different housing types, and this affects whether a king is a comfortable fit or a tight squeeze.

HDB flats Standard HDB master bedrooms range roughly from 10 to 14 square metres depending on the flat type. A king size mattress can fit in many of these rooms, but clearance can become limited — particularly in older or smaller flat types. Measure carefully, and consider whether you'd still be able to move comfortably around the room with the bed in place.

Condos Master bedroom sizes in condos vary widely depending on the development, unit type, and floor plan. Some condo master bedrooms accommodate a king with ease; others are closer in size to an HDB room and suit a queen better. Always measure your specific room rather than assuming.

Landed homes Larger bedrooms in landed properties generally accommodate a king size mattress comfortably, with room to spare for bedside furniture and wardrobe access. Super king sizes are also more practical in these settings.

If you'd like guidance specific to your room and situation, our team at the Somnuz mattress showroom in Singapore is happy to help you work through it in person.

 

King Size Mattress and Bed Frame: Getting the Match Right

A king size mattress at 183 × 190 cm needs a king size bed frame with matching internal dimensions. This sounds straightforward, but there are a few things worth confirming:

Internal vs external frame dimensions The external dimensions of a bed frame are always larger than the mattress it holds. When measuring your room, use the frame's external dimensions — not the mattress dimensions — to understand the true footprint.

Slat spacing and support A king size mattress needs adequate support across its full width. If you're buying a frame separately, check that the slat spacing is appropriate for the mattress type — particularly for foam mattresses, which generally need closer slat spacing than spring mattresses.

Headboard depth If the frame includes a headboard, factor in its depth when calculating the distance between the bed and the wall behind it.

Buying the mattress and frame together, or confirming exact dimensions carefully when buying separately, avoids the frustrating situation of a mattress that doesn't quite sit correctly in its frame.

 

What to Look for in a King Size Mattress Beyond the Dimensions

Once you've confirmed the dimensions work for your room, the next step is finding a king size mattress that suits how you actually sleep.

Motion isolation For couples sharing a king, good motion isolation means that when one person moves during the night, the other doesn't feel it. This is particularly worth prioritising if one partner is a lighter sleeper or has different sleep and wake times.

Breathability Singapore's humidity makes airflow through the mattress more important than in cooler climates. A mattress with breathable materials and good ventilation keeps the sleep surface cooler through the night — something that has a genuine impact on sleep quality.

Edge support A king size mattress with good edge support feels stable and usable across its full width. Without it, the sides can feel soft and unsupportive, which effectively reduces the usable sleep surface.

Support for different sleep positions Side sleepers, back sleepers, and stomach sleepers all need different levels of firmness and pressure relief. If you and your partner have different preferences, a mattress that offers a balanced feel across its surface — neither too firm nor too soft — tends to work well for shared use.

Visit the Somnuz mattress store or explore our collection online to find king size options suited to different sleep styles and room setups.

 

FAQs: King Size Mattress in CM

What is the standard king size mattress size in cm? A standard king size mattress measures approximately 183 cm wide by 190 cm long. Exact dimensions can vary slightly between brands, so always confirm with the specific manufacturer before buying — particularly when matching to an existing bed frame.

What is the difference between a king and super king in cm? Both are 183 cm wide. The difference is in length — a standard king is 190 cm long, while a super king is 200 cm long. The super king suits taller sleepers who find a standard king length slightly short.

What room size do I need for a king size mattress? As a general guide, a room of at least 400 cm wide and 380 cm long allows a king size mattress to fit with comfortable clearance on the sides and at the foot. Room layout, door placement, and furniture all affect this in practice — marking out the dimensions on the floor before buying is the most reliable way to check.

Will a king size mattress fit in an HDB master bedroom? It depends on the flat type and layout. Many HDB master bedrooms can fit a king, but clearance on the sides can be limited in smaller rooms. Measure your room carefully and mark out the footprint before deciding — a queen is sometimes a more comfortable fit proportionally.

Does a king size mattress need a special bed frame? It needs a king size bed frame with matching internal dimensions. Standard queen or single frames will not accommodate a king mattress. Always confirm both mattress and frame dimensions before purchasing, particularly if buying from different sources.

Is a king size mattress worth it for a couple? For many couples, yes. The extra width compared to a queen is noticeable in practice, particularly for those who move around during the night or simply sleep better with more room. Whether it's worth it depends on your bedroom size and how much the additional space will genuinely improve your sleep.

 

Ready to Find Your King?

A king size mattress is a considered investment — and getting the dimensions, the room fit, and the comfort right from the start means you won't be second-guessing it six months later.

Explore our king size mattress options or visit our showroom to see the range in person, try different feels, and get honest guidance from our team — no pressure, just practical help finding what works for you.