Body Weight and Mattresses: The Number One Thing That Matters

Why spring tension matters the most

Your weight changes everything about how a mattress feels. The same mattress feels completely different to a 60 kg person versus a 100 kg person. This isn't about preference. It's physics. Body types vary, and so do the needs of different body types.

• When you're too light for the springs: The springs won't yield to your body. Instead, your body yields to the springs. You'll feel pressure points on your shoulders and hips. You'll wake up stiff and sore because your body spent the night contorted, trying to match the unyielding sleep surface underneath. This often happens to lightweight sleepers on firm mattresses.

• When you're too heavy for the springs: You sink too far into the mattress. Your hips drop down, your spine curves unnaturally, and you get that "sleeping in a hole" sensation. This is the textbook definition of "lack of support" - your body falls out of proper spinal alignment. This is a common issue for heavier sleepers on a soft mattress or medium soft option, not designed to support larger bodies.

• When the spring tension matches your weight: Your body maintains its natural curve. Weight distribution is even across the sleep surface. Your shoulders and hips sink just enough. Your middle torso gets proper support. You wake up in the same sleeping position you fell asleep in because you weren't tossing around looking for comfort. This provides the best support and pressure relief.

What is "enough support?": the car suspension analogy

Think of a car suspension. You wouldn't put heavy truck suspensions into a hatchback. The ride would be terrible. That's exactly what happens with mattresses. If you're heavier, you need stiffer springs. If you're lighter, you need softer springs or a lower firmness level. Sometimes there's nothing wrong with your mattress quality. You just got the wrong spring tension for your body weight. This is key to finding the best mattress firmness. Firmer springs are needed to support larger bodies so they don't sink too much. Smaller frame bodies need softer springs so they don't feel pressure points. A mattress is a suspension system for your body; a "ride." Great support = great ride.

Julie's Story: 30 years of sleeping on the wrong mattress springs

Here's a true customer story. Julie is a lightweight person. For 30 years, she went to mattress stores where salespeople weren't aware that different body weights require different spring tensions. They weren't installing bad springs - they were installing the WRONG springs for her lighter frame. She researched online and bought "the best mattress in Australia" from a top-ten list. It was extremely uncomfortable. Then she found a mattress manufacturer (Karl) who said, "You're lightweight, and you've got springs designed for a much heavier person. Let's sort that out".

We swapped to springs matched to her body weight. Suddenly, she felt like she was floating. All of Julie's previous mattresses may have been high quality. But quality doesn't matter if the springs are too firm for your weight.

"I am fairly light in weight and for the past 30 years or so as I have aged, I have never found a bed that was comfortable, or that didn't hurt my shoulders, hips or back... Most importantly, my bed doesn't cause me any pain". - Julie D., Melbourne

How body weight matching works: spring tension vs weight categories guide

The Ausbeds spring tension guide works for about 80% of our customers. Based on 15 years and thousands of spring swaps, here's what I've learned:

The difference between these levels? As little as 0.1mm in steel wire thickness. That tenth of a millimetre creates a completely different mattress feel.

What about the other 20%?

Not everyone fits the chart perfectly. The same weight doesn't mean the same preference. We've seen two 95 kg customers end up comfortable on opposite ends of the spectrum - one on Cloud 3, another on Cloud 9. This highlights that your preferred sleeping position or sleep style can affect the ideal firmness level.

This is why we build in three mattress firmness levels of adjustment for every mattress:

• Order Level 6 (Medium firm) -> Adjust to 5, 6, or 7 at home (flip springs, add/remove felt layer)

• Order Level 9 (Firm mattresses) - > Adjust to 8, 9, or 10 at home

• Need bigger change? We'll swap the spring unit (free in the first 3 months)

You're not locked into your initial choice. You test it, adjust it, and find your perfect mattress configuration.

Why most companies don't do this

The problem is logistics. With 3 spring tensions across 5 mattress sizes, you go from 5 product variations to 1559. That's operational complexity most companies won't deal with. They'd rather make one "universal" mattress and hope it works for everyone61. The mattress industry average refund rate hovers around 10-20%.

Why do we know this works

The results speak for themselves. After implementing systematic body weight matching:

• Refund rate dropped, below standard industry levels

• 80% success rate with initial weight-based recommendation

• 20% require individual customisation beyond weight predictions

What this system fixes (that nothing else can)

Heat retention

When spring tension is correct, your body sits at the right height in the mattress. You don't need excessive foam to compensate for a wrong spring. Less foam, less heat trapped. Too many mattresses use very firm springs (manufacturers think this prevents sagging), then pile on thick foam layers to make them comfortable. That creates an oven.

Premature sagging

When springs are too firm for your weight, the foam gets crushed between your body and the unyielding spring tops. This speeds up foam deterioration dramatically. When spring tension matches your body weight, the spring absorbs its share of the load. The foam lasts years longer because it's not taking all the punishment.

Pressure points and pain

The ultimate goal: distribute pressure away from the hips and shoulders, move it into the middle torso. This allows your body to maintain its natural curve. Correct spring tension to body weight achieves this goal. Wrong spring tension makes it impossible, regardless of what foam you put on top. The springs decide your body shape. The foam just changes how it feels.

What if my sleeping partner weighs much more/less than me?

The 36kg weight differential

One couple came to us with a problem: 36 kg weight difference between partners. He thought he needed a very firm mattress (Aurora 9). She was considerably lighter. They finally landed on a 6 (medium firm mattress), where we flipped her side of the springs to the softer side for her weight. The surprising part? Despite being "much softer than the original 9," it doesn't sag under his weight. The springs are just calibrated for a different load range.

Split tension solution

For couples with very different body weights, we can build half-firm, half-medium configurations. Your side gets springs matched to your body weight. Their side gets springs matched to their body weight. You each get the support your specific body weight requires. This is a great solution for couples where one sleeping partner is a side sleeper, and the other is a back sleeper. Check our half-half mattress to learn more about this.

What about spring count, materials, and other specs?

Do they matter?

Yes. But only if you get spring tension right first. Our innerspring mattresses' construction includes 986 honeycomb pocket springs (Queen) vs industry's typical. Having 986 perfectly-engineered springs doesn't help if they're the wrong tension for your body weight.

What about the foam?

If you have the right mattress firmness from the springs, you can choose foam based purely on preference:

• Polyfoam (Cooper range): Most affordable, works great when springs are correct

• Memory foam: Adds motion isolation, sleeps warmer

• Natural latex (Aurora & Cloud): Most durable, better pressure relief, cooler

The springs hold your body in proper spinal alignment. The foam determines how it feels getting there.

Sleeping position: Does being a back/ stomach sleeper or side sleeper make a difference?

Yes, but again, only secondary to body weight.

Stomach sleepers

When you sleep on your stomach, there are no shoulders or hips that need to be absorbed into the mattress. Also, when you are on your front, if your stomach drops into the mattress, it can overarch your back, causing some pain in the small of your back. Stomach sleepers in my shop get firmer springs. Otherwise, the back arches in.

Side sleepers

You are in the category of someone who would greatly benefit from trying as many mattresses as possible. On your side, you will feel a lot of pressure on the hips and shoulders if you get a slab [that's too firm].

Heavy side sleepers (110kg+ example):

One customer asked, "I'm quite heavy (110kg) and around 185cm. I am a side sleeper and sometimes sleep on my stomach. " For heavier people, I increase the spring tension from medium to extra firm, but I also make sure the top is well-padded. Heavier sleepers will have a more challenging time with comfort because there is more weight to be distributed.

The only way I have been able to reduce the pressure for someone at a higher bodyweight is to make sure the spring tension is high enough, by increasing the wire thickness, and then adding extra cushioning on top. I use more microsprings and latex. One of the problems is right here. I increase the spring tension, so the spine is aligned. The customer may now be aligned, or not sinking in, and then they may say, "Now I feel too much pressure". What's happening is the springs are doing their job, but the pressure is now concentrated on the hips and shoulders. And it feels too firm. The only way I see around this is to add more microsprings and latex (cushioning). This distributes pressure away from the pressure points.

Combination sleepers:

Standard recommendations work for approximately 80% of customers with typical body composition, mixed or side sleeping positions, no significant health conditions affecting sleep, and average firmness preferences. People who have found the perfect mattress spring tension

Real customers who have found the perfect mattress spring tension

After 50+ years of premium mattresses

"Getting the right spring rate for body weight is essential, but no other mattress manufacturer seems to realise this... The result is the first truly satisfactory mattress we have experienced in 50+ years... We have bought many premium mattresses over the years, and this is the first one ever that hasn't been a disappointment". - Tony M.

Very different weights, both with back pain

"My partner and I are very different weights, and have been looking for a bed that would suit both of our needs, especially since we both also suffer from back pain... We ended up choosing the Cloud range, in a firm mattress and medium firm half/half... Our back pain has reduced noticeably, the different mattress types are not a gimmick, and you can feel the differences in each of our sides". - Nick Jones, Sydney

Ready to find your ideal spring tension?

So, to wrap up, here's what you need to do to achieve better sleep:

1. Use your body weight to find your starting level (3, 6, 9, or 12)

2. We build your mattress with those springs

3. Test it for 1-2 weeks (your body needs adaptation time)

4. Make DIY adjustments if needed (flip springs, move felt)

5. If you need a bigger change, we swap the spring unit (free in the first 3 months)

What you get:

• 120-night trial period

• 2 free component swaps in the first 3 months

• 10-year warranty

The mattress industry makes this complicated because complexity sells. We make it simple because physics works. Your body weight determines the spring tension you need. We've spent 15 years proving this works. Now it's your turn to test it.