If you’re a fan of coil mattresses, you know that it’s hard to replicate that bouncy feeling with a different mattress type. Innerspring mattresses are the oldest type of mattresses that are still commonly used today, and it’s safe to say they’ll never go out of fashion.
Among their many benefits are durability, breathability, and relative portability. If you’ve set your eyes on a coil mattress, you might think you’ve done your research—but there are still a few important things to take into account before you make a purchase.
Did you know that there are several different mattress coil types? Or that factors like coil count and coil gauge make a difference in the feel of your mattress? Here’s everything you need to know about coils in mattresses.
What are mattress coils?
Mattress coils are the metal support coils that form the core of an innerspring mattress. They’re designed to flex in response to pressure and spring back when that pressure is removed. The more pressure is placed on them, the firmer the support they provide.
Most innerspring mattresses today contain additional layers made with other materials, such as memory foam and latex, for added comfort. However, that essential quality of “springiness,” which is the coil mattress’s defining characteristic, is due to the mattress coils.
Most mattress coils are made with tempered steel. Tempering is a process of heat treating. It improves the toughness and durability of the metal, which ensures the coils are able to retain their original shape through years of use.
There are many benefits to sleeping on a coil-based mattress. They sleep cool since the space between coils allows for excellent air circulation. They support a range of sleeping positions and are great for those who tend to shift positions during the night as the inherent “springiness” makes it easy to move across the surface of the mattress. They’re also generally cost-effective and durable: a well-made coil mattress can last you up to 10 years or more.
However, as with any type of mattress, there’s great variability when it comes to coil-based mattresses in terms of support, comfort, durability, and other aspects. These are determined by the type of coils, coil count, and coil gauge.
Mattress coil types
There are four major mattress coil types.
Also called “open” coils, these are the oldest and most basic type of mattress coils. Bonnell coils are shaped like an hourglass, where the thinner portion in the middle flexes in response to minimal pressure, and the thicker parts at the top and the bottom are designed to support greater pressure. Bonnell coils are often wired together to form a continuous unit. This means they aren’t very good at controlling motion transfer and also that the friction from the coils might make these mattresses somewhat noisy.
Mattresses made with Bonnell coils aren’t the best at supporting the weight of a fully grown adult on a daily basis, and they aren’t as durable as other innerspring mattresses. For these reasons, they’re probably best suited for kids who will eventually outgrow their childhood bed or guest bedrooms where the usage of the mattress will be limited to a few times a year in most cases.
Offset coils are similar to Bonnell coils in that they’re also hourglass-shaped and interconnected. The difference is the top and bottom of the offset coils are squared rather than rounded. These coils flex like a hinge when compressed and provide stronger pushback under greater pressure. That hinging effect makes them quieter and more responsive, better at controlling motion transfer, and more suitable for supporting an adult’s weight.
Continuous wire coils
Continuous wire coils are the most similar to offset coils, but they have several rows of singular wires molded into the shapes of a circle. This structure gives the mattress a more stable core and makes it more durable. However, they might be noisier and not as great at controlling motion transfer as offset coils. This might be problematic if you consistently share your bed with a partner.
They also don’t offer the same level of contouring and work best in mattresses that have thick comfort layers or when paired with a foam mattress topper for additional comfort.
Pocketed coils are multiple smaller coils individually encased in fabric. Since each coil functions independently and flexes only when pressure is placed directly on it, pocket coils are much better at contouring to the sleeper’s body than other types of coils. Because the coils aren’t physically attached to each other, they excel at controlling motion transfer. They’re also quieter than other innerspring mattress types.
Because of the complex construction, mattresses made with pocketed coils are more expensive than other types of coil mattresses—but they’re also more durable and supportive.
Mattress coil count
Coil count is the total number of coils in a mattress and is another factor to consider when choosing a coil mattress. It’s less important than coil type but worth being aware of.
The coil count of an innerspring mattress typically ranges from 400 to 1,200, depending on the mattress size. Since Bonnell and offset coils are larger, mattresses made from these types of coils usually have a lower coil count, while mattresses made with pocketed coils will generally have a higher coil count.
A good rule of thumb is that the minimum coil count for a full-size mattress should be 300 coils, for queen-sized at least 400 coils, and for king mattresses at least 480 coils.
Keep in mind that a higher coil count won’t necessarily translate into better comfort or support as it doesn’t say anything about the quality of the coils or the mattress.
Saatva mattress coil count
Here’s a look at the coil count in the Saatva Classic innerspring mattress:
|Saatva Classic Mattress Size||Pocketed Coils||Support Coils (Base)||Total Coils|
|Cal king & split king||1,088||520||1,608|
Mattress coil gauge
Coil gauge refers to the thickness of a coil. Coil gauge usually ranges between 12 and 17, with 12 being the thickest coil and 17 the thinnest. A lower gauge means a thicker, more supportive coil, while a higher gauge means a thinner, more flexible coil.
A higher gauge is a better option if you want a softer mattress, but a lower gauge usually lasts longer. Thicker springs are also a better choice if you’re on the heavier side since they provide stronger support. A coil gauge in the range of 13 to 15 should ensure the ideal balance of comfort, support, and durability.
Saatva mattress coil gauge
The Saatva Classic has two layers of coils: a base coil unit with 13-gauge coils for maximum durability and a responsive layer of individually-wrapped 14.5-gauge coils for maximum comfort.
Check out Saatva's selection of high-quality innerspring mattresses
Saatva Classic Innerspring Mattress
Our flagship luxury mattress is expertly engineered with coil-on-coil construction for durability, a layer of memory foam for enhanced back support, and a cushiony Euro pillow top for extra comfort.
Saatva HD Mattress
This luxury hybrid innerspring mattress is specifically engineered to support people weighing between 300 and 500 pounds. Plush upper layers made of foam and latex deliver comfort, while a high-durability coil base offers support.
Latex Hybrid Mattress
This hybrid mattress combines the pressure-free support of natural latex with the classic innerspring feel. Handcrafted with pure materials for the ultimate in cool and healthy sleep.
Memory Foam Hybrid Mattress
This memory foam hybrid mattress features the perfect balance of body-contouring and responsive feel. Enjoy the innovative cooling system, which prevents overheating.
What are coils in a mattress?
Coils are metal rings that form the core of an innerspring mattress. They support the sleeper’s body by flexing under pressure and springing back when that pressure is released.
Are coil mattresses good?
Coil mattresses offer many benefits including durability, airflow, and pressure relief. The quality of a coil mattress depends on the type of coils and to a lesser extent coil gauge and coil count. Different mattress coil types create different mattresses to suit any sleeping position, body type, and budget.
Is it better to have more or fewer coils in a mattress?
A higher coil count in an innerspring mattress doesn’t necessarily translate to a higher-quality mattress. That’s because the number of coils doesn’t tell you anything about their type or the quality of the metal they’re made with.
What is the best coil number in a mattress?
A good rule of thumb is that the minimum coil count for a full-size mattress should be 300 coils, for a queen-sized at least 400 coils, and for a king mattress at least 480 coils.
What is a good coil gauge for a mattress?
A lower gauge means a thicker, more supportive coil (and a firmer and more durable mattress), while a higher gauge means a thinner, more flexible coil and a softer mattress. The choice depends largely on your personal preference and body type (heavier bodies tend to need more supportive mattresses). If you’re unsure, a coil gauge in the range of 13 to 15 should ensure the ideal balance of comfort, support, and durability.
Choose the best innerspring mattress at Saatva
Saatva offers a range of innerspring mattresses to suit your sleep preferences. All of our innerspring mattresses are made with high-quality, durable tempered steel coils to provide you with excellent comfort and support while you sleep.
Plus, our mattresses come with a 365-night home trial and lifetime warranty so you can try one out before deciding if it’s right for you. Take our mattress quiz to find out which one of our mattresses is right for you.