Mattress coils are metal springs that form the support system of innerspring and hybrid mattresses. These mattress types are typically designed with softer layers that sit atop a firmer support core made of metal coils. Mattress coils are engineered to evenly distribute your body weight and provide the necessary support to maintain spinal alignment during sleep.
Available in a variety of designs, coils have been used in mattresses for over 150 years and remain popular today. Many people choose coil-based mattresses for their reliable support, responsiveness, and breathability. When shopping for a coil-based mattress, it’s important to consider the type, number, and thickness of coils. Whether you have your eye on traditional Bonnell coils or modern pocketed designs, we’ve created this guide to help you find the mattress that’s best for you.
What Do Mattress Coils Do?
Mattress coils absorb pressure and provide pushback to support a sleeper’s body. Coils also significantly affect the feel of a mattress. A good coil-based mattress feels supportive, keeps the spine aligned, and has just enough bounce for easy movement. Additionally, the space in and around coils allows air to flow through, keeping the mattress cool.
The specific benefits of mattress coils depend on the type, gauge, and number of coils. Sleepers who benefit most from coil-based mattresses include those who appreciate firm support, enjoy a cooler sleep surface, and prefer a responsive feel over the deep hug of foam mattresses.
Which Mattress Types Have Coils?
Coils are found in innerspring and hybrid mattresses. Innerspring mattresses rely almost entirely on coils to provide support, usually having a thin comfort layer and a firmer feel. Hybrid mattresses blend coils with layers of foam or latex, achieving a balanced feel that melds the support and responsiveness of coils with the comforting properties of other materials.
Compared to other mattress types, coil-based mattresses generally offer better edge support, airflow, and responsiveness at a lower price.
Types of Mattress Coils
The most common types of mattress coils include Bonnell, pocketed, continuous, and offset coils. Each coil type has a unique design that influences a mattress’s feel, performance, and cost.
Bonnell Coils
Bonnell coils are the oldest coil type used in mattresses and are still widely available today. Recognizable by their hourglass shape, these coils are interconnected, which helps to support the body by distributing weight across the layer of coils.
Bonnell coils are typically less expensive to produce than other designs, making mattresses with these coils a more budget-friendly option. However, their interconnected design does allow for some motion transfer, and they are prone to making noise. Bonnell coils also lack the targeted support found in more contemporary coil designs.
Pocketed Coils
Pocketed coils, also known as Marshall coils, are a common coil type in which each coil is individually wrapped in fabric. The fabric between coils is sewn or glued together, allowing coils to move independently of each other without sacrificing the mattress’ structure.
Because they aren’t interconnected, pocketed coils excel at conforming to the body’s curves, offering excellent support and pressure relief. They also minimize motion transfer, making them ideal for couples and people who share the bed with kids or pets. While mattresses with pocketed coils tend to be pricier than those with Bonnell coils, they are available in a range of price points.
Continuous Coils
Continuous coils are constructed from a single piece of wire formed into a series of interconnected springs. This interlocking design creates a durable and stable support core that typically has a firm feel. To offset this, mattresses with continuous coil systems often have multi-layered comfort systems.
Although cost-effective, continuous coil systems may produce noise and transfer motion more readily compared to other types of coils. Despite these drawbacks, they remain a popular choice for those seeking a firm and durable mattress without a significant investment.
Offset Coils
Offset coils are like Bonnell coils, with an hourglass shape. Unlike Bonnel coils, the tops and bottoms of offset coils have squared-off edges. This simple change in shape allows the coils to hinge together and conform more closely to the body. The offset coil design also reduces motion transfer more effectively than Bonnell coils and provides more targeted support.
Offset coils are more expensive to manufacture than Bonnell coils, but offer a better balance of performance and cost, making them popular in mid-range to high-end mattresses.
Microcoils
Also known as nanocoils or minicoils, microcoils are small, flexible coils used in the comfort or transitional layers of a mattress rather than the support core. These coil layers are typically only 1 to 2 inches tall, and are used in luxury hybrid mattresses to enhance responsiveness and breathability while providing additional support and pressure relief.
Microcoils can also be stacked on other coil layers, called a coil-on-coil design, or alternate with layers of foam. The inclusion of microcoils can add to the cost of a mattress but significantly improves its performance.
Different Mattress Coil Types
| Pros | Cons | |
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| Bonnell |
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| Pocketed |
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| Continuous |
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| Offset |
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Coil Gauge
Coil gauge refers to the thickness of the wire used in mattress coils — the lower the number, the thicker the wire. Coil gauges used in mattresses typically range from 13 to 17. A lower gauge resists pressure and results in a firmer mattress feel, while a higher gauge allows for easier compression and a softer feel. Coil-on-coil designs often layer different gauges of coils on top of one another to create a distinct feel.
For sleepers looking for a durable mattress with a firmer feel, we recommend mattresses that incorporate a lower gauge coil. This is especially true for heavier individuals and those who sleep on their stomach or back. Higher gauge coils result in a softer feel, making these mattresses better suited for side sleepers and those wanting a plusher feel that contours more closely to the body.
The type of coils used in a mattress also affect the optimal coil gauge:
- Bonnell: Bonnell coils can be found in low, medium, or high gauge. Because this design is highly responsive, lower gauge coils can help to add some resistance and prevent early sagging.
- Pocketed: Pocketed coils often have high gauge coils. Thinner wire allows each coil to flex independently and better adapt to the body’s contours. High gauge pocketed coils are great for deep pressure relief and reducing motion transfer between sleep partners.
- Continuous: Continuous coils are generally found in a medium to high gauge that give enough flexibility for contouring while maintaining sufficient support to prevent early sagging.
- Offset: Offset coils are found in a medium to high gauge. This range allows the coils to conform to the body’s shape without sacrificing support.
Coil Count
Unlike coil gauge, which describes the thickness of the coils, coil count refers to the number of individual coils within a mattress. A higher coil count sometimes indicates higher quality, as more coils can facilitate better support and help a mattress contour more closely to the body.
The typical coil count for a queen size mattress is between 400 and 1,200 coils, depending on the mattress’ design and the specific type of coil used in its construction. That said, a higher coil count doesn’t always mean a better mattress. It’s also important to consider the type and gauge of the coils.
What Is the Best Coil Count for a Mattress?
Our favorite queen mattresses have around 800 to 1,200 coils. However, the ideal number of coils really depends on the type and height of coils used, the gauge, and the quality of the metal. These factors significantly influence the feel, performance, and durability of a coil-based mattress.
About The Author
Staff Writer, Product Testing Team
Garen is a health and lifestyle content creator. She realized the importance of sleep when her children made getting a good night’s rest more challenging. Garen is always learning something new about the wide world of sleep and sleep products. Married with two girls, ages 7 and 11, she is a book nerd and a lover of pop music, travel, and the Pacific Northwest.
- POSITION: Side Sleeper
- TEMPERATURE: Neutral Sleeper
- CHRONOTYPE: Wolf
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