An open coil mattress has a linked unit of metal springs that move together under pressure. It can be a lower-cost choice if you like a bouncy bed. Its spring unit tends to be breathable. The linked springs can pass movement across the bed, so you may feel a partner move.
An open coil mattress uses springs linked into a grid, rather than springs in separate pockets. The metal springs support the mattress and flex under pressure, becoming firmer as more pressure is applied.
In a Bonnell unit, for example, pressing down on one coil can pull its neighbors down too. Read more about the wider category in What is a spring mattress?.
Bonnell, offset and continuous are types of connected coil units. Some use open coil and Bonnell to mean the same thing. Others include more types under open coil.
Bonnell: Hourglass-shaped coils have knotted ends and are joined by thin spiral wires. The narrow middle gives under initial pressure, while the wider ends resist deeper compression.
Offset: These coils are related to Bonnell coils. They share the hourglass shape and connecting wires. But their sides are squared, not fully rounded at the top and bottom.
Continuous: A single wire is formed into rows of loose coils, with the rows connected by spiral wires.
An open coil mattress can be a good choice if you want a lower-cost, bouncy bed. Coil spring mattresses, including open coil, tend to be breathable and can feel cool.
The tradeoff is that linked springs can disturb a bed partner, and these coils tend to wear out faster than pocket springs. Bonnell coils are among the less expensive coil types, but they can be prone to sagging in the center.
An open coil mattress does not have one set firmness. Check the comfort layer and core: the comfort layer mainly affects firmness, while the core mainly provides support.
Your weight, body type and sleep position affect what feels comfortable and supportive. For side sleeping, medium-soft to medium firmness can cushion the shoulders and hips while supporting the spine. People under 130 pounds usually need a softer mattress, while people over 230 pounds may need firmer support.
In a test of one 8-inch open-coil hybrid, a lightweight sleeper felt supported on their stomach. They did not feel supported on their back or side. Heavier testers felt they sank into the coils and lacked support.
Couples can use an open coil mattress, but you may feel your partner move. Open-coil Bonnell springs share wire paths. You will typically feel more of a partner's movement on them than on pocket springs.
Check the upper layers as well as the springs. A thick comfort layer can absorb some movement, but it won't guarantee a still surface.
Open coil mattresses can be very bouncy. Coils expand and contract under pressure, giving coil-based beds bounce. These beds are generally easier to move on than all-foam beds.
Innerspring coil systems can creak as they age. Foam, latex or fiber comfort layers can help muffle that sound.
You can consider an open coil mattress for a guest room or child's bed. For a main bed, check the model's support and intended use.
For example, Texas Mattress Makers recommends its TMM Value Mattress only for children, teens or spaces used less often. For an upper bunk, check that the guardrail tops are at least 5 inches above the mattress.
Choose pocket springs for more independent movement from the coils. Consider basic open coil if a lower price is the priority.
Pocket springs sit in individual fabric pockets, while Bonnell open coils are joined in a wire grid. Connected Bonnell coils respond less precisely to different body areas. Pocket coils can respond differently beneath the shoulders and hips. A partner's movement is also typically felt more on an open-coil Bonnell unit.
Consider memory foam for a closer hug. A hybrid offers cushioning over a coil core. Memory foam beds use foam rather than metal springs for support. A hybrid pairs a coil core with a comfort system that can include foam or latex.
Memory foam tends to mold more closely to your body and give more pressure relief than an innerspring. Innersprings tend to feel more even and bouncy. Hybrids can mold to your body and have some bounce. They also tend to have firmer edge support than all-foam beds. Innersprings are generally bouncier than hybrids or all-foam beds. They offer less pressure relief and let more movement pass through the bed.
Open coil can be a lower-cost option, but the price depends on the mattress. A basic open-coil spring mattress can start at less than £100; brand, size and materials can all affect the cost.
Bonnell coils cost less to make and assemble than other coil types. They are usually found in lower-priced entry-level innerspring mattresses. Pocket-sprung mattresses tend to cost more than basic open-coil models.
Check the whole mattress, not just its spring label. Your weight, body type and sleep position affect the comfort and support you need.
Look at the upper layers. A transition layer sits beneath the comfort layers and acts as a buffer above the core; it can limit excess sinkage. An open coil hybrid can pair linked springs with a memory foam comfort layer.
Compare coil details in context. Lower-gauge coils are thicker and firmer. A higher coil count alone does not show that a mattress is sturdier or longer-lasting.
Check the base requirements. Follow the mattress maker's instructions for a supportive base, since inadequate support can lead to sagging.
Innerspring mattresses can sag as springs and thin comfort layers wear. In traditional innersprings, coils can lose their original height over time. This can lead to sagging and weaker support. Bonnell coils can be prone to sagging in the center.
Traditional innerspring mattresses last about six years on average. That is not a guaranteed lifespan for every open coil model. Heavier sleepers may see sagging sooner, and a mattress used by a couple may wear out sooner than one used by a single person.
Rotate about every three months, unless the maker advises otherwise. Use a mattress protector to help the mattress last longer. For more on general lifespan, see How long do innerspring mattresses last?.
They can: innerspring mattresses typically sleep cooler than memory foam mattresses because air can flow through the spaces between coils. Check the top layers, too, since a thick foam layer may reduce that cooling effect.
Follow your mattress maker's base requirements; inadequate support can lead to sagging. If you want an adjustable base, check that it works with your mattress. Leggett & Platt says its adjustable bases do not work with innerspring mattresses that have a border wire.
We read 23 published pages from 13 sites (Sleep Foundation, bedguide.co.uk, which.co.uk, mattressnut.com and 9 more), checked in October 2026. Every sentence in the answers above cites one of them; the offer card at the end names its own source. This page reports published sources only; we did not test mattresses in person.