What Are Mattress Springs Made Of? Understanding Coil Materials and Construction

If you’re asking “What Are Mattress Springs Made Of”, you’re likely trying to understand what’s inside a traditional innerspring or hybrid mattress and how those materials affect comfort, support, and durability. This FAQ-style guide walks through the most common materials, how they’re used, and what that means for you as a sleeper.

What Are Mattress Springs Made Of in Most Modern Mattresses?

In almost all modern innerspring and hybrid beds, mattress springs are made primarily from metal coils, most often:

High-carbon steel wire
Steel alloys (steel mixed with other metals for specific properties)

The steel wire is drawn (stretched and thinned), hardened, and then formed into coils. These coils are then arranged into a support system under the comfort layers of the mattress.

Some key points:

High-carbon steel is popular because it can be tempered (heat-treated) to become strong, springy, and resilient.
Steel gauge (thickness) affects how firm or flexible the spring feels. Lower gauge numbers mean thicker, usually firmer coils; higher gauge numbers mean thinner, more flexible coils.
Coils may be connected together or individually wrapped in fabric, depending on the mattress type.

Why Does the Spring Material Matter?

Knowing what mattress springs are made of can help you understand:

Support and responsiveness – Steel coils tend to respond quickly to movement.
Longevity – Properly treated steel can maintain its shape and resistance for many years of regular use.
Weight distribution – A well-designed coil system can help distribute body weight across the bed.

While the steel itself is fairly standard, the way it’s processed and arranged makes a noticeable difference in how a mattress feels.

What Types of Steel Springs Are Used?

Bonnell, Offset, and Continuous Coils

These are traditional interconnected spring systems, usually made from tempered steel wire:

Bonnell coils – Hourglass-shaped coils linked together with helical wires.
Offset coils – Similar shape but with flattened edges that hinge as you move.
Continuous coils – Made from a single piece of wire formed into many coils in a row.

In all of these, the springs are still steel, but the design of the system affects motion transfer, firmness, and overall feel.

Pocketed (Encased) Coils

Pocketed coils are individual steel springs wrapped in fabric pockets:

The core spring is still typically high-carbon steel.
Each coil is independently wrapped, allowing them to compress separately.

The fabric encasement is usually made from woven or non-woven textile, which helps reduce noise and limits direct metal-to-metal contact.

Are Mattress Springs Ever Made of Something Besides Steel?

For standard consumer mattresses, steel is overwhelmingly the main material for springs. However, you may occasionally see:

Metal alloys – Coils that are still mostly steel but combined with small amounts of other metals for specific performance characteristics.
Non-steel support components – The springs are steel, but parts of the system around them (edge supports, frames, clips) may include other metals or durable plastics.

Fully non-metal “spring” systems are uncommon in traditional mattresses. Mattresses without steel coils usually rely on foam, latex, or other materials instead of springs altogether.

What Other Materials Surround the Springs?

While the answer to “What Are Mattress Springs Made Of” focuses on steel, the overall feel of the bed also depends on the layers around the coils, such as:

Insulator pads – Often made from felt or fiber, placed between coils and comfort layers to prevent the springs from pushing through.
Foam or latex comfort layers – Placed above the coils for cushioning.
Upholstery fibers – Used for quilting and surface feel.
Edge supports – Extra foam rails or thicker coils around the perimeter.

These materials don’t change what the springs are made of, but they influence how you experience the spring system.

Do Spring Materials Affect Noise or Sagging?

Noise

The steel itself can flex quietly.
Noise usually comes from metal components rubbing together or from old, worn connections.
Pocketed coils, with each spring wrapped in fabric, are often quieter than traditional interconnected systems.

Sagging and Shape Retention

Tempered, high-carbon steel is chosen because it tends to retain its shape under regular use.
Perceived sagging is often due to comfort layers compressing over time, not just the springs themselves.
Coil gauge, total coil count, and overall design all work together with the steel quality to influence long-term performance.

Is There a Difference Between Innerspring and Hybrid Springs?

Both innerspring and hybrid mattresses usually rely on steel coils. The main difference is:

Innerspring mattresses – Mostly coils plus a thinner comfort layer.
Hybrid mattresses – Coils combined with thicker foam or latex layers on top.

In both cases, when you ask “What Are Mattress Springs Made Of”, the answer is still primarily steel, but hybrid designs place more emphasis on the comfort materials above the coil system.

✅ Quick Mattress Takeaways

Key points consumers should understand about “What Are Mattress Springs Made Of”

Main material: Most mattress springs are made from high-carbon steel wire, often tempered for strength and resilience.
Coil types: Bonnell, offset, continuous, and pocketed coils all use steel, but differ in how they’re shaped and connected.
Pocketed coils: These have steel springs inside individual fabric pockets, helping with motion control and noise reduction.
Supporting materials: Insulator pads, foams, fibers, and edge supports surround the springs but don’t replace the steel.
Performance factors: How a mattress feels depends on coil gauge, coil design, and the comfort layers, not just the spring material.
Alternatives: Mattresses without springs typically use foam or latex cores instead of different spring materials.

Understanding what mattress springs are made of gives you a clearer picture of what’s inside your bed and why it feels the way it does. While coil systems vary in design, the core material is almost always steel, working together with the surrounding layers to create your overall sleep experience.