Coil gauge is the thickness of the steel wire used in a mattress’s coils. It runs on a scale where a lower number means a thicker, firmer, more durable wire, and a higher number means a thinner wire that flexes more easily for a softer, more contouring feel. Around 12 to 13 gauge is firm and sturdy, while 15 to 16 gauge is softer and more responsive.
How the gauge scale works
Gauge is a bit counterintuitive: the numbers run backward. A 12-gauge coil is thicker than a 15-gauge coil. Thicker, lower-gauge wire resists compression, so it feels firmer and tends to last longer under weight. Thinner, higher-gauge wire gives more easily, so it feels softer and contours more closely.
| Gauge | Wire | Feel |
|---|---|---|
| 12 to 13 | Thick | Firm, very supportive, durable |
| 14 | Medium | Balanced support and give |
| 15 to 16 | Thin | Softer, more contouring and responsive |
What gauge means for you
Heavier sleepers and anyone who wants firm, long-lasting support often do better with a lower-gauge coil. Lighter sleepers and side sleepers who want the coils to give and cushion may prefer a higher gauge. Many quality beds use different gauges in different zones, firmer under the hips and softer at the shoulders. That idea is covered in zoned support.
Gauge is only one part of a coil system. Coil type and count matter too, which we cover in pocket vs Bonnell coils and does coil count matter. Put it together with our mattress types guide.
Frequently asked questions
Is a lower or higher gauge coil better?
Neither is universally better. Lower gauge is firmer and more durable; higher gauge is softer and more contouring. The right choice depends on your weight and the feel you want.
What gauge is best for a heavy person?
Heavier sleepers usually benefit from a lower gauge, thicker wire around 12 to 13, for firmer support and durability.
Do all coils in a mattress use the same gauge?
Not always. Zoned mattresses often use firmer, lower-gauge coils under the midsection and softer, higher-gauge coils at the shoulders and legs.
