Comfort rating (sleeping bag)

Sleeping bag comfort ratings are designed to help users compare different models and select appropriate gear for expected conditions. Under standardized testing protocols, such as those used in parts of Europe and elsewhere, a test mannequin with sensors is placed in a controlled environment inside the bag. From this, several temperature ratings may be derived, including comfort, limit, and extreme values.

The comfort rating is intended to represent a temperature at which an average sleeper, often modeled as a person sleeping in a relaxed posture, could expect to remain reasonably comfortable over a night. The limit rating generally refers to a lower temperature at which a person may remain functional but less comfortable, while the extreme rating represents a survival-focused threshold.

Real-world experiences can differ from laboratory conditions. Factors such as individual metabolism, clothing layers, the insulating value of the sleeping pad, shelter characteristics, wind, humidity, and recent fatigue or caloric intake all influence how warm or cold a person feels.

For long-distance hikers, comfort ratings serve as guidelines for matching sleep systems to likely temperature ranges. Many people select bags or quilts with some margin below forecast lows, while others rely more heavily on clothing layers to extend warmth. Understanding the limitations of rating systems helps set realistic expectations.