Will Your Sleep System Keep You Warm?
Calculate your ultralight sleep system's temperature rating in seconds. Factor in your quilt, sleeping pad, clothing, and personal warmth to find your true comfort zone.
Your Equipment
Enter the manufacturer's temperature rating (Comfort or Limit)
Your sleeping pad's R-value (typically 2-7 for most pads)
The coldest temperature you expect to encounter (for gear recommendations)
Personal Factors
Base layers only
Normal temperature sensation during sleep
More Tools
Frequently Asked Questions
How accurate is the sleep system calculator?
Our calculator provides estimates based on widely accepted principles from the ultralight backpacking community. Actual comfort varies based on humidity, wind, shelter, metabolism, and fatigue. We recommend adding a 5-10°F safety margin for critical trips.
What R-value sleeping pad do I need?
For 3-season backpacking (above 20°F), an R-value of 3-4 is typically sufficient. For winter camping (below 20°F), aim for R-value 5+. Our calculator factors in your pad's R-value to give you an adjusted comfort temperature.
Can I layer two quilts together?
Yes! Layering quilts is a popular strategy for extending your temperature range. Use our Quilt Layering Calculator to estimate the combined temperature rating. The general formula is: Combined Rating = Inner Quilt Rating - ((70 - Outer Quilt Rating) / 2).
What's the difference between Comfort, Limit, and Survival ratings?
EN/ISO Comfort rating is the temperature at which an average woman can sleep comfortably. Limit rating is for an average man in a curled position. Survival rating is the extreme limit. We recommend using Comfort ratings for trip planning.
Understanding Sleep System Temperature Ratings
Your sleep system's actual performance depends on much more than just your quilt or sleeping bag's temperature rating. Four key factors determine how warm you'll sleep:
1. Quilt/Sleeping Bag Temperature Rating
Manufacturers rate their products using different standards (EN/ISO Comfort, Limit, or Survival ratings). EN/ISO Comfort ratings are the most reliable for planning purposes. Many cottage brands use limit ratings, which represent the lower temperature at which an average person can sleep in a curled position.
2. Sleeping Pad R-Value
Your sleeping pad's R-value is often more important than people realize. Heat loss to the ground can be significant, and no amount of quilt loft can compensate for inadequate ground insulation. A sleeping pad with an R-value of 4+ is recommended for temperatures below freezing. Check our complete R-value guide to learn what R-value you need for different conditions.
3. Clothing Layers
What you wear to bed can add 5-15°F to your effective temperature rating. Base layers, fleece, and even down jackets can extend your quilt's usable range significantly. For even more warmth, consider layering two quilts together — our quilt layering calculator can help you estimate the combined temperature rating.
4. Personal Sleep Temperature
Individual variation in sleep temperature is significant. "Cold sleepers" may need to add 10-15°F to manufacturer ratings, while "hot sleepers" can often push ratings 10°F colder than advertised. Knowing your personal tendencies helps you make better gear decisions. Browse our ultralight gear database to compare quilts and sleeping pads from top cottage and mainstream brands.
Why Use Our Calculator?
Our sleep system calculator combines all four factors into a single, easy-to-understand estimate. Instead of guessing whether your 20°F quilt will work for a 25°F night, you can input all your variables and get a personalized comfort temperature range.
Disclaimer: This calculator provides estimates based on general principles. Actual comfort varies based on many factors including humidity, wind, shelter, metabolism, and fatigue. Always err on the side of caution and bring backup warmth options for critical trips.