Sleeping Bag & Pad Temperature Guide
Enter the coldest overnight low you expect and how you sleep. You'll get the bag rating to shop for and the pad R-value that keeps the ground from stealing your heat.
Comfort vs limit ratings
Most bags are tested to the ISO 23537 standard (which replaced EN 13537) and carry two key numbers. The comfort rating is the temperature at which a typical cold sleeper stays comfortable in a relaxed position. The limit (or lower-limit) rating is the lowest temperature at which a typical warm sleeper stays comfortable curled up — and it's often the number in the product name. The gap is usually around 10°F.
That's why this tool shops by the comfort rating and adds a margin if you sleep cold, camp somewhere windy or damp.
Why the pad matters as much as the bag
Your bag's insulation is crushed flat under your body, so the ground pulls heat out of you through the pad. The pad's R-value measures that resistance (ASTM F3340 standard). R-values are additive — stack a foam pad under an inflatable to go colder. As a guide: R 2+ for summer, R 3–4 for spring and fall, R 5+ for camping on snow or frozen ground.
Heading out in the cold? Read our cold weather camping guide, and check what the wind will feel like with the wind chill calculator.
Frequently asked questions
What temperature sleeping bag do I need?
Choose a bag whose comfort rating is at or below the coldest low you expect, or about 10°F below it if you sleep cold. A 20°F limit-rated bag usually has a comfort rating near 30°F.
What R-value do I need for camping?
About R 2 for warm summer nights, R 3 to 4 for three-season camping with nights near freezing, and R 5 or more for winter and snow camping.
Is a 30 degree sleeping bag warm enough?
A bag with a 30°F limit rating is usually comfortable down to about 40°F for average sleepers. For nights near freezing, look for a 30°F comfort rating instead.
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