Sleeping Bag Rating Calculator
Find a recommended sleeping bag temperature rating from the expected overnight low. It adds a safety margin so your bag is rated below the conditions you face.
How to pick a bag rating
- Enter the expected overnight low in degrees Fahrenheit.
- Choose whether you sleep warm, average or cold.
- Read the recommended bag temperature rating.
- Compare it to the EN or ISO comfort rating on the bag.
Examples
Overnight low of 30 F, average sleeper
expected low 30 F, average sleeper
Margin -10 F, bag rated 20 F
Frequently asked questions
How do I choose a sleeping bag temperature rating?
Start from the coldest night you expect, then pick a bag rated below it. A safety margin covers cold sleepers, wind, damp and worn insulation.
What is the difference between EN/ISO comfort and limit ratings?
EN and ISO tests give a comfort rating, where most people stay warm, and a lower limit rating. Shop by the comfort rating, especially if you sleep cold.
Are these numbers exact?
No. This is a planning guideline. Real warmth depends on your pad, clothing, tent, humidity, wind and the bag's true tested rating.
Why do cold sleepers need a warmer bag?
People who sleep cold lose heat faster, so they need a bag rated below the expected low. The tool subtracts an extra margin for them.
Does my sleeping pad matter?
Yes, a lot. A pad's R value blocks heat loss to the ground. A warm bag on a thin pad can still feel cold, so match the pad to the conditions.
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