A backpacking or camping sleeping pad’s R-value measures its resistance to heat loss to the ground when you lie on it at night. Pads with higher R-values do this more effectively than pads with lower R-values. R-value isn’t a measure of warmth per se, but of a pad’s ability to prevent the loss of the warmth that your body generates. It’s just like the R-value used to rate home insulation.

Correlation Between R-Values and Air Temperature

What’s the correlation between air temperature and sleeping pad R-values? When do you need a pad with a higher R-value? This table is based on Exped’s recommendations in Fahrenheit and Celsius degrees.

In addition:

• R-values are additive, so you can combine two pads to increase your warmth level. For example, it’s common to carry a foam sleeping pad (usually R=2) in winter to use as a sit pad when eating and melting snow that you can place under an inflatable pad to increase its combined R-value for sleeping.
• Women need higher R-value pads because they have lower body mass than men. An additional R-value of 1 is usually a good hedge for women and other cold sleepers.
• If a pad model has multiple sizes, they all have the same R-value unless specified otherwise
• Sleeping bag temperature ratings are predicated on using a sleeping pad with an R-value of 5 or higher. If you find yourself sleeping cold in temperatures where you’d expect your sleeping bag should keep you warm, it may be because your sleeping pad has an R-value less than 5.

Sleeping Pad R-Value Comparison

The following table provides a side-by-side comparison of the ASTM F3340-18-rated sleeping pads available in the US market. The pad weights listed are for 72″ x 20″ pads, though there are a few exceptions below. The R-Value of a pad remains the same if you select a longer, shorter, or wider variation of the pad.

Key: Air – Air Mattress, SI – Self Inflating, Foam – Closed Cell Foam

Sleeping Pad R-Value Standard

In 2020, the outdoor industry adopted an international, industry-standard R-value test procedure, ASTM F3340-18. This means you can compare the R-values of sleeping pads made by different manufacturers and know they’re all using the same test procedure. That’s a huge benefit for consumers and will eventually have the same impact that the adoption of standardized sleeping pad temperature ratings had for comparing sleeping bags from different companies.

The companies that have adopted the new R-value sleeping pad standard (ASTM F3340-18) and retested all of their current sleeping pads include:

• Therm-a-Rest
• NEMO
• REI
• Exped
• Sea-to-Summit
• Big Agnes
• Klymit
• ZenBivy

What’s New in Camping Sleep Insulation in 2026?

• Manufacturers are making a lot more self-inflating pads, presumably for the overland and car camping segments, because they’re way too heavy to carry in a backpack.
• Klymit continues to churn out low-R-value pads, but they’re now ASTM F3340-18 rated, so they’re comparable to other premium sleeping pads and can be sold by REI, which requires that they be tested in an independent test lab.

Status of Industry Adoption

The adoption of the new R-Value standard was driven by REI, which requires that the sleeping pads listed for sale on its main website have an ASTM F3340-18 R-Value rating.

Many sleeping pad companies have still not adopted the new ASTM F3340-18 sleeping pad R-Value standard, and it’s not clear that they ever will. In fact, many manufacturers don’t test their pads at all, but “estimate” the R-values of their sleeping mats and pads. In the absence of a standard definition and test procedure, it’s hard to tell whether their estimates are accurate or comparable to those produced by the ASTM F3340-18 R-value testing protocol. Buyer beware.

Updated Jan 19, 2026

See also:

• Foam Sleeping Pads vs Inflatable Pads on the Appalachian Trail
• Why Do Backpackers Use Foam Sleeping Pads?
• New Sleeping Pad R-Value Standard FAQ: ASTM FF3340
• 10 Best Backpacking Sleeping Pads
• Backpacker Sleeping Pad Preferences: Inflatable Air Pads Dominate

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