UD5 Toolkit
Sleeping Bag Comfort Rating Calculator – Online Personalize
Adjust a sleeping bag's EN rating based on sleeping pad R‑value, clothing, and personal warmth.
Sleeping Pad R‑Value Calculator – Online Temperature Matching
Sleeping Pad R‑Value Calculator
Match your sleeping pad's insulation to your camping temperature. R‑value measures thermal resistance — higher values keep you warmer on cold ground. Based on ASTM F3340 industry standards.
°C
-40°-30°-20°-10°0°10°15°
Insulation Spectrum
Warm
Summer 3-Season Cold
Weather Winter Extreme
Cold
Summer 3-Season Cold
Weather Winter Extreme
Cold
RECOMMENDED R‑VALUE
3.5
R
3-SEASON
Comfortable down to approximately -3°C (27°F)
≈ 1.75× foam pad (R~2.0)
Ideal for: Spring & Fall Camping
R‑Value Stacking Calculator — Combine two pads
When you stack two sleeping pads, their R‑values add together (ASTM F3340). Use this to see how much warmer you'll sleep with double insulation.
+
Combined R‑Value:
5.0
R
— Comfortable to approx. -18°C (0°F) WINTER READY
— Comfortable to approx. -18°C (0°F) WINTER READY
Popular Sleeping Pad R‑Values
| Sleeping Pad Model | R‑Value | Best For |
|---|---|---|
| Therm-a-Rest Z-Lite Sol (foam) | 2.0 | Summer / 3-Season |
| Sea to Summit Ether Light XT | 3.2 | 3-Season |
| REI Co-op Flash Insulated | 3.7 | 3-Season / Light Cold |
| NEMO Tensor Insulated | 4.2 | Cold Weather |
| Therm-a-Rest NeoAir XLite NXT | 4.5 | Cold / Light Winter |
| Big Agnes Insulated Air Core Ultra | 4.5 | Cold / Light Winter |
| Exped Ultra 5R | 4.8 | Winter |
| Therm-a-Rest NeoAir XTherm NXT | 7.3 | Extreme Cold / Mountaineering |
| Exped Ultra 7R | 7.1 | Extreme Cold |
Note: R‑values tested per ASTM F3340. Always check manufacturer specs for your specific model year.
Quick Tips
- Stack pads to boost R‑value: Rtotal ≈ R1 + R2
- Use a closed-cell foam pad under an inflatable for extra warmth & puncture protection.
- Ground matters: Snow conducts heat 100× faster than dry soil. Add +0.5 to +1 R on snow.
- Your sleeping bag rating assumes you have an adequate pad (usually R≥4 for winter bags).
- Cold sleeper? Add 0.5–1.0 R above the standard recommendation.
- Inflatable pads lose some R‑value when under-inflated — keep them fully inflated in cold.
Frequently Asked Questions
What is a sleeping pad R‑value?
R‑value measures a pad's resistance to heat flow — its ability to insulate you from the cold ground. Higher numbers mean better insulation. It's the same scale used for home insulation, tested under ASTM F3340 for sleeping pads.
What R‑value do I need for winter camping?
For winter camping (below -6°C / 20°F), you need an R‑value of 4.5 to 7+. For extreme cold below -18°C (0°F), aim for R ≥ 6. Many winter campers stack two pads to achieve this.
Can I stack two sleeping pads?
Yes! R‑values are additive when pads are stacked. A foam pad (R=2.0) plus an inflatable (R=3.5) gives you R=5.5 combined — a cost-effective way to extend your gear into colder seasons.
Is R‑value the same as temperature rating?
No. R‑value is a physical measurement of insulation. Temperature comfort depends on many factors: your metabolism, ground type, sleeping bag, clothing, humidity, and wind. Use R‑value as a guideline, not an absolute guarantee.
What R‑value for summer camping?
For summer camping (above 5°C / 41°F), an R‑value of 1.0 to 2.5 is usually sufficient. Ultralight pads or simple foam pads work well. Some hikers even use uninsulated air pads (R~1) in warm conditions.
How accurate is the ASTM F3340 standard?
ASTM F3340 is the industry-standard test that measures a pad's R‑value in a controlled lab environment. It's highly repeatable and allows direct comparison between brands. Most major manufacturers now use it.
Do foam pads have lower R‑values than inflatables?
Not necessarily. While basic foam pads (R~2) are less insulating than premium inflatables (R~4-7), thick closed-cell foam can achieve R~3-4. The advantage of inflatables is their higher R‑value-to-weight ratio.
Why does my sleeping bag need a good pad?
Your body weight compresses the sleeping bag's insulation underneath you, rendering it nearly useless against ground cold. The sleeping pad is your primary barrier against conductive heat loss to the ground — it's just as important as your bag.
R‑value guidelines based on ASTM F3340. Actual comfort varies by individual metabolism, ground conditions, and gear combination. Always test gear before remote trips. When in doubt, bring a warmer pad.
Horse Blanket Weight Selector – Online Temperature & Coat Checker
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10 Essentials Hiking Checklist – Online Interactive Pack List
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Camping Gear Checklist – Online Custom by Trip Type
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Insulation R-Value Calculator - Online Building Thermal Envelope Tool
Compare insulation materials and thicknesses to achieve a target R-value. Understand U-factor. Educational home improvement tool. Local.