Fellkit

Nemo

Nemo Forte 20 Endless Promise Synthetic Sleeping Bag (Men's Regular)

Where it fits

Not for
Winter mountain
Why these labels
  • Winter mountain: Comfort rating -2 °C: too cold for winter nights

From the maker's stated use and the published specs.

  • Summer wild camp: 5/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
  • Three-season hills: 6/10 UK hills in spring and autumn. Wind, rain, and nights near freezing.
  • Winter camp: 4/10 UK winter or high ground. Below freezing, strong wind, possibly snow. Capped at 4: needs warmth 9+ (comfort -5 °C or colder).
  • Weight: 3/10 How much it adds to your pack, compared with the whole market.

Comfort -2 °C, limit -8 °C (ISO 23537).

Lowest price we found

£173.95 at Absolute Snow

In stock. Free delivery. Checked 8 Nov 2026.

RRP £219.95, checked 18 Oct 2026.

Go to Absolute Snow

Side sleepers and restless sleepers who find mummy bags too tight

Comfort
-2 °C
Limit
-8 °C
Fill
synthetic
Weight
1.5 kg (Regular)
Packed size 10.6 L, 46 cm long and 24 cm across Compare with a 2-litre bottle

About one and a half 2-litre bottles long and about two and a half times as wide. Drawn to scale.

Where to buy

Absolute Snow £173.95 In stock. Free delivery.

View at shop: Absolute Snow

Snow+Rock £159.95 Out of stock.

View at shop: Snow+Rock

Prices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More

Our ratings (out of 10)

1 to 10, compared with the whole market. Each says what it's based on. How we score

Warmth

From maker's figures 7/10

How cold a night you can sleep comfortably through. 7: Better than most.

Nemo's ISO comfort figure of -2 °C sits in the -4.9 to 0 °C band; the limit is -8 °C, so it is a three-season bag, not a true -7 °C one.

Room inside

Estimate: only 2 reviews about room inside (fewer than the 3 we need, so never above 8) 8/10

How much room to move, bend your knees and sleep on your side. Roomier is comfier. 8: Clearly better than most.

Reviewers describe the Forte as clearly roomier than a normal mummy, with extra space at the knees and elbows that suits side sleepers and restless sleepers. Two sources only.

Weight

From maker's figures 3/10

How much it adds to your pack. 3: Below average. Fine for some trips, not others.

Nemo's minimum weight of 1.5 kg sits in the 1,300–1,699 g band.

Packed size

From maker's figures 4/10

How much room it takes in your rucksack. 4: A bit below average.

Nemo states a compressed volume of 10.6 L, in the 9–12.9 L band; but the 46 x 24 cm stuff sack works out larger: 3.1416 x 12 x 12 x 46 = 20,810 cm³, about 20.8 L.

What reviewers say (out of 10)

Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score

Comfort to sleep in*

Reviewers' average 9/10

How comfy the shape, hood and fabric feel; not the temperature rating.

3 reviews on comfort, e.g. "the bag felt snug enough to retain warmth around my shoulders and hips without ever feeling restrictive".

Zip*

Estimate: only 2 reviews about the zip (fewer than the 3 we need, so never above 8) 8/10

How smoothly the zip runs without snagging.

2 reviews on the zip, e.g. "smooth-operating zippers, clean stitching, and no visible wear".

In short

Good for

  • Side sleepers and restless sleepers who find mummy bags too tight
  • Spring-to-autumn UK camps where weight and pack space matter less than room to move
  • Campers who want a synthetic bag that still works if it gets damp

Strengths

  • Roomy shape gives space for knees and elbows without feeling like a rectangular bag
  • Synthetic fill, so it keeps working if it gets damp from a wet tent
  • Zip-open vents and a big draft collar let you cool down or warm up without getting out of the bag
  • Built-in pocket holds a pillow or a rolled-up jacket in place

Weaknesses

  • Heavy and bulky for a bag at this temperature, so it is a poor choice for long walks with a full pack
  • The -2 °C comfort figure is the realistic one to use: it is not a true -7 °C bag, and the roomy cut can leave cold spots for some sleepers
  • The small vent zips feel less refined than the rest of the bag
  • The packed sack (46 x 24 cm) is bigger than the 10.6 L maker figure suggests
  • One reviewer of the earlier version found the big draft collar rode up over their face at night

Sources

We haven't tested this ourselves. Every score comes from these specs, tests and reviews.

ShowHide sources (6)
  1. Nemo: Forte Men's Endless Promise 20F Regular specifications Specs, 18 Oct 2026. Used for: warmth, weight, packed size
  2. Better Trail: Nemo Forte 20 sleeping bag review Review, 18 May 2026. Used for: room inside, comfort to sleep in, zip
  3. Live for the Outdoors: Nemo Forte 20F synthetic sleeping bag, tested and reviewed Review, 20 May 2025
  4. Live for the Outdoors: Nemo Forte 20F synthetic sleeping bag review Review, 20 May 2025. Used for: room inside, comfort to sleep in
  5. Outdoors Magic: Nemo Forte sleeping bag review Review, 26 Oct 2022. Used for: comfort to sleep in
  6. Treeline Review: NEMO Forte Endless Promise sleeping bag review Review, 10 Apr 2024. Used for: zip