"Will this underquilt fit my hammock?" is the question we answer more than any other. The short version: most underquilts fit most hammocks, because nearly all camping hammocks share the same basic gathered-end shape — and even bottom-entry Hennessy Hammocks work with a universal underquilt (we just make a purpose-built option for them). Let's clear up one common sizing myth first, then go hammock by hammock.
Your underquilt doesn't need to match your hammock's size
The most common fit mistake is assuming a big hammock needs a big underquilt. It doesn't. An underquilt only needs to cover the section of the hammock you're actually lying in — not the full length and width of the hammock. Someone with a 132″-long hammock does not need a 132″ underquilt.
In fact, bigger is worse for fit. Once an underquilt gets wider than 48″ or longer than 86″, it becomes difficult to get a proper hang — it starts draping away from the hammock and opening the air gaps that cause cold spots. From decades of building and testing, for campers up to 6′5″ the sweet spot is about 42″ wide by 77″ long (the dimensions of our Mt Washington): plenty of coverage, and easy to hang tight with no gaps.
Gathered-end hammocks: the universal case
The vast majority of camping hammocks are gathered-end designs — the fabric bunches together at each end into a single suspension point. ENO, most Warbonnet models, Dutchware, Kammok, Hummingbird, and countless others all work this way. Because they share this shape, a standard "universal" JRB underquilt is built to cradle any of them.
If you have a gathered-end hammock, a universal underquilt like the Mt Washington 3 (20°F, three-season), the Mt Washington 4 (0°F, winter), or the lighter 3/4-length Greylock 3 will fit — it hangs beneath the hammock and clips to the end suspension. You don't need a hammock-brand-specific quilt. For reference, our owner (6′3″) runs a single Mt Washington on everything from 10′ to 12′ gathered-end hammocks.
Bridge hammocks: yes, a universal underquilt fits
Bridge hammocks use spreader bars for a flatter, wider lie, so people often assume they need something special underneath. They don't. Our Mt Washington fits our own James River Bridge hammock — and others like the Warbonnet RidgeRunner — on the included suspension, with full coverage on bridge and gathered-end hammocks alike. One universal underquilt covers both styles; no bridge-specific model required.
Bottom-entry Hennessy Hammocks: the Nest, or a universal quilt
Classic Hennessy Hammocks enter through a velcro slot in the bottom of the hammock instead of over the side. Here's the good news most people don't realize: a normal universal underquilt still works. You simply push it aside to climb in or out through the bottom slot, and the dynamic end suspension snaps it right back into place. It doesn't lock you out.
That said, we build the Nest (20°F) and Winter Nest (0°F) specifically for bottom-entry Hennessy models — shaped to work with the entry slot so you don't have to push anything aside at all. JRB introduced the first commercially available Hennessy underquilt, and the Nest is still the no-fuss, optimized pick. So: a universal underquilt works; the Nest just makes it effortless.
Hennessy's newer zip-entry models (like the Jungle Explorer Zip) behave like a standard gathered-end hammock, so a universal underquilt such as the Mt Washington 3 is a natural fit there too.
Full-length vs. 3/4 (torso) underquilts
Once fit is sorted, the other choice is length:
- Full-length underquilts cover you head to toe with zero thinking required — the safe, warm default, especially in cold weather.
- 3/4-length (torso) underquilts like the Greylock cover shoulders to knees and save weight for ounce-counting backpackers. You bridge the foot gap with a small pad, your pack, or spare clothing under your lower legs. (These use a channel suspension so you can position them exactly over your core.)
If you're not sure, go full-length.
Does an underquilt replace my top quilt?
No — they're two halves of the same system. An underquilt insulates everything beneath you, where your body weight would otherwise crush a top quilt or bag flat. A top quilt insulates everything above you. Plan on both. (A JRB multi-function quilt can play either role, which is handy if you also camp on the ground.)
Quick fit guide by hammock
| Hammock | Type | Underquilt to choose |
|---|---|---|
| ENO (DoubleNest, etc.) | Gathered-end | Universal (Mt Washington / Greylock) |
| Warbonnet Blackbird | Gathered-end (asym) | Universal |
| JRB James River Bridge | Bridge | Universal — Mt Washington on the included suspension |
| Warbonnet RidgeRunner & other bridges | Bridge | Universal |
| Dutchware Chameleon | Gathered-end | Universal (or the zip-on Chameleon quilt) |
| Hennessy (bottom-entry) | Bottom-entry asym | Nest / Winter Nest (no-fuss) — or a universal quilt (push aside to enter) |
| Hennessy (zip entry, e.g. Jungle Explorer Zip) | Zip entry | Universal |
| Kammok, Hummingbird, most others | Gathered-end | Universal |
Still not sure? It's an easy answer
Two things settle almost every case. First, confirm your entry style: over the side/top (gathered-end → universal), through a bottom slot (Hennessy bottom-entry → Nest), or a bridge with spreader bars (→ universal). Second, don't over-size — remember the underquilt only has to cover the section you lie in, so a ~42″×77″ quilt fits nearly everyone. If your hammock isn't listed above, send us the make and model and we'll confirm before you buy.
Three fit mistakes to avoid
- Buying an oversized underquilt to "be safe." Wider than 48″ or longer than 86″ is harder to hang and more prone to gaps — match the coverage to you, not to the hammock.
- Assuming a bottom-entry Hennessy rules out a universal underquilt. It doesn't — you push the quilt aside to get in and it snaps back. A Nest just removes that small step.
- Assuming a bridge hammock needs a special quilt. A universal Mt Washington fits bridge hammocks on the included suspension.
Getting the fit dialed once it's on
Matching the quilt to the hammock is step one; hanging it snug is step two. Even the right underquilt feels cold if it's left with a gap or cinched so tight it flattens the down. Our How to Hang a Hammock Underquilt guide covers the setup, the "lift the empty hammock" tension test, and how to close side and foot-end drafts.
You can't overheat — so size up
Whatever hammock you run, the temperature advice is the same: you can't overheat from an underquilt, because it only insulates beneath you. On a warm night you vent from your top quilt; there's no penalty for "too much" bottom insulation. So when you're between ratings, size up to the colder one — a 0°F Mt Washington 4 or Winter Nest on a mild night is just cozy, while an under-rated quilt on a cold night is a night you can't rescue from inside the hammock. See the Hammock Underquilt Temperature Guide for the full breakdown.
Find the right underquilt for your hammock
Gathered-end or bridge hammock? Any JRB universal underquilt fits. Bottom-entry Hennessy? A universal works (push it aside to enter) — or grab a Nest for a no-fuss fit. Still unsure? Message us — we've been building and field-testing hammock underquilts in the USA longer than anyone, and we'll match you to the right one. Shop hammock underquilts →