Full vs 3/4 Underquilt

By topquilt.com · Updated Oct 21, 2026 · 7 min read

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Underquilts come in three broad lengths: full (head to feet, roughly 72-80 inches), 3/4 (shoulders to knees, roughly 48-56 inches) and partial or torso-length (roughly 36-45 inches). This page focuses on full vs 3/4 underquilt choices, because that's the decision most hammock campers face. We work through the real weight math, the best ways to insulate your legs, and who each length suits. For the bigger picture on choosing any underquilt, see our underquilt guide.

Full vs 3/4 underquilt: side-by-side

The weight math, worked out

Underquilt weight scales roughly with area, because the fill and fabric are spread across the whole quilt. Take a typical 20°F 850 fill-power down underquilt as an example. These are illustrative figures based on common maker specs, not a specific model:

• Full-length, ~78 x 45 in: about 22 oz
• 3/4 length, ~52 x 45 in: about 16 oz
• Saving: about 6 oz, or roughly 27%

Now add what you'll put under your legs:

The temperatures are rules of thumb, not tested figures; they assume a well-rated top quilt and decent sleep clothing. The lesson is clear: a 3/4 underquilt only saves meaningful weight if your leg insulation is something you're carrying anyway. If you'd buy and carry a dedicated pad just for your legs, the saving shrinks to a couple of ounces or disappears.

Why legs can get away with less

Your core (chest, back, hips) produces and loses the most heat, and it's where cold spots wake you up. Lower legs have less surface heat flow per square inch and are usually covered by the top quilt's footbox anyway. That's why a 3/4 underquilt plus a modest leg pad works for many sleepers.

The exception is people who get cold feet. If you already sleep in socks in summer, your heels sitting on a thin pad will be your first cold spot. For you, the full-length underquilt is worth the ounces. Our quilts for cold sleepers guide covers other ways to stay warm.

Pairing a pad with a 3/4 underquilt

Getting the leg pad right makes the difference between a 3/4 setup that works and one that you abandon after a trip.

1. Position the underquilt first. The top edge should sit at or just above your shoulders, with the bottom edge just past your knees when lying on your diagonal.
2. Place the pad inside the hammock, under your calves and heels. Slightly overlap the underquilt's bottom edge so there's no bare strip behind your knees.
3. Stop it sliding. A double-layer hammock or a sleeve keeps the pad in place. On single-layer hammocks, tuck it under the top quilt's footbox or use a short piece of shock cord.
4. Use something with closed cells below 40°F. A pack has almost no insulation value once compressed. A foam sit pad like the Therm-a-Rest Z Seat (check price on Amazon) weighs very little and doubles as a camp seat.

For more on pads in hammocks generally, see sleeping pad in a hammock.

Asymmetric and diagonal-cut 3/4 underquilts

Some 3/4 underquilts are cut on a slight diagonal or asymmetric pattern to match the way you lie across a gathered-end hammock. Warbonnet's partial and 3/4 designs are the best-known examples; our Warbonnet Yeti review covers how a hammock-specific 3/4 underquilt is shaped. These cover more of where you actually lie for the same weight, but they're usually tuned to a particular hammock. On other hammocks they can work, with some trial and error.

Standard rectangular 3/4 underquilts are more universal. They hang centered, and you shift your hips and shoulders into the middle.

Full-length underquilts: when the extra ounces pay off

• Below freezing: cold heels are hard to fix in the night. Most dedicated winter underquilts are full length for this reason.
• Tall hangers: a 3/4 underquilt covers less of a 6'3" body, so more of your legs are on the pad. Consider long full-length models; see the underquilt sizing guide.
• Side and restless sleepers: rolling and drawing your knees up move your legs around more than a small pad can follow.
• Simplicity: no pad to place, no gaps between pad and quilt. Set it once and sleep.
• Hammock lounging: sitting sideways in the hammock in camp is warmer with full coverage.

A benchmark full-length option is covered in our Hammock Gear Incubator review.

3/4 underquilts: who they suit

• Ultralight and thru-hikers who carry a sit pad and frameless pack anyway.
• Three-season hangers whose nights stay above about 30°F.
• Warm sleepers whose legs rarely feel cold.
• Shorter hangers, for whom a 3/4 covers close to full length.
• Budget-minded buyers, since 3/4 versions often cost less for the same rating.

Our best 3/4 underquilts roundup compares current options.

What about partial (torso) underquilts?

Torso-length underquilts of around 36-45 inches cover shoulders to hips only. They're mostly a summer or supplemental tool: pair one with a full-length pad, or use it with a pad underneath for an ultralight three-season kit. Below about 45°F, most people find the gaps at both ends make them fussy.

Hang tips that matter more with a 3/4

A full underquilt is forgiving: it covers everything, so slight misplacement still leaves you insulated. A 3/4 underquilt has two edges near warm parts of your body, so placement matters.

• Slide the underquilt toward your head end until the top edge wraps your shoulders. Cold shoulders are the most common 3/4 complaint.
• Use end-channel cinches to close the ends so cold air doesn't flow in under your shoulders.
• Lie in the hammock and adjust; an underquilt that looks right with an empty hammock often shifts once you're in.

Our how to hang an underquilt guide and underquilt suspension explained go through this in detail.

Common 3/4 setup mistakes

Most complaints about 3/4 underquilts trace back to a handful of avoidable errors rather than the length itself.

• Relying on a pack below 40°F. A frameless pack crushed under your calves has almost no loft left. It's fine on mild nights, but once the temperature drops into the 30s°F it stops being insulation and becomes a cushion.
• A gap behind the knees. If the leg pad starts a few inches below the underquilt's bottom edge, you get a cold band right where your hamstrings rest. Overlap the two by 2-4 inches.
• Hanging it centered on the hammock. A 3/4 underquilt should be centered on you, which usually means shifted toward the head end, since your torso is closer to the head end than the middle of the hammock.
• Forgetting the top quilt's footbox. With a 3/4 setup, your feet rely on the footbox above and the pad below. A loose or open footbox lets heat escape where you have the least insulation. Cinch it closed on cold nights.
• Choosing the wrong rating to compensate. Some buyers pick a warmer 3/4 to make up for cold legs. Extra loft under your torso doesn't warm your feet; fix the leg insulation instead.

Switching later: buying one length now, another later

Many hammock campers end up owning both. A common path is a full-length three-season underquilt bought first, then a light 3/4 or partial underquilt for summer and fast-and-light trips. The two can also be stacked in the shoulder seasons: a 40°F 3/4 hung under a 20°F full-length underquilt adds warmth exactly where your core needs it. If you expect to go that route, buy the full-length quilt first. It's the more versatile single piece, and the 3/4 becomes a cheap add-on rather than your only option on a cold night.

Verdict

If you're unsure, buy full length. It's the more forgiving choice, it works in more conditions, and the weight penalty is only a few ounces once you count the leg pad. Shortlists for both are on our best underquilts page.