Underquilt Sizing Guide

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

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Underquilt sizing is less about your body than about how the underquilt fits the hammock. The underquilt has to wrap the hammock's underside snugly from your head to your feet (or shoulders to knees for a 3/4), and that depends on hammock length, hammock style and how you lie in it. Get the size right and adjusting the hang becomes easy; get it wrong and you'll fight gaps all night. For choosing the rest of the underquilt, see our underquilt guide.

Underquilt lengths, explained

Exact lengths vary by maker and by whether they measure the shell, the insulated area or the length including end channels. Check the listing. For the 3/4 vs full decision, see full vs 3/4 underquilt.

Why underquilt length doesn't simply equal your height

In a gathered-end hammock you lie on a diagonal, and the underquilt hangs along the hammock's centerline. Your head and feet end up off to opposite sides of center. A full-length underquilt therefore needs to be long enough that, measured along the hammock, it extends past your head and feet on that diagonal. In practice, a regular full-length underquilt covers people up to about 6 feet, and a long version covers taller hangers.

Ends matter too. Many underquilts have drawcord end channels that cinch around the hammock. When cinched, the ends gather and lose a few inches of effective length. That's why a 76-inch underquilt doesn't feel like 76 inches of loft under you.

Underquilt width

Width determines how high the underquilt wraps up the sides of the hammock, which affects your shoulders, arms and side-sleeping comfort.

Some makers quote the width at the widest point of a tapered underquilt, others the width of the insulated area. A wider underquilt adds roughly 1-3 oz depending on fill. It also gives more margin when the underquilt shifts during the night. Hangers on wide hammocks (around 60 inches or more of fabric width) often benefit from a wide underquilt so it can reach high enough on the sides.

Hammock length compatibility: gathered-end hammocks

Gathered-end hammocks are the most common style, and most standard underquilts are designed around them. Longer hammocks give a flatter lay, which also affects underquilt fit.

These height ranges are rough community guidance, not rules. Many shorter people prefer 11 ft hammocks for the flatter lay, which is fine: the underquilt suspension adjusts along the hammock's length. What matters is that the underquilt covers you, and that its suspension reaches the hammock ends. More on hammock styles in gathered-end vs bridge hammock.

Suspension reach

Most underquilts hang from shock cord or line that runs from the corners or ends to the hammock's gathered ends or suspension. On a 12 ft hammock, the distance from underquilt end to hammock end can exceed the built-in cord. Owners typically add a short extension of shock cord or line, or use an adjustable suspension. Our underquilt suspension explained page covers the common systems and how to lengthen them.

Bridge hammocks need bridge underquilts

Bridge hammocks use spreader bars at each end to hold the bed open into a flatter, more rectangular shape. You lie straight along the hammock rather than on a diagonal. A standard gathered-end underquilt is cut for a curved, tapering underside and tends to gap at the sides and corners of a bridge.

Bridge-specific underquilts are shorter (the bed itself is shorter than a gathered-end hammock, often around 75-90 inches between spreaders), cut to the bridge's shape, and attach to the spreader bars or the bridge's suspension. Many bridge makers sell matching underquilts, and some third-party underquilts list bridge compatibility. See best bridge hammock underquilts.

Integrated and asymmetric hammocks

Some hammocks have a built-in footbox, an offset lay or asymmetric cut. Warbonnet's Blackbird line is a well-known example, with underquilts designed to match. Our Warbonnet Yeti review covers how a hammock-specific underquilt is shaped. Hammocks with integrated bug nets or zippers generally work with standard underquilts, though you may need to route suspension around the zipper.

Sizing for tall hangers

Tall hangers (about 6'2" and up) face three problems: underquilts that end at the calves, hammocks that are too short for a flat diagonal lay, and suspension that won't reach. In order of priority:

1. Get a long enough hammock. An 11-12 ft hammock gives room for a flat diagonal. A short hammock forces a curved lay that no underquilt can fix.
2. Choose a long underquilt. Many cottage makers, including Hammock Gear and UGQ Outdoor, offer long lengths or custom builds. See our Hammock Gear Incubator review for one example of the sizing options.
3. Consider wide too. Tall people often have broader shoulders, and a wide underquilt reaches higher.
4. Check the suspension reach. Add extensions if needed.
5. Don't rely on a 3/4. It covers less of a long body, leaving more of your legs on a pad.

For top quilt sizing on the same body, see quilt width and length sizing.

Quick sizing chart by height

Rough guidance only; your build, sleep position and hammock all play a part.

Signs your underquilt is the wrong size

• Cold feet or head with a full-length quilt: too short, or hung off-center. Try sliding it toward the cold end first.
• Cold shoulders or arms: too narrow, or hung too low. Raise it or consider a wider model.
• Gaps along the sides no matter how you adjust: the cut doesn't suit your hammock (common with bridges or very wide hammocks).
• Suspension at full stretch and still loose: needs extension cord, not a different quilt.
• Underquilt bunches at the ends: too long for a short hammock; cinch the end channels tighter.

Most of these are fixable with adjustment before you resort to a new quilt. Walk through how to hang an underquilt and cold butt syndrome first.

Measuring your own setup before you buy

If you already own a hammock, ten minutes of measuring avoids most fit problems:

1. Measure the hammock's fabric length from gather to gather (not including the suspension). This tells you whether you're in 10, 11 or 12 ft territory, since some hammocks are sold by finished length and others by fabric length.
2. Hang it at your normal sag (about a 30° hang angle is the usual starting point) and lie in it on your preferred diagonal.
3. Have someone mark where your head and heels are along the underside, or reach under and feel for them. The distance between those points, measured along the hammock, is the minimum insulated length you want for a full-length underquilt, plus a few inches for the cinched ends.
4. Note how high your shoulders sit on the sides. If they rise well up the walls of the hammock, a wide underquilt will reach them better.
5. Measure the distance from the gathered ends to where an underquilt's ends would sit. Compare it with the maker's suspension length to see whether you'll need extensions.

Send these numbers to the maker if you're between sizes. Custom-built underquilts from cottage brands can usually be adjusted in length or width for a modest upcharge and a longer wait.

Sizing protectors, top covers and pads

Accessories need sizing too. An underquilt protector should be slightly larger than the underquilt so it doesn't compress the loft; most are sized for 10-11 ft hammocks. Top covers are sized by hammock length. If you're pairing a 3/4 underquilt with a pad, a pad of about 20 inches wide and 20-30 inches long under the legs is enough; a cut-down foam pad works well, or try a short foam pad such as the Therm-a-Rest Z Lite Sol in a short size (check price on Amazon).

Bottom line

For the typical hanger on a 10-11 ft gathered-end hammock, a regular full-length underquilt in standard width fits. Size up to long and wide if you're tall, broad or a side sleeper, and buy a bridge-specific underquilt for a bridge hammock. When in doubt, ask the maker; cottage brands are usually happy to advise on fit. Current picks are on the best underquilts page.