Underquilt Guide: How to Choose One

By topquilt.com · Updated Oct 21, 2026 · 6 min read

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An underquilt is the piece of hammock gear that makes hammock camping comfortable below summer temperatures. This underquilt guide explains what one does, how length, rating, fill and suspension affect your choice, and what to look for so you buy once. If you haven't read it yet, our hammock insulation guide explains why bottom insulation matters so much.

What an underquilt does

An underquilt hangs outside and underneath your hammock, held by shock cord or suspension lines. Your body presses the hammock fabric into the underquilt's loft without compressing it, because the underquilt itself carries no weight. That's why a 20°F underquilt can feel dramatically warmer than a 20°F sleeping bag lying inside a hammock: the bag's bottom insulation is crushed flat.

It pairs with a top quilt over you. Together they form the classic hammock sleep system. For how the two compare, see top quilt vs underquilt.

Full vs 3/4 vs partial underquilts

Length is the first decision and shapes everything else.

Figures are approximate and vary by maker and rating.

Full-length

Full-length underquilts are the easiest to use and the most forgiving. Your whole body is covered, nothing slides around, and you don't need to remember a pad. In cold weather they're the clear choice because legs and feet lose more heat than people expect. If this is your first underquilt, buy full-length.

3/4 length

A 3/4 underquilt covers from roughly your shoulders to below your knees. Your lower legs rest on a sit pad, a short piece of foam, or your empty pack placed inside the hammock. The legs need less insulation than the core, so this works well in three-season conditions. Taller users may find their shoulders or calves uncovered; check the length against your height and how you lie.

Partial or torso length

The lightest option. Used by ultralight hikers with a foam pad for legs, or as an add-on layer under a full underquilt in winter. Fiddly for most people and not ideal as a first underquilt. Our ultralight hammock setup page covers when it makes sense.

Choosing a temperature rating

Like top quilts, underquilts are rated by the manufacturer without a standardized test. Ratings are usually based on fill weight and loft and assume no wind, a well-adjusted fit and a top quilt that matches. Treat them as a rough guide; our underquilt temperature ratings page explains how to read them.

• Match your top quilt, or go warmer. Wind and small gaps affect underquilts more than top quilts. Many hammockers choose an underquilt 5-10°F warmer than their top quilt.
• Cold sleepers: add another 5-10°F of margin.
• One-underquilt quiver: a 20°F underquilt covers most of the US three-season range. In the Southeast, a 30-40°F model may be enough for most of the year.

Our hammock temperature guide has a full table pairing temperature ranges with top and bottom insulation.

Down vs synthetic underquilts

Down underquilts are lighter, pack smaller, and are the most common choice. Fill power of 800-850 is typical in cottage gear, with budget models often around 600-700. Synthetic underquilts (often Climashield APEX) weigh more and pack bigger, but they hold warmth better when damp and cost less. Underquilts hang closer to splash, ground humidity and blowing rain than top quilts, so synthetic is a reasonable choice in wet climates or for hammockers who often camp near rivers. See down vs synthetic and hydrophobic down.

Width and shape

Most underquilts are about 40-50 inches wide. Wider models wrap higher around your shoulders, which helps side sleepers and cold sleepers. Underquilts are typically either:

• Rectangular or slightly tapered, designed to hang under the hammock's centerline. The most common and the most universal.
• Differentially cut or asymmetric, shaped to match a diagonal lay. These can fit better but are tied to a lay direction.

If you use a bridge hammock, buy an underquilt made for it; bridge hammocks have a different shape and many gathered-end underquilts won't fit well.

Suspension features that matter

Most of the comfort of an underquilt comes from how well it seals against the hammock. Look for:

• Shock-cord end channels: gathered ends with adjustable shock cord that pull the underquilt snug at head and foot.
• Adjustable suspension lines: cord locks or line locks on each end, so you can raise, lower and slide the underquilt along the hammock. See underquilt suspension explained for shock cord vs static line.
• Side shock cord or "differential" channels: lets you snug the long edges up around your shoulders. Helps prevent side gaps.
• Hardware: mini carabiners or hooks for attaching to the hammock's end channels or suspension.

Our how to hang an underquilt guide explains how to use these to get a gap-free fit.

Shell fabrics and weather protection

Underquilt shells are usually 10D-20D nylon with a DWR finish. Lighter shells save weight but snag more on branches when you're setting up. If you camp in wind or blowing rain, an underquilt protector, a thin shell that hangs beneath the underquilt, cuts drafts and keeps spray off. A hammock sock does the same job and covers the top too; see top covers and hammock socks.

Do you even need an underquilt?

Not always. On warm summer nights above roughly 70°F, many people sleep fine with nothing underneath. And if you camp only occasionally, a sleeping pad inside the hammock does the job for far less money. An underquilt earns its price when:

• You camp regularly below about 60°F.
• You find pads uncomfortable or keep sliding off them.
• You want the full comfort benefit of a hammock, which is lying in the fabric without anything stiff beneath you.
• You're building a lighter kit; a down underquilt typically weighs about the same as a warm inflatable pad but feels much warmer in a hammock.

If you're not sure, start with a pad and see how often you hammock camp. Our sleeping pad in a hammock guide covers how to make that work.

Adding warmth to an underquilt you already own

Before buying a second underquilt for winter, try these:

1. Add an underquilt protector or hammock sock to block wind.
2. Add a closed-cell foam pad inside the hammock, on top of the underquilt.
3. Layer a partial underquilt beneath your full one for core warmth.
4. Improve the fit. A properly snug underquilt can feel 10°F warmer than a sagging one.

For true winter conditions, see winter hammock camping.

Common underquilt buying mistakes

• Underbuying warmth. A cold underquilt ruins sleep faster than a cold top quilt. When in doubt, go warmer on the bottom.
• Ignoring hammock compatibility. Check that the underquilt is made for your hammock length and style.
• Choosing partial for a first underquilt. Start full or 3/4 and go lighter once you know your preferences.
• Confusing fill power with warmth. Fill weight and loft determine warmth; fill power affects weight and packability. See fill power explained.

Where to buy

Cottage makers build the most refined underquilts and let you customize length, rating and colors. Hammock Gear, UGQ Outdoor and Warbonnet are long-standing hammock specialists, and Enlightened Equipment also makes underquilts. Expect lead times in busy seasons.

For a lower budget or faster delivery, several brands sell underquilts on Amazon. The Paria Outdoor Products Thermodown underquilt is a popular down option (check price on Amazon), and Onewind sells budget synthetic and down underquilts (check price on Amazon). ENO and Kammok also sell underquilts designed for their own hammocks. These are usually heavier for the same warmth than cottage gear, and their ratings can be optimistic, so allow extra margin.

Our current favorites across budgets are on the best underquilts page. Once you have one, pair it with a top quilt from the best hammock top quilts list.

Caring for your underquilt

Underquilts get dirtier than top quilts because they hang near the ground and collect dust, sap and spray. Spot-clean between trips, wash with a down-specific soap when loft drops, and store loose in a large storage sack. See how to wash a down quilt and how to store a quilt.