Big Agnes Onyx Ultralight Tarp Review

Big Agnes Onxy Tarp Review

Big Agnes’ Onxy Tarp is a square tarp designed for ultralight backpacking and bikepacking. Weighing 8.1 oz, it’s seam taped and fully outfitted with guy lines and tensioners out of the box, so you don’t have to buy anything extra to start using it. The tarp also includes a short pole which is useful for pitching the shelter if you don’t carry trekking poles and can also serve as a spreader bar to create more headroom if you use the use the tarp with a hammock or for two people. Tarp camping is ideal if you want to minimize the weight and bulk of your gear for ultralight backpacking or bikepacking.

Big Agnes Onyx Ultralight Tarp

Packed Size

Super Lightweight

The Big Agnes Onyx is easy to use and can be set up in multiple configurations. Its light weight, compact size and versatility make it ideal for backpacking, hammocking, and bikepacking.

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Specs at a Glance

  • Type: symmetric square tarp
  • Weight of tarp: 8.1 oz (including guylines, cord tensioners)
  • Weight of optional pole/spreader bar: 1.6 oz (length – 40.5″)
  • Dimensions: 8’6″ x 8’6″
  • Number of guy-outs (5 per side), 16 total
  • Material: PU coated, silicone-treated nylon ripstop, 1200mm
  • Seam-taped: Yes

The Onyx is a square tarp meaning that the sides have equal length and the corners are right angles. Square tarps are relatively rare compared to rectangular tarps or catenary cut tarps which have curved ridgelines or edges to save weight and reduce flapping. Square tarps are however wonderfully versatile and can be configured in all kinds of different pitches or shapes, although it requires considerable practice and skill to make them. Most of the time, people still set them up in an A-frame configuration, which is easy to master, and very fast to set up.

The corners and center guyout points have additional Hypalon tabs that are cut to accept the accessory pole : spreader bar
The corners and center guy out points have additional Hypalon tabs that are cut to accept the accessory pole / spreader bar.

While the Onyx is made with PU coated silicone treated nylon, it is still very lightweight, even when compared to a similarly sized square tarp made with Dyneema Composite Fabrics (formerly called cuben fiber). It also stuffs up quite small, a bit smaller than a Nalgene bottle, making it very easy to carry in a low volume ultralight backpack or in a bikepacking bag, where space is at a real premium.

All of the guy out points on the Onyx are made with short lengths of green webbing which is box-tacked and reinforced on the seam, in addition to external panel guy outs to help expand interior volume. The corners and centers guy outs on each side also have separate Hypalon tabs, also box-tacked to the hems, that are laser cut to accept the optional pole tip. There are four additional Hypalon tabs attached to the interior panels of the tarp, that can accept the tips of the spreader bar, if you want to increase interior volume. This can be especially helpful if you use the Onyx as a hammock tarp (on the diagonal) or as an A-frame shelter for two people.

The pole can also be used as a spreader bar if you use the Onyx as a hammock tarp or to provide more headroom for two people
The pole can also be used as a spreader bar if you use the Onyx as a hammock tarp or to provide more headroom for two people

The Onyx comes pre-guyed with lightweight cord and triangular guy line runners, so you can start using the tarp right away without having to outfit it. The center seam is also taped, so there’s no seam sealing required.

Comparable Square Tarps

Make and ModelDimensionsWeightMaterialPrice
Big Agnes Onyx Tarp8'6" x 8'6"8.1 ozsilPU$280
Hyperlite Mountain Gear8'5" x 8'5"8.85 ozDCF$355
Mountain Laurel Designs Supertarp10'x10'19 ozsilnylon$245
Yama Mountain Gear8'5" x 8'5"13.9 ozsilpoly$140
Rectangular tarps can be pitches in many different ways depending on weather conditions and how much space you have
Square tarps can be pitched in many ways depending on the weather and how much space you have. They also take up minimal space when packed.


The Big Agnes Onyx Tarp is an ultralight square tarp that can really hold its own in terms of price, gear weight, and versatility, even when compared to ultralight tarps made by cottage manufacturers. Suitable for backpacking, hammocking, and bikepacking, the square Onyx is large enough for use by one or two people and even includes an optional pole for setup if you don’t carry trekking poles. It’s also outfitted for immediate use with a seam-taped ridgeline, guy lines, and line runners, which is a nice touch you don’t often see when purchasing a tarp and adds a lot of value.

Big Agnes provided a tarp for this review.

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  1. Bill in Roswell, GA

    As nice a package as it is, the price is absurd. A flat tarp for the same price as a catenary cut, tub floor, insect screened tent made in the USA (Tarptent and others). No thanks.

    My $70, flat 10×10 tarp can do everything the Big Agnes tarp can for only a few ounces more. The Big Agnes setup is worth $150 at most.

    • I actually think this is a really sweet UL tarp. You’ll be hard pressed to find anything this lightweight no matter what it’s made with. My guess is that your 10 x 10 is a lot heavier than 8.1 oz, even without it’s guy lines.

    • Dude there’s no way that a $70 flat 10×10 is only “a few ounces” more than 8.1 ounces. I have a 10×10 tarp that was more than $70 made from (really light!) silnylon and it weighs about a pound. A 10x10ish cuben tarp would be, literally, “a few ounces” more than 8. MLD’s isn’t even quite 10×10 and it weighs 11 ounces and costs almost $400!

      8.1 ounces is pretty absurdly light for a tarp of this size, especially considering it includes guylines and tensioners. I’m with BCap that we seem to be getting awful close to almost unbelievable weights. Really curious about the long-term durability of this fabric.

      Philip – this being silPU-treated nylon, any thoughts on the stretch (both generally and when it gets wet) and conjectures on durability?

      • The stretch is almost identical to regular silnylon. I don’t consider it an issue. As for durability, there’s very little wear and tear on a tarp like this. It rarely touches the ground and you don’t lie on it. I wouldn’t worry about that either.

      • I made a 9×7 silpoly that weighs 10.5 oz fully rigged so I think Bill isn’t misleading us. Spreader bar is p cool though

  2. That spreader bar is a pretty cool idea. I’ll have to see if I can retrofit a tarp without holing it.

  3. You say the guyouts are bar tacked, but the picture seems to show a narrow box tack. Are the interior tags also tacked (i.e. could the tarp be flipped and those used as additional guy points?

    I think the price is steep for unknown durability and long term waterproofing, but it certainly seems to be well thought out and the weight is insane for not being DCF.

    • You are correct. They are box tacks. the interior tags are also box tacks, but so are the external panel guy out points..

  4. Thanks for the review. I like the spreader bar addition.

    Daughter #2 asked for a tarp for use as an adjunct to add “dry” space for a rainy campsite, I said OK, and made her a 9’8″x 11’8″ 1.1 oz. silicone treated polyester flat tarp with four 8′ corner tie outs, two 12′ ridge tie outs, and six more loops for tie outs on the side edges. It weighs 18 oz. In robins egg blue–OMG it’s such a beautiful color, pictures don’t do it justice. Cost: under $70 and two hours. Waterproofed with silicone/paint thinner mix. A capable sewing machine costs about $100-150–this project doesn’t require a commercial unit.

    For the $280 price of the Big Agnes tarp, you could buy a sewing machine and everything needed to make any size tarp and in many color choices, and have $$ left to jingle in your pocket! Everyone else, buy it by clicking on the link above.

    • You’d be hard pressed to find the fabric used by BA to make this tarp. It’s not something that’s widely available. I figure they had a special batch made.

      • OK so I can’t get the same fabric, but BA doesn’t offer Robins Egg Blue. BA’s website shows:
        Specs + Sizing
        Trail Weight 10oz / 283g
        Packed Weight 14oz / 397g
        Fast Fly Weight 8oz / 227g
        Floor Area 72 sq ft / 6.7 m²

        Define “Fast fly weight” for a tarp? BA defines Trail weight: “the weight of the tent components necessary for setup and function” Then it includes tarp, lines (and ?)
        That 72 sq ft (=8 sq yards) is consistent with a weight under 1 oz per sq yd., a bit under the 1.1 oz sil poly sold online.

        My daughter’s tarp: almost 120 sq ft=13.33 sq yd. weighing 18 oz (on my OXO scale) WITH six 1/16″ nylon lines. A homemade 8.5 x 8.5 1.1 oz silpoly tarp pencils out to 8.83 oz before tie outs, which add 1-3 oz depending on what lines I use. BA has lighter weight fabric, but the waterproof rating on our silpoly is 2000mm. Is the Onyx with only one color choice worth $280? Maybe if you want to eliminate every ounce possible at any cost, if you love that silver color or if you can get it in Robins Egg Blue. If you earn $$$ or don’t need to save for retirement, don’t have the time to sew or can’t learn to sew, then, yes, buy it. Scroll up and click on the link.

        Robins Egg Blue. We are astounded.

      • Ignore their specs. That’s why I measure and weigh stuff myself. Note the specs at a glance section above.

  5. ZPacks 8.5′ x 10′ Rectangular Tarp is 6.4oz and $275.

    Larger, cheaper, and lighter!

    Is there any reason to choose the BA tarp over the ZPacks one?

    • It’s not a square tarp. Square tarps are more Versatile than rectangular ones. They take more skill to use, but they are a lot more fun to pitch.

      • I guess I’ve only used rectangular tarps, and I haven’t ventured much beyond a-frame and half-pyramid pitches, so I don’t really understand the nuances of pitching a square tarp.

        What can you do with an 8.5′ x 8.5′ tarp that you can’t do with an 8.5′ x 10′ tarp?

        I definitely get the fun of pitching a tarp, so if there’s some special magic to a square that’s even more fin, I might have try making one to try it out!

        try these.
        For forested pitches, it’s far better to have a square with equal sides/long guylibe to reach between trees than a rectangle. You can make it into non-rectangular, organic shapes much more easily.

  6. Cuben/Dyneema have somewhat plateaued in weight and price but nylon still continues to make surprising progress that I would not have expected 5-10 yr ago. This is a BIG tarp and very light. What BA can do now, others will do at a lower price in the coming years. The outlook for future lower cost light camping gear is good

  7. Wish they made a 10 x 10.

  8. Thanks Walter. I almost always rig a tarp in the diamond configuration. 8.5 x 8.5 is just a little too small to handle rain coming down sideways.

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