Kirkland Signature Protein Bar Nutrition Facts: 21g Protein, 190 Calories — and Half the Price of Quest

Kirkland Signature Protein Bar: Nutrition Facts

All figures below are per single 60g bar and are consistent across our own previously published coverage of this product.

The sweetener system is erythritol and stevia — the same low-glycemic combination used in Quest bars, and a meaningfully gentler choice on the gut than the maltitol used in bars like Barebells or Grenade Carb Killa. The 12g of fiber per bar is the standout number here: it’s well above most mainstream bars and is a major reason this bar is filling relative to its 190 calories.

Kirkland vs. Quest: Nearly Identical Macros, Very Different Price

The headline story with this bar isn’t its nutrition — it’s that the nutrition is essentially a copy of the category leader at a fraction of the cost.

Calories, protein, fiber, sugar, and sweetener system are, by the numbers, the same bar. The difference is distribution: Quest is sold everywhere from gas stations to Target at a premium for that convenience, while Kirkland Signature is a Costco-only bulk product. For the full Quest breakdown, see our Quest protein nutrition guide.

The Real Cost Per Gram of Protein

Using the formula from our cost-per-gram of protein guide — price per serving divided by grams of protein — the math on this bar is straightforward:

$1.25 ÷ 21g protein = $0.0595, or roughly $0.06 per gram of protein.

A single Quest bar bought at retail (~$2.50) works out to $0.119 per gram — almost exactly double. Even Quest bought in its own 16-pack bulk format (~$2.25/bar) still runs $0.107 per gram, nearly double Kirkland’s per-gram cost. Put in monthly-budget terms: a $50 budget buys about 40 Kirkland bars for 840g of total protein, versus roughly 18 Quest bars for 378g of protein at retail bulk pricing — more than double the protein for the same spend, with an identical macro profile per bar.

The Trade-Offs: What You Give Up for the Price

• Costco membership required. This bar isn’t available to non-members, so the low per-bar price only pencils out if you already shop at Costco or are willing to pay for a membership.
• Narrower flavor range. Quest and ONE Bar both offer a wider flavor rotation. If flavor variety matters to you week over week, this is the category’s weak point.
• Bulk-box commitment. Costco sells this bar in large multi-packs, not single units, so you’re committing to a full box rather than trying one bar first.
• Fewer grab-and-go locations. Quest’s biggest practical advantage is that it’s sold virtually everywhere — gas stations, vending machines, convenience stores — for the moments you didn’t plan ahead. Kirkland Signature only comes from a Costco run.

Who This Bar Is For

If you already have a Costco membership and go through protein bars regularly — stocking a home gym, an office drawer, or a family that snacks on them daily — this is close to the best per-dollar protein bar available, without sacrificing the fiber, low sugar, or gentler sweetener profile that makes Quest the category benchmark. It is not the right pick if you need single-bar flexibility, wide flavor variety, or grab-and-go access outside of a Costco trip. For more bulk Costco protein picks, see our best protein snacks at Costco guide.

Frequently Asked Questions

Is the Kirkland Signature Protein Bar the same as a Quest bar?

The nutrition panel matches almost exactly — 21g protein, 190 calories, 12g fiber, 1g sugar, and the same erythritol-and-stevia sweetener system. The two are not confirmed to be made in the same facility, but on the numbers alone, Kirkland Signature delivers the same macro profile as Quest at roughly half the cost per gram of protein.

How much protein is in a Kirkland Signature Protein Bar?

21g of protein per 60g bar, at 190 calories, 1g of sugar, and 12g of fiber.

Where can I buy Kirkland Signature Protein Bars?

Exclusively at Costco, sold in bulk multi-packs, and requires an active Costco membership.

Is the Kirkland Signature Protein Bar good for weight loss?

Its combination of 21g of protein and 12g of fiber for 190 calories is a strong profile for satiety on a calorie budget — comparable to Quest, which is one of the more filling mainstream bars on the market thanks to its fiber content. See our best high-protein snacks for weight loss guide for more options.

What sweetener does the Kirkland Signature Protein Bar use?

Erythritol and stevia — a near-zero glycemic-index combination that tends to cause fewer GI issues than the maltitol used in bars like Barebells or Grenade Carb Killa.

Bottom line: the Kirkland Signature Protein Bar is, by the numbers, a near-identical twin of the Quest Protein Bar — 21g protein, 190 calories, 12g fiber, 1g sugar, the same erythritol-and-stevia sweetener — sold at roughly half the cost per gram of protein. The catch is access: it’s a Costco-only, bulk-box product with a narrower flavor range than Quest or ONE Bar, so it rewards people who already shop there regularly rather than those who need single-bar, grab-and-go flexibility. For households that go through protein bars often, it’s one of the strongest value picks in the category. Compare it against the rest of the field in our best protein bars of 2026 guide, the cost-per-gram of protein guide, and the full protein snacks directory.