What are the best low-carb cocktail mixers?

Soda water (club soda) is the best at zero carbs and zero calories. Other keto-friendly mixers include diet tonic water, diet and zero-sugar sodas, sugar-free flavored seltzer, fresh citrus juice, sugar-free syrups, and sugar-free tonic or ginger beer. Avoid regular tonic, juice, soda, and sweet-and-sour mix.

Regular tonic water is not keto — it has about 32g of sugar per 12 oz, roughly the same as regular soda. Diet or sugar-free tonic water has close to zero carbs and is the keto-friendly swap.

What can I use instead of simple syrup on keto?

Use a sugar-free simple syrup, or make your own by dissolving monk fruit, allulose, or erythritol in warm water. These add sweetness with zero net carbs, unlike regular simple syrup (about 5g of sugar per teaspoon).

Is diet soda okay on keto?

Yes — diet and zero-sugar sodas (Diet Coke, Coke Zero, Sprite Zero) have zero carbs and work as keto mixers. Some people find artificial sweeteners affect appetite or cravings, so use what works for you.

What mixers should I avoid on keto?

Avoid regular tonic water, fruit juice, regular soda, energy drinks, sweet-and-sour mix, margarita mix, grenadine, and most flavored syrups — each can add 15–35g of sugar to a single drink.

Best Low-Carb Cocktail Mixers for Keto (Zero-Sugar)

The best low-carb and sugar-free cocktail mixers for keto — soda water, diet tonic, sugar-free syrups, and more. Plus the high-sugar mixers to avoid.

Priya Sharma

Nutrition Writer · July 14, 2026 · 2 min read

The carbs in almost any cocktail come from the mixer, not the alcohol — so the best low-carb mixers are soda water (0g), diet tonic, diet sodas, sugar-free seltzers, fresh citrus, and sugar-free syrups. Spirits are carb-free; the sugar hides in tonic, juice, and mix. Here's what to pour and what to skip.

Best low-carb cocktail mixers

Mixer	Net carbs (per serving)	Keto?
Soda water / club soda	0g	✅ Best
Diet tonic water	~0–1g	✅
Diet soda / Coke Zero / Sprite Zero	0g	✅
Sugar-free flavored seltzer	0g	✅
Fresh lime / lemon juice	~1g per wedge	✅
Sugar-free simple syrup	0g	✅
Sugar-free ginger beer	~1g	✅
Crystal Light / Mio drops	~0g	✅

The go-to: soda water

Club soda has zero carbs and zero calories, and it turns any spirit into a keto drink — a vodka soda, gin and soda, or tequila-lime-soda are all near 0g. Keep a bottle on hand and you can make a low-carb cocktail with almost anything.

Diet tonic instead of regular

A gin and tonic is a keto trap only because of the tonic: regular tonic water has about 32g of sugar per 12 oz. Swap in diet or sugar-free tonic and the same drink drops to about 1g.

Sugar-free syrups for flavor

To sweeten a cocktail without sugar, use a sugar-free simple syrup or make one from monk fruit, allulose, or erythritol dissolved in warm water. These sub 1:1 for simple syrup in a margarita, mojito, or old fashioned with zero net carbs.

The high-sugar mixers to avoid

These are where a "zero-carb" spirit becomes a sugar bomb:

Regular tonic water — ~32g per 12 oz (as much as soda)
Fruit juice — orange, cranberry, pineapple: 20–30g+
Regular soda — Coke, Sprite, ginger ale: ~27–39g
Sweet-and-sour / margarita mix — 20–30g
Energy drinks (regular) — ~27g
Grenadine, simple syrup, flavored syrups — 5g+ per pump

Build any keto cocktail

Once you swap the mixer, almost any drink works: spirit + soda water + citrus, or spirit + diet soda. See the full playbook in keto cocktails, plus carbs in vodka, carbs in whiskey, and the keto margarita recipe.

The easiest way to keep drinks keto is to track them — CarbMeNot shows the net carbs for mixers, spirits, and cocktails and logs them from a photo, free on iOS and Android. Check any mixer with the free Is It Keto? tool.

Frequently asked questions

What are the best low-carb cocktail mixers?: Soda water (club soda) is the best at zero carbs and zero calories. Other keto-friendly mixers include diet tonic water, diet and zero-sugar sodas, sugar-free flavored seltzer, fresh citrus juice, sugar-free syrups, and sugar-free tonic or ginger beer. Avoid regular tonic, juice, soda, and sweet-and-sour mix.
Is tonic water keto?: Regular tonic water is not keto — it has about 32g of sugar per 12 oz, roughly the same as regular soda. Diet or sugar-free tonic water has close to zero carbs and is the keto-friendly swap.
What can I use instead of simple syrup on keto?: Use a sugar-free simple syrup, or make your own by dissolving monk fruit, allulose, or erythritol in warm water. These add sweetness with zero net carbs, unlike regular simple syrup (about 5g of sugar per teaspoon).
Is diet soda okay on keto?: Yes — diet and zero-sugar sodas (Diet Coke, Coke Zero, Sprite Zero) have zero carbs and work as keto mixers. Some people find artificial sweeteners affect appetite or cravings, so use what works for you.
What mixers should I avoid on keto?: Avoid regular tonic water, fruit juice, regular soda, energy drinks, sweet-and-sour mix, margarita mix, grenadine, and most flavored syrups — each can add 15–35g of sugar to a single drink.