The USDA nutrient database lists cider vinegar as 33.6 calories and 14.1g carb for 1 cup. That doesn't add up (4 calories per g?) so I'm guessing a % of the carbs are in the form of acetic acid. 33 calories would be 8.3g digestible carbs per cup, or 0.5g per Tbsp.

Corrine T. Netzer lists 2 calories and 0.5g carbs per Tbsp of cider and wine vinegar, and 0 cals/0 carbs for plain distilled white vinegar.

Balsamic vinegar is indeed higher carbs ... 2g per Tbsp. A little goes a long way though, so 1 Tbsp in a whole recipe might not break the carb budget.

hth,

Doreen