How they differ
Under the hood, ABV Calculator (Brewing) uses standard brewing formulas (tinseth, daniels) fed by volume, gravity, hop bill, fermentation profile. Carbonation Calculator (Brewing) uses standard brewing formulas (tinseth, daniels) fed by volume, gravity, hop bill, fermentation profile. The two are not substitutes; they answer adjacent questions in your workflow.
Pick ABV Calculator (Brewing) when your question is about abv calculator (brewing) and your inputs are volume, gravity, hop bill, fermentation profile. Pick Carbonation Calculator (Brewing) when the question shifts to carbonation calculator (brewing) and your inputs become volume, gravity, hop bill, fermentation profile. If neither matches what you need, the Brewing category hub lists every tool we have for related questions.