How they differ
Under the hood, Abgeltungssteuer Calculator uses compound arithmetic with cash flow timing fed by income, expenses, balances, rates. Brutto-Netto Rechner uses lohnsteuer + sv-beiträge per steuerklasse fed by brutto salary, tax class, land, church tax, kids. The two are not substitutes; they answer adjacent questions in your workflow.
Pick Abgeltungssteuer Calculator when your question is about abgeltungssteuer and your inputs are income, expenses, balances, rates. Pick Brutto-Netto Rechner when the question shifts to brutto-netto rechner and your inputs become brutto salary, tax class, land, church tax, kids. If neither matches what you need, the Personal Finance category hub lists every tool we have for related questions.