Simple interest calculator
Simple interest is always calculated on the initial capital, without reinvesting the interest. It is the typical model of a fixed-term deposit.
Indicative calculation. The tax withholding is an advance payment; the final tax depends on the rest of your savings income. Not financial advice.
Capital growth
Show the chart data: Capital growth
Final value composition
- Capital€10,00063%
- Interest€6,00038%
Information, not tax or financial advice.
How the simple interest calculator works
Simple interest is always computed on the initial capital, without reinvesting what you earn. It's the opposite of compound: interest doesn't generate more interest.
How to read the result. The gross interest is capital × rate × years. The tax withholding (19 % by default in Spain, as on a fixed-term deposit) is applied to that interest: the net final value adds to the capital the interest after withholding.
Worked example (default values). €10,000 at 4 % for 15 years, with a 19 % withholding:
- Gross interest: €10,000 × 4 % × 15 = €6,000.
- Gross final value: €16,000.
- Withholding (19 %): €1,140 → net interest €4,860.
- Net final value: €14,860.
Compare it with compound interest on the same inputs: the gap widens the longer the term.
An important note. Simple interest appears in some short-term loans and in fixed-term deposits. The withholding is an advance payment, not the final tax, which depends on the rest of your savings income.