Interest & Compound Interest Calculator 2026 — Free Online
Calculate compound interest with the Rule of 72: capital doubles in 14 years at 5% p.a. Add monthly savings, get full amortization. Free, no registration.
Final capital
16.288,95 €
Total deposits
10.000,00 €
Interest earned
6.288,95 €
| Year | Balance | Deposits | Interest |
|---|---|---|---|
| 1 | 10.500,00 € | 10.000,00 € | 500,00 € |
| 2 | 11.025,00 € | 10.000,00 € | 1.025,00 € |
| 3 | 11.576,25 € | 10.000,00 € | 1.576,25 € |
| 4 | 12.155,06 € | 10.000,00 € | 2.155,06 € |
| 5 | 12.762,82 € | 10.000,00 € | 2.762,82 € |
| 6 | 13.400,96 € | 10.000,00 € | 3.400,96 € |
| 7 | 14.071,00 € | 10.000,00 € | 4.071,00 € |
| 8 | 14.774,55 € | 10.000,00 € | 4.774,55 € |
| 9 | 15.513,28 € | 10.000,00 € | 5.513,28 € |
| 10 | 16.288,95 € | 10.000,00 € | 6.288,95 € |
Note: These calculations are for informational purposes only and do not replace professional tax or financial advice. All information without guarantee.
Frequently Asked Questions
What is the compound interest effect?
With compound interest, returns are reinvested and earn interest themselves. Capital grows exponentially. At 5 % p.a. money doubles in approx. 14.4 years (Rule of 72: 72 ÷ rate).
What are good savings rates in Germany in 2026?
In 2026 German banks offer approx. 2.5–3.5 % p.a. for overnight money. Fixed deposits (1 year) yield approx. 3.0–3.8 %. Comparing offers is worthwhile as rates vary widely.
How do I calculate the real interest rate?
Real rate ≈ nominal rate − inflation rate. At 3 % nominal and 2.3 % inflation the real rate is only approx. 0.7 %. That is the actual purchasing power gain of your savings.
What does p.a. mean?
"p.a." stands for "per annum" (Latin: per year). A rate of 4 % p.a. means 4 % interest per year. Monthly: 4 % ÷ 12 ≈ 0.333 % per month.
What is the Interest & Compound Interest Calculator 2026 — Free Online?
The interest calculator computes interest, compound interest and final capital for savings and investments. It supports simple and compound interest as well as regular contributions.
How does the Interest & Compound Interest Calculator 2026 — Free Online work?
Enter starting capital, interest rate, term and optional monthly savings. Simple interest: interest = capital × rate × years. Compound interest: final capital = capital × (1 + rate)^years. With monthly contributions the geometric series is used.
Key Data and Facts
Compound interest: at 5 % p.a. capital doubles in approx. 14.4 years (Rule of 72: 72 ÷ rate). Overnight money Germany 2026: approx. 2.5–3.5 % p.a. Fixed deposit 1 year: approx. 3.0–3.8 % p.a. Inflation 2026: approx. 2.3 %. Real return = nominal rate minus inflation.
Step-by-Step Guide
Step-by-step: 1. Enter capital and rate. 2. Choose interest type: simple or compound. 3. Set term in years. 4. Optional monthly savings. 5. Read final capital. 6. Rule of 72: years to double = 72 ÷ rate (%)
Calculation Example
5,000 EUR, 3 % p.a., 10 years compound: final capital 6,720 EUR, interest 1,720 EUR. With 100 EUR/month savings: final capital 20,820 EUR.
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