Why compare scenarios?
Compound interest is very sensitive to the interest rate: a couple of percentage points seem small each month, but over 20 or 30 years they completely change the result. That's why, instead of giving a single number, you can see three "blueprint revisions" at once: a conservative, a moderate, and an aggressive scenario, with the same contribution.
Fact: going from 4% to 7% interest doesn't just double the 20-year result — it can triple it, depending on the term and contribution.
Goal mode: the reverse of the usual approach
Most calculators only answer "how much will I have". Goal mode answers the opposite question, which is what people actually use when planning: "I want to have €50,000 in 15 years, how much do I need to set aside each month?". It's the same compound interest formula, solved for the contribution instead of the final capital.
Year-by-year table (moderate scenario)
| Year | Contributed | Interest | Total |
|---|