Conservative4 % a year
€142,004
estimated net capitalCompound interest
Project contributions, inflation, tax and three return scenarios.
Interactive calculator
Build your scenario
Adjust the assumptions and compare future value before tax, after tax and in today's money.
Result after 20 years
€176,536
estimated net capital
- Gross final capital
- €195,082
- Total contributed
- €97,471
- Accumulated gain
- €97,611
- Estimated tax
- −€18,546
- Real purchasing power
- €118,804 net capital expressed in today's euros
Effective annual rate: 6.17%Contribution: end of month
Private calculation. Your figures are processed on this device and are not sent to a server.
Simulation, not a forecast. It assumes a constant return, constant inflation and one tax rate. It excludes fees, interim losses and regulatory changes and is not financial or tax advice.
Range of outcomes
Three scenarios, one strategy
We compare the base assumption with annual returns two percentage points lower and higher.
Base6 % a year
€176,536
estimated net capitalOptimistic8 % a year
€223,662
estimated net capitalAnnual evolution
How the capital grows
GrossNetContributed
| Year | Gross capital | Total contributed | Gain | Estimated tax | Net capital | Real value |
|---|---|---|---|---|---|---|
| Today | €10,000 | €10,000 | €0 | €0 | €10,000 | €10,000 |
| 1 | €14,317 | €13,600 | €717 | €136 | €14,181 | €13,903 |
| 2 | €18,975 | €17,272 | €1,703 | €324 | €18,652 | €17,927 |
| 3 | €23,996 | €21,017 | €2,978 | €566 | €23,430 | €22,078 |
| 4 | €29,403 | €24,838 | €4,565 | €867 | €28,536 | €26,362 |
| 5 | €35,222 | €28,735 | €6,488 | €1,233 | €33,989 | €30,785 |
| 6 | €41,480 | €32,709 | €8,771 | €1,667 | €39,814 | €35,354 |
| 7 | €48,206 | €36,763 | €11,443 | €2,174 | €46,032 | €40,074 |
| 8 | €55,431 | €40,899 | €14,532 | €2,761 | €52,669 | €44,953 |
| 9 | €63,185 | €45,117 | €18,069 | €3,433 | €59,752 | €49,998 |
| 10 | €71,505 | €49,419 | €22,086 | €4,196 | €67,309 | €55,217 |
| 11 | €80,426 | €53,807 | €26,619 | €5,058 | €75,369 | €60,616 |
| 12 | €89,988 | €58,284 | €31,705 | €6,024 | €83,964 | €66,205 |
| 13 | €100,232 | €62,849 | €37,383 | €7,103 | €93,129 | €71,992 |
| 14 | €111,201 | €67,506 | €43,695 | €8,302 | €102,899 | €77,985 |
| 15 | €122,943 | €72,256 | €50,686 | €9,630 | €113,312 | €84,193 |
| 16 | €135,506 | €77,101 | €58,405 | €11,097 | €124,409 | €90,625 |
| 17 | €148,944 | €82,043 | €66,901 | €12,711 | €136,233 | €97,293 |
| 18 | €163,313 | €87,084 | €76,228 | €14,483 | €148,829 | €104,204 |
| 19 | €178,671 | €92,226 | €86,445 | €16,425 | €162,246 | €111,371 |
| 20 | €195,082 | €97,471 | €97,611 | €18,546 | €176,536 | €118,804 |
Transparent methodology
What this does and does not calculate
The simulation compounds the selected return and adds contributions every month. Net value subtracts a single tax rate from positive gains as if the full investment were liquidated; real value discounts accumulated inflation.
Real outcomes may include volatility, fees, tax bands and changing inflation. Check any decision against official information and seek professional advice where appropriate.
Read the CNMV guide on inflation and savingDECISION GUIDES
P6Compound interest with monthly contributionsReproducible case and table→