Where the result comes from
You put in€108,000Historical growth€631,891
Returns, in plain English.
A historical S&P 500 investment calculator
Plan an investment. See what the numbers mean.
Choose what the money should do. We replay your plan through 98 years of S&P 500 total return history, including dividends.
1
What are you planning for?
Choose the answer you want.
EUR
years
Fine-tune assumptions2.5% inflation
Annual contribution increase
The monthly contribution rises every 12 months, and the percentage is applied again each following year.
At 3%, €300 becomes €309 next year: +€9 per month.
Why inflation matters
Inflation translates a future amount into today's buying power. A higher assumption does not change the portfolio balance, but it lowers what that future money may buy.
The 2.5% default is a long-term planning assumption, not a prediction for next year.
% / yearPossible value in 2056
€352,738in today's buying powerCalculated across69 complete historical periods
TodayThree data-based scenarios30 years
- Money contributedMoney contributed
Your portfolio's value today plus all future contributions in the plan. It does not include the investment growth added by the model.
- €108,000
- Estimated end valueEstimated end value
The nominal portfolio balance at the end of the plan under the selected historical scenario. It is expressed in money from that future year.
- €739,891
- In today’s moneyIn today’s money
The estimated end value after adjusting for your inflation assumption, so it can be compared with prices and purchasing power today.
- €352,738
- Equivalent annual returnEquivalent annual return
A single constant annual rate that would reproduce the same ending value with the same contribution schedule. It explains the result; it is not a guaranteed future return.
- 10.9%
Which history should the plan face?
Compared across 69 complete periods. Typical is the historical median; the other two are deliberately lower.
Typical history: The median result across every complete historical period available.
What changes the result most?
- Invest €10 more monthly
- +€11,758
- Keep investing 5 extra years
- +€162,660
- Wait 5 years, keep the same end date
- −€128,713
How it works
Start with the plan you know.
You do not need to choose an expected return. Tell us what you can invest and what you want the money to do.
Build your plan
Set a monthly amount and a time period. Add an existing portfolio, a break, or another contribution phase only if you need it.
Run it through history
We apply the same plan to every complete period available in the S&P 500 total return record from 1928 to 2025.
Read the answer
See the estimated result, its value in today's money, and how much came from your contributions. Switch scenarios when you want a more cautious view.
Methodology
What sits behind the result.
Plain Returns keeps the calculation out of the way, but it does not hide how the answer was made.
Historical data
We use annual S&P 500 total returns, including dividends, from 1928 to 2025. The dataset is published by Aswath Damodaran at NYU Stern.
Testing your plan
Your contribution schedule is replayed across every complete historical window that matches its length. The ending balances are sorted before a scenario is selected.
The three scenarios
Typical history uses the 50th percentile result. Cautious history uses the 35th percentile. Difficult history uses the 10th percentile. These are positions in the historical results, not return rates chosen by us.
Monthly contributions
Each annual market return is converted to an equivalent monthly rate. Contributions are added monthly and follow the life phases in your plan. Any break in contributions must be added by you.
Today's money
The future balance is divided by your inflation assumption for the full length of the plan. This gives a rough comparison with purchasing power today.
Monthly income
The growth option converts the selected equivalent annual return into a monthly estimate while the portfolio stays invested. The spenddown option calculates a level payment intended to use the portfolio over the chosen number of years.
The equivalent annual return is the constant rate that would recreate the selected ending balance with the same contributions. It is there to explain the result, not predict the future. Broker commissions, fund costs, taxes and currency movements are not included. Plain Returns is an educational planning tool and does not provide investment advice.