Portfolio Growth Projector
More stocks raises your expected outcome, but also the depth of the hole you may have to climb out of. Compare two allocations and see, in dollars, what you would gain and what you would have to endure with each.
How much would each one have?
The same money and the same horizon, with two different allocations.
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How does it grow?
Both paths against the money you put in yourself.
How much would the worst day hurt?
A disaster dress rehearsal: the stock market crashes 50%, something that has happened several times in a century.
| Portfolio | If stocks fall 50% | In dollars, at the end of the plan | If bonds also fall 10% |
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Falling is half the story; getting back is the other half
- 100/0−50%Has spent more than a decade underwater (2000-2013).
- 50/50−25%Around half that time.
- Conservative−12.5%A couple of years (25/75).
Recovery times are rough guides: they depend on the period, the market, the currency and rebalancing. Investors who kept contributing every month recovered much sooner, because they were buying cheap the whole way through.
What if you start out unlucky?
Same returns afterwards, different order of years: sequence-of-returns risk.
Turn on the bad sequence to see what it would cost if stocks fell −20% and −10% right in the first two years.
| Portfolio | No shocks | Bad sequence | What it costs |
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After the two bad years, the model goes back to each portfolio's average return. The portfolio with more bonds cushions the blow. It hurts most once you start living off the portfolio, which is why a cash reserve and gradually turning the dial towards safety matter near retirement.
Deterministic model with fixed assumptions: stocks return 7% a year and bonds 3% a year (nominal long-term averages, before fees and taxes). The worst day follows simple arithmetic: a 50% stock market crash pulls each portfolio down in proportion to its stocks; the right-hand column adds a 10% fall in bonds, like in 2022. It doesn't use live historical data or predict the future. The risk that actually matters isn't the one a chart measures, but the one that would make you abandon your plan.
What each figure means
A quick look at every input and every result.
The starting capital and what you add each month — the same for both portfolios, so the only difference between A and B is the allocation.
The percentage in stocks for each portfolio; the rest goes to bonds. It's the one decision that actually matters: you can't edit the expected return of each asset, only how much you put into each one.
Adds two down years at the start of the horizon. With the same final allocation, a bad start changes the outcome a lot — that's sequence-of-returns risk.
The outcome of allocation A at the end of the chosen horizon.
The outcome of allocation B, with the same capital and horizon.
The initial investment plus every monthly contribution over the horizon. Everything above it came from the market.
What each portfolio would lose if stocks crashed 50%, as a percentage and in dollars on the final value. It isn't a forecast: it's the rehearsal that tells you whether you'd hold on without selling.
How to fill in this calculator
- Initial and monthly contribution: the same starting capital and the same monthly saving for both portfolios — so the only difference between A and B is the allocation, not the money you put in.
- Time horizon: how many years you keep the plan going. With short horizons the allocation matters less; over 20-30 years, the gap between 80/20 and 40/60 is much more noticeable.
- Portfolio A — Equities: the allocation you want to test. Use the shortcuts (100/0, 80/20, 60/40, 40/60) or the slider; the rest goes to bonds.
- Portfolio B — Equities: the comparison allocation. There is no "correct" one: the point is to see the same capital under two different decisions.
- Read the results in order: first how much each portfolio would have, then how it grows, and finally how much it would lose on the worst day. Together, those three are the decision: not just how much each allocation returns, but how much it hurts when the market falls.
- Picture the worst: look at the dollar figure of the fall and ask yourself whether you'd keep contributing every month without selling. If you hesitate, go with the more cautious allocation.
- Simulate a bad sequence: two losing years (−20% and −10%) at the start of the horizon. With the same returns afterwards, a bad start changes the outcome: that's sequence-of-returns risk.
Frequently asked questions about this calculator
Why can't I change the expected return on stocks and bonds?
That's deliberate: if you could pick optimistic returns, any allocation would look good. By fixing them (7% and 3% long-term averages), the simulator isolates the one variable that actually decides the outcome — the split between the two.
What is "sequence risk" and why does it matter so much early on?
A downturn early in the horizon hits the money that will stay invested the longest, and what is lost that year no longer compounds for the rest of the plan. It hurts most when you start living off the portfolio, because there are no contributions left buying cheap.
Where does the worst-day fall come from?
From a disaster dress rehearsal: assume stocks fall 50%, which has happened several times in a century. The arithmetic is linear: a 100/0 portfolio falls 50%, an 80/20 falls 40% and a 50/50 falls 25%. Since bonds also fell in 2022, the last column adds a 10% fall in bonds: a real crisis will probably land somewhere between the two.
Does this include taxes?
No. This calculator compares allocations while the money stays invested. Taxes apply when you withdraw — that's a separate topic this tool doesn't cover.