Free asset allocation calculator
An asset allocation calculator shows how your stock/bond mix changes the range of outcomes — not just the average. More stocks lift the median result but widen the swings; more bonds steady the ride but can fail to outpace inflation over a long retirement. Coastline runs your allocation through real market history so you see the honest trade-off, not a single projected line.
Outcomes by stock/bond mix
Ending balance (today's dollars) across 700 historical-market simulations for a retiree at 65. The 10th percentile is the "bad luck" case; the 90th is "good luck":
| Allocation | Downside (10th %ile) | Median | Upside (90th %ile) |
|---|---|---|---|
| 20% / 80% | $128,256 | $411,589 | $2,734,489 |
| 40% / 60% | $353,130 | $1,041,265 | $3,572,446 |
| 60% / 40% | $572,044 | $1,885,031 | $4,548,079 |
| 80% / 20% | $824,337 | $2,890,581 | $5,820,101 |
| 100% / 0% | $1,016,313 | $4,407,211 | $8,847,398 |
How to choose your allocation
- Long horizon favors stocks. Over 20–30+ years inflation is a bigger threat than volatility, so too few stocks can quietly fail to keep up.
- Sequence risk favors some bonds near retirement. A bond/cash buffer lets you avoid selling stocks into an early downturn — the most dangerous moment for a portfolio.
- Match it to your income floor. If guaranteed income (Social Security, a pension) covers essentials, you can hold more stocks with the rest.
- Rules of thumb are a starting line. "110 minus your age in stocks" anchors you to a sensible neighborhood, but it can't see your horizon, income, or nerves.
Why Coastline's version is different
Most free calculators hand you a single headline number with the assumptions hidden. Coastline is built the opposite way:
- Real tax math, not a flat rate. It applies federal and state income tax, long-term capital-gains rules, and account-by-account treatment (taxable, traditional, Roth) — in both your working years and retirement.
- The whole journey. It models accumulation (saving and investing) and drawdown (spending it down), so you see how the plan connects end to end, not just one half.
- The math is shown. Every figure has a click-through breakdown of how it was computed — a level of transparency even paid tools rarely expose.
- US and Canada. It natively handles Canadian plans (RRSP, TFSA, CPP, OAS) alongside US accounts, which most calculators ignore.
- Free, no signup. No account, no email, no account-linking. Your inputs run the projection and are then discarded.
These figures assume a retiree at 65 with modest Social Security drawing $45,000/yr; historical-cycle simulation, deflated to today's dollars. Your horizon and income change the right mix — test yours in the calculator's Simulation Tools.
Common questions
What does an asset allocation calculator do?
It shows how your split between stocks and bonds affects the range of outcomes — the downside, median, and upside — rather than a single projected number. That range is the real trade-off between growth and stability.
What is the best stock/bond allocation?
There isn’t one "best" — it’s a trade-off. More stocks raise the median but widen the range; a middle mix (often 50–70% stocks) balances growth against stability. The right choice depends on your horizon, other income, and risk tolerance.
How much should I have in stocks by age?
A common rule of thumb is "110 minus your age" in stocks, but treat it as a starting point. Over a long horizon, holding enough stocks to outpace inflation can matter as much as limiting volatility.
Is the calculator free?
Yes, completely free with no signup, and it runs your allocation through real historical market sequences with full tax math.