Asset Allocation Calculator
The asset allocation calculator above shows how to split your money across stocks, bonds, real estate, and cash. Enter your balances and time horizon to see your portfolio's expected return, volatility, and long-run growth.
Your mix of asset classes drives most of your return swings over time, often more than which individual stocks you pick. This tool helps you find a blend that fits your goals and your tolerance for risk.
How it's calculated
The asset allocation calculator weighs each asset class by the dollars you assign to it. Each class carries a long-run return and volatility estimate: stocks 10% return at 16% volatility, bonds 4% at 5%, real estate 8% at 15%, and cash 2.5% at 1%. These are model assumptions, not guarantees, and real results will vary year to year.
The tool then combines those weights into one expected return and one portfolio volatility. Because assets that do not move together offset each other, your blended risk lands below the simple average of the parts. The calculator also reports a Sharpe ratio, which measures return earned per unit of risk above a 2.5% risk-free rate. To compare risk-adjusted mixes, see the portfolio risk calculator.
A worked example
Imagine a $100,000 portfolio split as $50,000 stocks, $20,000 bonds, $20,000 real estate, and $10,000 cash. That is a 50% / 20% / 20% / 10% mix.
Under the model, it carries a 7.65% expected return and 10.28% volatility, for a Sharpe ratio of 0.50. Adding $500 every month for 25 years, the calculator projects the portfolio growing to about $1,048,304.
Common mistakes to avoid
- Treating the model returns as guarantees. The 10% stock and 4% bond figures are long-run estimates, and any single year can look very different.
- Holding too much cash for a long horizon. Cash earns about 2.5% in the model, so it can lag inflation over decades.
- Chasing individual stock picks instead of setting the asset mix first. Allocation drives most of your return variability.
- Never rebalancing. When stocks surge, your mix drifts toward more risk than you chose, so periodic rebalancing matters.
- Ignoring your time horizon and risk tolerance, the two factors the SEC says should shape your allocation.
Frequently asked questions
What is an asset allocation calculator?
An asset allocation calculator shows how to divide your portfolio across stocks, bonds, real estate, and cash. It estimates your blended expected return, your overall risk, and how the portfolio could grow over time. You enter your balances and contributions, and the tool does the math.
How should I split stocks, bonds, real estate, and cash?
Base your split on your time horizon and your tolerance for risk, the two factors the SEC highlights. Longer horizons can support more stocks; shorter horizons lean toward bonds and cash. The calculator above lets you test different mixes and compare the results.
What is the "110 minus your age" rule?
A common rule of thumb is to hold roughly 110 minus your age in stocks. A 40-year-old would target about 70% stocks. This is only a guideline, not a personalized plan, so adjust it for your own goals and comfort with risk.
Does diversification really lower risk?
Yes. Spreading money across assets that do not move together reduces overall volatility. In the worked example, a diversified mix shows 10.28% volatility, well below the 16% of stocks alone. Diversification cannot remove all risk, but it cushions losses in any single asset.
What is rebalancing and why does it matter?
Rebalancing means resetting your portfolio back to its target mix after market moves. When one asset class grows, it can crowd out the others and raise your risk. Rebalancing forces you to buy low and sell high, and the SEC suggests reviewing your mix periodically.