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.

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.

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.

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.

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.

In retirement, most guidance shifts toward capital preservation over growth, since you're withdrawing rather than contributing and have less time to recover from a downturn. Many retirees hold more bonds and cash than they did while working — the "110 minus age" rule of thumb would put a 70-year-old around 40% stocks — but holding too little in stocks risks running out of money over a 20-30 year retirement, since inflation still erodes cash and bonds. Model your own tradeoff by testing a more conservative mix (a heavier bond and cash weighting) above, and pair it with the withdrawal calculator to see how your allocation affects how long your savings last.

A widely cited benchmark from Fidelity Investments suggests saving 15% of your gross income each year toward retirement, including any employer match, starting around age 25 to stay on track for a retirement around age 67. That 15% figure is a starting target, not a hard rule for every situation. If your employer offers a 401(k) match, contribute enough to capture the full match first, before working toward 15% overall, since that match is money you'd otherwise leave on the table. Someone starting later than 25, carrying high-interest debt, or working without an employer match may need a different number. Once you land on a percentage that fits your own budget, the calculator above shows what that monthly contribution grows into over time.

As a general guideline (not personalized advice), allocation typically shifts toward more bonds and less stock risk with each decade: someone in their 30s might lean heavily toward stocks for maximum growth time, someone in their 40s-50s might start trimming stock exposure and adding bonds as retirement comes into view, and someone in their 60s often shifts further toward bonds and cash to protect savings close to or during retirement. The "110 minus your age" rule approximates this glide path, but your own time horizon, other income sources, and risk tolerance should drive the actual split — test different ages' typical mixes in the calculator above.

Asset allocation and diversification work together, but they answer different questions. Asset allocation sets how much of your money sits in each broad asset class: stocks, bonds, real estate, and cash, the same four this calculator uses. Diversification is spreading money within and across those classes so no single company, sector, or bond issuer can sink your results by itself. A portfolio can have the right allocation and still be poorly diversified. 60% in stocks split across three individual companies is one example, versus that same 60% in a broad index fund holding hundreds. Get the allocation right first, then diversify within each slice with a broad fund instead of a handful of individual picks.

Either approach works, and the choice comes down to control versus automation. Building your own mix, like the calculator above, lets you set an exact stock-bond-cash split and change it whenever your goals shift. A target-date fund automates the same idea, shifting from stocks toward bonds on its own as the target year approaches. That automation carries a fund-level expense ratio you skip when you build the mix yourself with separate index funds. Pick a target-date fund if you would rather hold one line and skip the yearly rebalancing check-in. Use this calculator instead if you want a specific split, like 70/30, or an age-based mix that doesn't match a standard target-date year. See target-date fund vs. S&P 500 for how a target-date fund's own stock exposure compares to an all-stock benchmark.