Comprehensive Guide
Learn more in our Investing Guide.
How it works
asset allocation by age calculator takes your inputs and produces recommended stock %, recommended bond %, international (of stock allocation), suggested fund types. Determine the right stock/bond allocation based on your age, goals, and risk tolerance using proven formulas. You provide 3 inputs: Your age (number) (default: 35); Risk tolerance (conservative/moderate/aggressive) — choose from Conservative, Moderate, Aggressive (default: "moderate"); Portfolio size (currency, in dollars) (default: 100000 dollars). The calculator returns 4 outputs: Recommended stock % (the primary result); Recommended bond % (a secondary output); International (of stock allocation) (a secondary output); Suggested fund types (a supplementary figure). Investment calculations rest on a few variables — principal, return rate, time, and compounding — but their interaction is non-linear enough that intuition alone gets the answer wrong more often than not. This tool runs the real formula with your inputs and shows the numbers that matter, not the rounded approximations from a textbook. The underlying formula: Stock % = (100 or 110) − Age, adjusted for risk tolerance | Bonds % = 100 − Stock % With the default values, recommended stock % is computed from the interaction of every input field — change any one of them and the result updates immediately, so you can stress-test different scenarios without re-entering the whole form. Adjust the inputs to match your real financial situation. The defaults are realistic starting points, but every person's circumstances differ — your actual income, expenses, rates, and timelines will produce a different answer. Use the tool iteratively: start with the defaults, then change one variable at a time to see which factor has the largest impact on your outcome.Formula
Stock % = (100 or 110) − Age, adjusted for risk tolerance | Bonds % = 100 − Stock %
Tips
- The Rule of 110 is more appropriate for modern longer lifespans than the Rule of 100.
- A 60/40 stock/bond portfolio has historically returned 8–9% annually.
- Rebalance annually to maintain your target allocation.
- Simple is better: a 3-fund portfolio covers all asset classes.
Frequently asked questions
What is the right stock allocation for my age?
Rule of thumb: 110 − your age = stock percentage. At 35: 75% stocks, 25% bonds. At 55: 55% stocks, 45% bonds. Adjust ±10% based on risk tolerance.
Should I follow the 100 or 110 rule?
The 110 rule is better for most people. Longer lifespans and lower bond yields mean you need more growth (stocks) to fund a longer retirement. Conservative investors can use 100 or even 90.
How accurate are the calculator results?
The math is exact — the same formulas a financial professional would use by hand. The precision of the output depends entirely on how realistic your inputs are. Use your actual numbers rather than estimates when possible. The defaults are reasonable starting points, but your real income, rates, and timeline will produce a different result.