Asset Allocation by Age Calculator

How it is calculated

The stock share is a fixed number minus your age, limited to the range 0 to 100: stocks % = rule − age, bonds % = 100 − stocks %. The rule must be 100, 110 or 120, with 110 used when the field is left empty; any other value, such as 105, gives no result. A higher number keeps more in stocks at any age. Then stocks value = portfolio_value × stocks % ÷ 100 and bonds value = portfolio_value × bonds % ÷ 100. If age is at or above the rule number, stocks are set to 0% and everything is shown as bonds; if the rule minus age exceeds 100, stocks are capped at 100%. Age must be between 0 and 130 and the portfolio value cannot be negative, otherwise there is no result. The percentage line is rounded to a whole number, while the money amounts use the exact figure. This is a simplified guideline: it ignores risk tolerance, goals, taxes and other assets.

Common mistakes

• Treating the output as personal advice. The rule uses only your age, so two people with the same age but different goals or risk tolerance get the same answer.
• Mixing up the rule number with a target age. The rule (100, 110 or 120) is the number your age is subtracted from, not a retirement age; typing a custom number like 105 gives no result.
• Entering years to retirement instead of current age. The formula expects your age today.
• Entering the portfolio value as a monthly contribution. The split applies to the total balance you want to allocate.
• Forgetting that the rule changes the answer by a lot. At 35, the 100 rule gives 65% stocks and the 120 rule gives 85%, so choose one deliberately.