Asset allocation is the single biggest decision that drives your long-term investment returns. Research from Vanguard and Brinson, Hood, and Beebower has repeatedly shown that roughly 90% of a portfolio's risk and return comes from how you split money across stocks, bonds, and cash — not from which individual funds you pick or when you trade them.
This calculator starts with the classic "120 minus your age" rule of thumb, adjusts that starting point up or down for your risk tolerance, and then tells you exactly how many dollars to hold in U.S. stocks, international stocks, bonds, and cash. It also gives you a simple rebalancing band so you know when to trim winners and refill laggards. Adjust the inputs and every figure updates instantly.
How to Use
- Enter your Age. The modern rule of thumb sets your stock share at roughly 120 minus your age. A 35-year-old starts near 85% in stocks; a 65-year-old starts closer to 55%.
- Enter your Total Portfolio — the dollar amount you have invested today or plan to move into this allocation. The calculator multiplies each target percentage by this total to give you real dollar figures.
- Choose your Risk Tolerance. Conservative tilts the mix toward bonds and cash; aggressive tilts it toward stocks; moderate uses the raw 120-minus-age number.
- Read the recommended Stock / Bond / Cash percentages at the top of the result card.
- Look at the dollar split across U.S. stocks, international stocks, bonds, and cash. Within the stock portion, this tool keeps 60% in U.S. markets and 40% in international markets — a common neutral starting point.
- Note the rebalancing band of plus or minus 5 percentage points. When any fund drifts more than that from its target, sell the overweight piece and buy the underweight one to bring the portfolio back to plan.
The 120-Minus-Age Rule
The traditional rule was "100 minus your age." Because life expectancy has risen and retirement now often lasts 25 to 30 years, many advisors now use 120 minus your age as a more growth-oriented starting point.
The formula is deliberately simple:
- Stock share = 120 − age (clamped between 0% and 100%).
- The remainder is split between bonds and cash.
At age 35, that is 120 − 35 = 85% stocks and 15% for bonds plus cash. At age 60, it is 120 − 60 = 60% stocks and 40% bonds/cash. At age 80, it drops to 40% stocks, with the large remainder parked in safer fixed income. The logic is behavioral: younger investors have decades to recover from a bear market, while those near or in retirement cannot afford a deep crash right before they need to spend the money.
Conservative, Moderate, Aggressive
Your age gives a starting point, but your stomach for volatility matters too. This calculator applies a small risk overlay on top of the 120-minus-age number:
- Conservative shifts the stock share down by 20 percentage points and sets aside a 10% cash cushion. If the raw rule says 75% stocks, a conservative investor lands near 55% stocks, 35% bonds, and 10% cash.
- Moderate uses the raw 120-minus-age figure with a 5% cash buffer.
- Aggressive pushes the stock share up by 15 percentage points with no cash buffer, clamped so it never exceeds 100%.
Within the stock sleeve, U.S. stocks are kept at 60% and international stocks at 40%. This is a neutral, globally diversified split; you can tilt toward home-country bias or away from it based on your own conviction.
Examples
Example 1 — A 35-year-old professional. Age 35, $100,000 portfolio, moderate risk. The rule gives 120 − 35 = 85% stocks. The moderate overlay adds a 5% cash buffer, leaving 10% in bonds. Dollars: $51,000 in U.S. stocks, $34,000 in international stocks, $10,000 in bonds, and $5,000 in cash. If U.S. stocks rally and grow to $56,000 (a 6-point drift above target), the 5% rebalancing band triggers a trim.
Example 2 — A 50-year-old pre-retiree. Age 50, $250,000, conservative. Raw rule is 70% stocks; the conservative overlay subtracts 20 points to 50% stocks and holds 10% cash, leaving 40% bonds. Dollars: $75,000 U.S. stocks, $50,000 international stocks, $100,000 bonds, and $25,000 cash. The heavier bond and cash weight reduces the pain of a market drop in the decade before retirement.
Example 3 — A 28-year-old beginner. Age 28, $50,000, aggressive. Raw rule is 92% stocks; the aggressive overlay pushes it to 100% stocks (capped), with no bond or cash weight. Dollars: $30,000 U.S. stocks and $20,000 international stocks. This is the maximum-growth, maximum-volatility profile — appropriate only if you will not touch the money for 30+ years and can stomach 30–40% paper losses.
FAQ
What is the 120-minus-age rule?
It is a simple starting guideline: your percentage allocation to stocks should be about 120 minus your age. A 40-year-old, for example, lands near 80% stocks and 20% bonds and cash. It replaced the older "100 minus age" rule because longer lifespans and longer retirements demand more growth from equities.
Should I use 100, 110, or 120 minus my age?
Use 120 if you have a long horizon and tolerate volatility; use 100 if you are risk-averse or retired; 110 sits in the middle. The choice mainly moves your stock weight by 10–20 percentage points. This calculator uses 120 as its base and lets the risk-tolerance selector nudge it further.
How should I split stocks between U.S. and international?
A neutral starting point is 60% U.S. stocks and 40% international stocks, which is what this calculator uses. Many U.S. investors overweight domestic shares out of familiarity; global market cap weighting would actually put only about half in the U.S. Pick a split you can stick with through a full market cycle.
Why hold cash in a long-term portfolio?
A small cash buffer (this tool uses 5% for moderate, 10% for conservative) gives you dry powder to buy when markets drop and prevents you from selling bonds or stocks at a bad time to cover spending. It also reduces sequence-of-returns risk in retirement.
How often should I rebalance?
Rebalancing once or twice a year is usually enough, but a band rule is more disciplined: rebalance whenever any holding drifts more than 5 percentage points from its target. This calculator uses a 5% band. Rebalancing forces you to sell high and buy low automatically.
Is this allocation guaranteed to beat the market?
No. Asset allocation lowers risk and smooths returns; it does not guarantee gains or outperformance. Stocks can fall 30% or more, bonds can lose value when rates rise, and inflation erodes cash. Use this as a baseline and adjust for your own goals, tax situation, and time horizon.
Disclaimer
This asset allocation calculator is provided for informational purposes only and does not constitute financial, investment, tax, or legal advice. Allocations are based on the simplified 120-minus-age rule of thumb and the risk-tolerance overlay described above; they are not personalized recommendations. Investing involves risk, including the possible loss of principal, and past performance does not guarantee future results. Always consult a qualified financial advisor before making investment decisions.