The asset allocation calculator suggests a stock, bond, and cash mix from your age and risk tolerance, anchored to the rule of 110 and 2026 expected returns. Allocation drives roughly 90 percent of portfolio variance over time (Brinson, Hood, Beebower 1986).
Suggested stock / bond / cash split based on age and risk tolerance.
Starts from the classic "120 minus age" stock target then adjusts by risk tolerance and reserves cash. Conservative = 80% of baseline stocks. Aggressive = 110% (clamped at 100%).
An asset allocation calculator is a portfolio design tool that turns three personal inputs (age, risk tolerance, portfolio size) into a target percentage in stocks, bonds, and cash. Allocation matters because it explains roughly 90 percent of the variance in portfolio returns over time (Brinson, Hood, and Beebower 1986; replicated by Ibbotson and Kaplan 2000). Stock picking and fund choice account for the other 10 percent. Get the mix right and you have done the heavy lifting before you choose a single ticker.
The calculator uses the rule of 110 (stocks equals 110 minus your age) as a starting point and adjusts up or down for risk tolerance. The rule descends from Benjamin Graham's 1949 advice to hold a 50/50 stock-bond split and never less than 25 percent in either asset. The modern updates push equity higher because retirements now span 30 plus years (versus 15 in Graham's day) and bond yields spent 2020 to 2024 near zero, eroding their defensive role.
Start with a baseline stock weight, scale by a risk multiplier, then carve out a 5 percent cash sleeve and put the rest in bonds. The arithmetic is intentionally simple, because the value of asset allocation is in the discipline of having a target, not in calibrating it to two decimal places.
base_stock_pct = clamp(110 - age, 20, 95)
risk_multiplier = conservative: 0.80
moderate : 1.00
aggressive : 1.10
stock_pct = clamp(base_stock_pct x risk_multiplier, 10, 95)
cash_pct = 5
bond_pct = 100 - stock_pct - cash_pct
target_dollars_x = portfolio_value x x_pct / 100
Maria is 45, has a moderate risk tolerance, and a $400,000 portfolio (401(k) plus IRA plus brokerage). She does not include her $20,000 emergency fund in this calculation.
| Age | Rule of 100 | Rule of 110 | Rule of 120 | Vanguard target-date glide |
|---|---|---|---|---|
| 25 | 75% stocks | 85% stocks | 95% stocks | 90% stocks |
| 35 | 65% stocks | 75% stocks | 85% stocks | 90% stocks |
| 45 | 55% stocks | 65% stocks | 75% stocks | 82% stocks |
| 55 | 45% stocks | 55% stocks | 65% stocks | 68% stocks |
| 65 (retirement) | 35% stocks | 45% stocks | 55% stocks | 50% stocks |
| 72 plus | 28% stocks | 38% stocks | 48% stocks | 30% stocks (terminal) |
Sources: Vanguard Target Retirement glide path methodology (2026 prospectuses). Vanguard's terminal allocation is 30 stocks / 70 bonds, reached 7 years after target retirement year.
The rule of 110 says hold (110 minus your age) percent in stocks and the rest in bonds. A 40 year old holds 70 percent stocks, 30 percent bonds. The older rule of 100 was built for the 65-year retirement; rule of 110 and rule of 120 update it for 30 plus years of post-retirement life. Most major target-date funds now glide between rule of 110 in midlife and rule of 90 to 100 at retirement.
As of early 2026, Vanguard's 10 year forecast pegs US equities at 4.5 to 6.5 percent nominal, international developed at 7 to 9 percent, and US aggregate bonds at 4.3 to 5.3 percent (boosted by higher post-2022 yields). A 60/40 portfolio mixing US plus international stocks and aggregate bonds clears roughly 5.5 to 6.5 percent nominal, or about 3 to 4 percent real after 2.5 percent inflation.
Annually on a fixed calendar date is the simplest method. A 5 percent threshold (rebalance only when any sleeve drifts more than 5 percentage points from target) often produces marginally higher returns by riding momentum longer, at the cost of larger drawdowns. A hybrid (annual check plus 5 percent threshold) is what Vanguard and DFA recommend in their model portfolios.
Most models suggest 20 to 40 percent of equity in international (ex-US) stocks. Vanguard's recommended split is 60 percent US, 40 percent international (matching global market cap weights). The case for international: it reduces single-country concentration risk and currently trades at a CAPE ratio of 16 versus the S&P 500's 35, leaving more upside if multiples mean-revert.
A glide path is the schedule of how equity exposure drops as you approach retirement. Vanguard Target Retirement 2055 (someone retiring in 2055) holds about 90 percent stocks today and drops to 30 percent stocks by 7 years after retirement. A typical 'through' glide path keeps decreasing equity until age 72; a 'to' glide path stops at retirement date. Both approaches reduce sequence of returns risk in the first 5 years of retirement.
The bond tent (popularized by Michael Kitces and Wade Pfau, 2017) raises bond exposure to roughly 50 to 60 percent in the 5 years before and 5 years after retirement, then drops bonds back to 30 to 40 percent in late retirement. The shape resembles a tent. It cushions sequence of returns risk during the fragile early-retirement window without permanently capping long-run returns.
Treat REITs as part of your equity sleeve, typically 5 to 15 percent of stocks. Treat commodities (gold, broad commodity baskets) as a 0 to 10 percent diversifier with low expected return but inflation-hedge properties. The 'all weather' style portfolio (Ray Dalio, 2007) is 30 stocks, 40 long Treasuries, 15 intermediate Treasuries, 7.5 gold, 7.5 commodities.
Strategic allocation sets long-run target weights (for example 60 stocks / 40 bonds) based on your age, risk tolerance, and time horizon, and only rebalances back to those targets. Tactical allocation tilts those weights based on shorter-term valuation or macro signals (overweight value when CAPE is low, underweight credit when spreads are tight). Tactical underperforms strategic in roughly 60 percent of academic studies once costs are included.
Last updated 2026-05-28.