How to Calculate Your Asset Allocation Glide Path Toward Retirement

What a Glide Path Actually Is

A glide path is a pre-scheduled reduction in equity allocation that begins years before retirement and continues into it. The core logic is simple: equities generate higher long-run returns, but they carry volatility that a working investor can absorb through future contributions. A retiree with no paycheck cannot wait out a 30% drawdown. The glide path trades some expected return for time stability as the distribution phase approaches.

Target-date funds embed this mechanic automatically. A Vanguard Target Retirement 2035 Fund holds roughly 68% equities as of 2026. By 2035, that drops to approximately 50%. By 2065, it reaches around 30%. Individual investors can replicate this structure manually across a 401(k), a Roth IRA, and a taxable brokerage account, with more control over the specific allocation and the pace of the shift.

The Linear Glide Path Formula

The simplest calculation uses a straight-line reduction from a starting equity percentage to an ending equity percentage over a fixed number of years.

The formula is:

Equity % at Age X = Start Equity % - ((X - Start Age) / (End Age - Start Age)) x (Start Equity % - End Equity %)

Define your three inputs before running any numbers:

• Start equity %: Your current equity allocation (e.g., 90%)
• End equity %: Your target equity allocation at or shortly after retirement (e.g., 40%)
• Time horizon: Years from now until your target retirement age

Worked Example 1: Investor at Age 45, Retiring at 65

An investor is 45 years old, holds 90% equities across a $600,000 portfolio, and plans to retire at 65. The target allocation at retirement is 40% equities. The time horizon is 20 years. The annual reduction rate is (90% - 40%) / 20 = 2.5 percentage points per year.

At age 50: 90% - (5 x 2.5%) = 77.5% equities, or $465,000 in equities on a $600,000 base. At age 60: 90% - (15 x 2.5%) = 52.5% equities. At age 65: 40% equities, or approximately $480,000 in equities assuming 6% annualized growth to a $1.2M portfolio.

Each year, the investor rebalances to the formula target. No guesswork. No market-timing.

The Curved Glide Path: Front-Loading the Shift

A linear path reduces equity exposure at the same rate every year. A curved path accelerates the reduction in the final 10 years, when sequence-of-returns risk peaks. This approach holds more equities for longer, capturing more growth during the accumulation phase, then reduces exposure sharply as retirement nears.

A simple exponential approximation applies a steeper annual cut in the back half of the glide path. Instead of a flat 2.5 percentage points per year, an investor might reduce by 1 percentage point annually from age 45 to 55, then by 4 percentage points annually from age 55 to 65.

Worked Example 2: Investor at Age 52, Retiring at 62

An investor is 52 years old with a $900,000 portfolio and a 10-year runway to retirement. The current allocation is 75% equities ($675,000). The target at retirement is 35% equities. The total reduction needed is 40 percentage points over 10 years. Under a curved structure, the investor reduces by 2 percentage points annually from age 52 to 57 (10 points total), then by 6 percentage points annually from age 57 to 62 (30 points total).

At age 57: 75% - 10% = 65% equities. At age 62: 65% - 30% = 35% equities, or roughly $490,000 in equities on a projected $1.4M portfolio assuming 5.5% annualized growth.

Compared to the linear path, the curved version holds approximately 4 to 7 percentage points more in equities through the mid-50s. On a $900,000 starting balance growing at 5.5%, that additional equity exposure adds an estimated $18,000 to $35,000 in expected portfolio value at age 57, before the sharper deceleration takes effect.

Where to Apply the Reduction

Rebalancing across multiple account types requires sequencing by tax efficiency. The correct order prioritizes the accounts with the least tax friction.

Inside a 401(k) or a traditional IRA, rebalancing creates no taxable event. Sell equities and buy bonds freely. Inside a Roth IRA, the same rule applies. Inside a taxable brokerage account, selling appreciated equities triggers capital gains. Reduce equity exposure there last, or use new cash contributions to purchase bonds rather than selling existing positions.

An investor with $400,000 in a 401(k), $200,000 in a Roth IRA, and $300,000 in a taxable account should execute all rebalancing in the 401(k) and Roth IRA first. If additional rebalancing is needed in the taxable account, long-term capital gains rates of 15% to 20% apply to positions held more than 12 months. On a $50,000 equity reduction in a taxable account with a $20,000 embedded gain, the federal tax cost is $3,000 to $4,000 at the 15% to 20% rate.

Recalibrating After a Major Market Move

A glide path is a schedule, not a rigid rule. A significant equity drawdown can pull your actual allocation below the formula target. A 25% equity market decline on a 70/30 portfolio moves you to roughly 64/36. Rebalancing back to 70/30 in that environment buys equities at lower prices, which improves forward returns.

The discipline is annual review, not daily monitoring. Set a calendar reminder every January. Compare your actual allocation to the formula target for your current age. Rebalance if the gap exceeds 5 percentage points in either direction. Document each year's target and actual figures in a spreadsheet so you can audit the path over time.

Run Your Numbers Before the Market Does It for You

A glide path calculated now, before the next 20% drawdown, costs nothing. A glide path built in response to a drawdown locks in losses. The difference between a planned 35% equity position at age 62 and an unplanned 60% equity position after refusing to rebalance is potentially $150,000 to $300,000 in retirement income stability on a $1M portfolio.

The CalcMoney Retirement Calculator lets you input your current age, target retirement age, current allocation, and target allocation. It outputs the annual equity percentage for every year between now and retirement, plotted against your projected portfolio balance. Run the linear path first. Then test the curved version. The gap between the two approaches will be visible in less than two minutes.

Build your personal glide path in the CalcMoney Retirement Calculator →

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Results are estimates for informational purposes only. Consult a licensed financial professional before making financial decisions.