Bucket Strategy Calculator: Size Your Three-Bucket Retirement Portfolio

The bucket strategy divides your savings into three pools — Cash, Income bonds, and Growth — so you never have to sell stocks in a downturn to cover living expenses. This calculator does the sizing math: enter your portfolio value, annual spending, and guaranteed income (Social Security + pension), and it shows exactly how to split your money across the three buckets, with a sustainability assessment and refill schedule tailored to your numbers.

How the calculator sizes each bucket

The sizing rules follow the framework developed by Harold Evensky and later refined by Morningstar's Christine Benz and other retirement researchers.¹ Your net annual draw is the key input: it's what your portfolio actually has to fund after guaranteed income covers its share of spending.

• Bucket 1 — 18 months of net draw. The cash reserve that funds your monthly withdrawals. The conventional range is 12–24 months; 18 months is a practical midpoint that avoids both running too low (forcing emergency sales) and holding excessive idle cash earning below-inflation yields.
• Bucket 2 — 6 years of net draw. The refill engine. Conservative bonds and income assets that yield more than cash without crashing alongside equities. Six years is enough runway to wait out virtually every historical stock market downturn without tapping Bucket 3 at depressed prices.
• Bucket 3 — everything remaining. The growth engine. Invested in diversified equities for the long run. The larger this bucket relative to your total portfolio, the better your long-run real return — as long as you don't panic-sell it when markets fall, which the 7.5-year cash and bond buffer is designed to prevent.

What to hold in each bucket

How guaranteed income changes the math

The bucket strategy is sized around your net portfolio draw — not your total spending. Guaranteed income (Social Security, pension, annuities) reduces how much the portfolio has to fund each year, which makes Buckets 1 and 2 smaller in dollar terms. That's good news: smaller cash and bond reserves means more of the portfolio in Bucket 3 (growth).

Example: a couple spending $90,000/year with $28,000 in Social Security has a net draw of $62,000/year. On a $1.5M portfolio, that produces a 69% Bucket 3 allocation. Raise guaranteed income to $50,000/year (say, by delaying Social Security to 70) and the net draw drops to $40,000 — Buckets 1+2 shrink to $330,000, leaving $1,170,000 (78%) in growth assets. Strong guaranteed income doesn't just reduce spending risk; it lets you take more equity exposure safely.

The refill rules

The bucket structure is only as good as the refill discipline that maintains it. The mechanics are simple:

1. Ongoing: All monthly withdrawals come from Bucket 1. Never touch Bucket 2 or Bucket 3 for routine spending.
2. When Bucket 1 falls below 6 months of net draw: Transfer from Bucket 2 to restore 18 months. Do this regardless of market conditions — Bucket 2 is designed to be consumed.
3. When Bucket 2 falls below 2 years of net draw: Sell Bucket 3 assets to restore a full 6 years — but only when equity markets are up from your last refill point. If markets are significantly down, wait. With 2 years remaining in Bucket 2, Bucket 3 has time to recover before you're forced to sell.
4. Annual review: Reassess bucket targets if spending changes materially (healthcare cost increase, travel phase ending) or if guaranteed income changes (SS starts, annuity begins).

This sequence forces you to sell equities when they're expensive and hold them when they're cheap — the opposite of what most retirees do in a panic. The behavioral benefit is the core value of the bucket strategy.²

When to revisit bucket sizes

The initial sizing isn't permanent. Resize your buckets when:

• Guaranteed income changes — Social Security starts, a pension kicks in, or you buy an annuity. More guaranteed income shrinks the net draw and reduces Buckets 1 and 2, freeing more capital for Bucket 3.
• Spending changes materially — a major healthcare cost shift, the end of a high-travel phase, or a decision to relocate. Recompute net draw and adjust accordingly.
• Bucket 3 significantly outgrows targets — if a sustained bull market pushes Bucket 3 above 80% of the portfolio, consider whether the implied equity allocation still matches your risk tolerance. A bond tent glide path (gradually increasing Bucket 2 from age 65 to 75) is a natural companion. See the Bond Tent Guide.
• RMDs begin — required minimum distributions from traditional IRAs and 401(k)s can significantly increase taxable income from age 73 or 75 (per SECURE 2.0). RMD cash flows can supplement or replace Bucket 1 draws, allowing Bucket 1 to stay smaller. See the RMD Calculator to project your RMD schedule.

1. Morningstar — The Complete Guide to Bucket Portfolios for Retirees. Christine Benz on the three-bucket model, sizing rules, and portfolio examples. Framework reviewed 2026.
2. Kitces — Evaluating the Withdrawal Rate Sustainable with the True Bucket Strategy. Analysis of whether bucket strategies mechanically improve returns vs. total-return approaches, and where the behavioral benefit is documented.
3. IRS — Required Minimum Distributions (RMDs). SECURE 2.0 Act § 107: RMD age is 73 for those born 1951–1959; 75 for those born 1960 or later. Relevant for bucket refill strategy at RMD onset.
4. Cooley, Hubbard & Walz (1998) — Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable. The Trinity Study establishing historical success rates for various withdrawal rates and time horizons, underlying the sustainability thresholds used in the calculator output.

Bucket sizing rules (18-month cash reserve, 6-year income buffer) reflect standard planning practice as of 2026. Sustainability thresholds reference Bengen (1994) and the Trinity Study (1998).