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Guyton-Klinger guardrail simulator

The Guyton-Klinger guardrails adjust spending up or down when the current withdrawal rate crosses bands above or below the starting rate. This simulator shows how the rules respond in down, flat, and up markets.

Year 1 baseline
$55,000/yr
5.5% of $1,000,000. Triggers: cut at ≥ 6.6%; raise at ≤ 4.4%.
30% market drop, +3% inflation step-up
$50,985
Current rate: 8.09%

Capital Preservation Rule fired — current rate 8.09% ≥ upper trigger 6.60%. Cut withdrawal by 10%.

Flat market, +3% inflation step-up
$56,650
Current rate: 5.67%

Inside guardrails — no adjustment. Continue current withdrawal (with inflation step-up).

+50% market growth, +3% inflation step-up
$62,315
Current rate: 3.78%

Prosperity Rule fired — current rate 3.78% ≤ lower trigger 4.40%. Raise withdrawal by 10%.

Educational simulation; doesn't include the other two GK rules (Withdrawal Rule + Inflation Rule). The original paper: Guyton & Klinger 2006, Journal of Financial Planning.

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FAQ

What is Guyton-Klinger?
A 2006 paper by Jonathan Guyton + William Klinger introducing four "decision rules" for retirement withdrawals. The two most important: Capital Preservation (cut spending if portfolio drops too much) and Prosperity Rule (raise spending if portfolio grows enough).
Why a higher starting rate than 4%?
The dynamic rules let you start higher (5–5.5% in their original paper) because spending will adjust if the portfolio underperforms. Fixed-4% retirees historically die with much more money than they started with, meaning they could have spent more.
How does this compare to VPW?
VPW (Variable Percentage Withdrawal, Bogleheads) recalculates the safe withdrawal each year based on current balance × age-specific divisor. More volatile spending, but mathematically can't deplete. Guyton-Klinger smooths spending more but theoretically can run out in extreme scenarios.

Educational guidance only. Not legal, tax, or individualized investment advice. We do not recommend individual securities or guarantee outcomes.