How Long Will My Money Last? Use This Calculator to Find Out
Corrections to make in the article:
- Life expectancy paragraph: Remove/correct the unsupported "men to 91, women to 93" claim. Replace with a supportable, more general statement about planning horizon.
- 80/20 portfolio 4.4% / target-date 3.5% claims: Remove or soften these unsubstantiated specific figures.
- "70%" → "nearly 70%" (minor accuracy fix to match the Morningstar source).
- Add financial disclaimer at the bottom of the article.
title: "How Long Will My Money Last Calculator: Why Retirees Need to Stress-Test Their Portfolios" description: "Use a how long will my money last calculator to stress-test your retirement savings. Learn why withdrawal sustainability depends on more than one number."
How Long Will My Money Last Calculator: Why Retirees Need to Stress-Test Their Portfolios
If you've ever typed "how long will my money last calculator" into a search bar, you understand the core anxiety of retirement planning. You have a balance, a monthly need, a rough sense of how many years remain — and you want to know if it adds up.
The honest answer: it depends on far more than a single calculation can capture.
The Problem with a Simple Retirement Calculator
Most basic tools work the same way: enter your balance, monthly withdrawal, and assumed rate of return, and they return an estimated depletion date.
That approach has a fundamental flaw. Real markets don't deliver smooth, predictable returns — they lurch up and down, and the order of those lurches matters enormously. A calculator assuming 7% annual growth every year will give you a very different answer than one that stress-tests your portfolio against historical and simulated market conditions. The gap between those two answers is where retirees get into trouble.
How Long Does Retirement Money Actually Need to Last?
Most financial planners recommend planning for a retirement horizon of 25 to 30 years or more — and often suggest planning to age 90 or 95 to avoid the risk of outliving your savings. The right target depends on your health, family history, and retirement age.
That's a long time for a portfolio to survive market cycles, inflation, and shifting spending needs. A calculator that doesn't model that full span leaves critical gaps in your planning.
The 4% Rule: Useful Starting Point, Not a Guarantee
The 4% rule — withdraw 4% of your portfolio annually, adjusted for inflation — has been a cornerstone of retirement planning for decades. It assumes roughly a 50/50 stock-bond split. But there are no guarantees your assets last 30 years even if you follow it.
More recent research has revised the number downward. Morningstar's 2024 analysis puts the highest safe starting withdrawal rate at 3.7% for a retiree seeking fixed real withdrawals at a 90% success rate over 30 years.
Your sustainable withdrawal rate will vary based on factors you can't control — lifespan, inflation, market returns — and factors you can, like retirement age and asset allocation.