how long will the money last calculator

What This Money Longevity Calculator Tells You

The goal of this calculator is simple: estimate how long your savings can support your lifestyle. It is useful for retirement planning, career breaks, early retirement (FIRE), emergency funds, and anyone evaluating withdrawal strategies.

You enter your current nest egg, monthly expenses, additional monthly income, expected investment return, and inflation assumptions. The tool then simulates your money month by month until either:

• Your balance reaches zero (money runs out), or
• You hit the projection limit you selected.

How the Calculator Works (Behind the Scenes)

Monthly Simulation Method

Instead of using a rough yearly estimate, this version models your plan every month:

• Balance grows by a monthly return based on your annual return assumption.
• Monthly income is added.
• Monthly spending is subtracted.
• Spending increases over time using your inflation rate.

This approach gives a more realistic savings depletion estimate than a simple “balance divided by expenses” formula.

Inputs That Matter Most

• Monthly spending: Usually the biggest driver of how long money lasts.
• Investment return: Higher return can meaningfully extend longevity, but returns are uncertain.
• Inflation: Rising costs quietly shorten portfolio lifespan.
• Other income: Social Security, pension, part-time work, rental income, etc.

Example Scenario

Suppose you have $500,000 in savings, spend $3,500 per month, and receive $1,000 per month from other sources. If your portfolio earns 5% annually and inflation is 2.5%, your money may last much longer than expected compared to a zero-growth estimate.

Try changing one input at a time. You will quickly see how sensitive retirement drawdown plans are to spending habits, market returns, and inflation pressure.

Ways to Make Your Money Last Longer

• Reduce baseline monthly expenses before market downturns force difficult decisions.
• Delay large discretionary purchases during high inflation periods.
• Keep a diversified allocation aligned with your risk tolerance and time horizon.
• Use a flexible withdrawal approach instead of a fixed spending amount in all markets.
• Consider part-time or seasonal income to reduce withdrawals in early retirement years.

Important Planning Notes

This Is an Estimate, Not a Guarantee

Real life is messier than any calculator. Markets are volatile, tax rules change, health costs can spike, and life plans evolve. Use this as a planning tool, then stress-test with conservative assumptions.

Run Multiple Cases

A good practice is to model three scenarios:

• Optimistic: Higher returns, lower inflation.
• Base case: Moderate assumptions.
• Conservative: Lower returns, higher inflation, higher spending.

If your plan works even in conservative settings, it is generally more resilient.

Frequently Asked Questions

Is this a retirement calculator?

Yes, it works as a retirement spending calculator and a savings depletion calculator. It estimates portfolio longevity under recurring withdrawals.

Does it account for inflation?

Yes. Monthly spending increases over time according to the annual inflation input.

Can money last forever?

In some scenarios, yes. If investment growth plus recurring income consistently cover spending, your balance may continue growing and never deplete within your selected time horizon.

Bottom Line

A “how long will the money last” calculator helps turn vague financial anxiety into concrete numbers. Start with realistic inputs, review the result, and adjust spending, income, or return expectations until your plan is sustainable. Revisit the numbers at least annually so your strategy stays aligned with reality.