How Long Will Money Last Retirement Calculator

Determine how long your retirement savings will last using this calculator. Simply enter your current savings, expected annual withdrawal, and expected annual return, then click Calculate to see your results.

How This Calculator Works

This retirement duration calculator estimates how long your savings will last based on your expected withdrawals and investment returns. The calculation assumes your money grows at a steady annual rate while you withdraw a fixed amount each year.

The calculator uses a simple formula to determine when your balance will reach zero. It doesn't account for inflation, taxes, or changes in your spending habits, so the result is an estimate.

The Formula

The core calculation uses this formula:

Years = log(Withdrawal / (Withdrawal - (Savings × Return))) / log(1 + Return)

Where:

Years is the estimated duration your money will last
Withdrawal is your annual spending amount
Savings is your current retirement balance
Return is your expected annual investment return (as a decimal)

This formula assumes your money grows at a constant rate while you make fixed withdrawals each year.

Worked Example

Let's say you have $500,000 saved for retirement, plan to withdraw $40,000 per year, and expect a 4% annual return on your investments.

Using the formula:

Years = log(40000 / (40000 - (500000 × 0.04))) / log(1 + 0.04) Years ≈ log(40000 / 38000) / log(1.04) Years ≈ 1.047 / 0.0392 ≈ 26.68 years

This means your $500,000 could last about 26.68 years with these assumptions.

Key Assumptions

This calculator makes several important assumptions:

Your money grows at a constant annual rate
You withdraw a fixed amount each year
There are no changes to your spending or investment strategy
Inflation and taxes are not factored into the calculation

Real retirement planning should consider these factors, which this calculator doesn't account for. Consult with a financial advisor for personalized advice.

Frequently Asked Questions

How accurate is this retirement duration calculator?

This calculator provides an estimate based on your inputs and assumptions. Real retirement planning requires considering additional factors like inflation, taxes, and changes in your financial situation.

What if my spending changes over time?

The calculator assumes fixed annual withdrawals. If your spending changes, you may need to adjust your savings or investment strategy accordingly.

Does this calculator account for inflation?

No, this calculator doesn't adjust for inflation. You may need to increase your withdrawals over time to maintain your purchasing power.

What if my investments don't perform as expected?

The calculator uses your expected annual return. If your investments perform worse, your money may last longer, but you may need to adjust your spending or savings.