Retirement Gap Calculator
Find out whether you are on track for retirement, how big the shortfall is, and how much more to save each month to close the gap.
How the gap is measured
First the tool grows your savings and monthly contributions to your retirement date. Then it works out how much you need: the income you want, minus Social Security or a pension, raised for inflation, then divided by the withdrawal rate (4% means you need 25 times the yearly shortfall). The difference between the two is your gap.
Use realistic returns and be careful with the withdrawal rate. For a deeper test of how likely your money is to last, try the Monte Carlo retirement calculator.
Last reviewed November 2026. Formulas are standard and shown in the sections above; results are estimates.
Tips and common mistakes
- Check this every year and adjust.
- Working two more years often closes a large gap.
- Include Social Security or pension income to avoid over saving.
Learn more
Frequently asked questions
What return should I use?
A cautious long-term estimate is 5% to 7% a year before inflation.
What is a safe withdrawal rate?
4% is a common starting rule for a 30-year retirement, but lower is safer for longer ones.
Does it include taxes?
No. Withdrawals from tax-deferred accounts are taxed, so treat the target as before tax.
What if the result is a surplus?
You could retire earlier, spend more or reduce saving.
Money guides for this topic
All guides →Will My Retirement Money Last? Understanding the Odds
Why a fixed 4% rule is only a starting point, what sequence-of-returns risk is, and how simulations show the chance of success.
Read guide →Investing for Beginners: A Simple Plan with the Numbers
A plain-English starter plan for investing: low-cost index funds, regular contributions and why fees matter.
Read guide →Compound Interest Explained (and Why Starting Early Wins)
How compound interest works, the rule of 72, and a simple example showing why time matters most.
Read guide →Related calculators
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Estimate your retirement pot and the yearly income it could support using the 4% rule.
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Find how much you need to retire early (FIRE) and how many years it will take.
Open calculator →Roth vs Traditional IRA Calculator
Compare Roth and Traditional retirement accounts after tax, based on your tax rate now and in retirement.
Open calculator →Results are estimates and not financial advice.