Retirement Calculator

This is a retirement-corpus projection. You enter your current age, the age you want to retire at, what you've already saved, what you can contribute each month, and the rate of return you expect. It compounds those inputs forward to the target age and shows the corpus you'll have. It also shows the gap between what you're on track for and a rule-of-thumb target.

The most-cited target is the 25× rule. Whatever you spend in a year, multiply by 25. That's roughly the corpus you need to live off a 4% safe withdrawal rate. Spend $40,000 a year? Aim for $1 million. The 4% rule has limits in long retirements and falling-market scenarios, but it's a useful first-pass target.

The math combines two things. Your existing savings compound at the expected rate. Your monthly contributions compound as a recurring annuity. The final corpus is the sum of both:

Where S is current savings, P is monthly contribution, r is the monthly rate, and n is the number of months between now and retirement.

Worked example: 32 years old, retiring at 60, $50,000 saved, $800/month contributions, 8% annual return. n = 336 months, r = 0.08/12 ≈ 0.00667. Existing savings compound to roughly $463,000. Monthly contributions compound to roughly $1.17 million. Total corpus ≈ $1.63 million. The corpus would let you spend about $65,000/year under the 4% rule.

How big does your corpus need to be? The most widely cited answer is the 4% rule: you can safely withdraw 4% of your starting portfolio each year, adjusted for inflation, without running out of money over a 30-year retirement. The corollary: target a corpus of 25 times your annual spending.

If you spend $40,000/year, aim for $1,000,000. If you spend $80,000/year, aim for $2,000,000. The 4% rule comes from the Trinity study (Bengen, 1994) which back-tested a 60/40 portfolio against US market history — it has held up reasonably well in international and longer-horizon replications, but bear in mind it's a guideline, not a guarantee.

For retirements longer than 30 years (FIRE), drop to a 3.25–3.5% withdrawal rate. The extra cushion compensates for sequence-of-returns risk over a longer horizon.

The projection above uses your nominal return rate. To see your corpus in today's dollars — what it will actually buy — subtract your expected inflation rate from the return rate before running the calculator.

If you expect 8% nominal returns and 3% inflation, plug in 5% instead of 8%. The result is your real corpus — slightly more sobering, but more honest about what your savings will buy in retirement. Most retirement planners default to nominal numbers because they look bigger; the real number is what matters.

Two retirees with identical average returns can have very different outcomes depending on when the good and bad years arrive. Sequence-of-returns risk is the danger of a major drawdown in the first decade of retirement: selling shares to fund living costs while prices are depressed locks in losses that the portfolio never fully recovers from.

Defences: hold 2–3 years of spending in cash or short bonds (the "bond tent" strategy), maintain a flexible withdrawal rate (cut spending in down years), and keep some ongoing income (part-time work, social security) so the portfolio doesn't bear the full burden in a crash.

US savers can contribute extra to retirement accounts starting at age 50:

• 401(k): extra $7,500/year on top of the $23,000 base limit (2025) → $30,500 total.
• IRA: extra $1,000/year → $8,000 total.
• HSA (if eligible): extra $1,000/year for those 55+.

Catch-up contributions can be the difference between retiring on schedule and working an extra five years. If you're behind, max them out.