Retirement Savings Calculator
Project the size of your retirement nest egg given your current age, retirement age, monthly contribution, and expected investment return. Use it to test whether your current saving rate is on track for the retirement income you actually want and to see how much more you need to set aside each month to close any gap.
About this calculator
The calculator computes the future value of a monthly-contribution annuity using FV = PMT × 12 × [(1 + r/12)^((retirementAge − currentAge) × 12) − 1] / (r/12), where PMT is the monthly contribution, r is the expected annual return as a decimal, and the exponent is the total number of months remaining until retirement. The PMT × 12 factor is a structural quirk of this particular form; the formula assumes contributions compound monthly at r/12 and is mathematically equivalent to summing each monthly deposit's individual future value. Starting balance is not modeled directly, so use a separate compound-interest calculator to project any existing balance and then add the two figures together for a complete picture. Edge cases: a return of 0% breaks the formula (division by zero in the r/12 term) — for that case, the result is simply PMT × 12 × years; a negative rate (real losses to inflation or fees exceeding gains) shrinks contributions over time. The biggest practical issue is that the calculator uses a constant nominal return, while real markets deliver volatile and uncertain returns: a 7% expected return is roughly the historical real (after-inflation) return of US large-cap stocks over the very long run, but the standard deviation around that mean is enormous and any given decade can produce returns wildly different from the average. For planning, run the model with two or three scenarios (a pessimistic 4%, baseline 7%, optimistic 9%) and treat the spread as a realistic range rather than betting on a single point estimate.
How to use
Example 1 — Mid-career saver. A 35-year-old plans to retire at 65, contributing $800 a month to a 401(k) and expecting a 7% nominal annual return. Enter 35 for Current Age, 65 for Retirement Age, 800 for Monthly Contribution, and 7 for Expected Annual Return. Result: approximately $976,000. Verify: r/12 ≈ 0.005833, n = 360, (1.005833)^360 ≈ 8.116, so (8.116 − 1)/0.005833 ≈ 1219.7, and 800 × 12 × 1219.7 / 12 ≈ $975,800. ✓ Over 30 years you contribute $288,000 of your own money and the rest — about $688,000 — is investment growth. Example 2 — Late-starting catch-up. A 50-year-old contributing $1,500 a month, planning to work to 70, expecting a 6% return. Enter 50, 70, 1500, and 6. Result: approximately $693,000. Verify: r/12 = 0.005, n = 240, (1.005)^240 ≈ 3.310, so (3.310 − 1)/0.005 ≈ 462.0, and 1500 × 12 × 462.0 / 12 ≈ $693,000. ✓ Of that, $360,000 is contributions and $333,000 is growth — illustrating that even a late start with disciplined saving can still produce meaningful retirement security.
Frequently asked questions
Should I use my nominal or my real (inflation-adjusted) return rate?
Most retirement calculators (including this one) use nominal returns, which means the projected balance is in future dollars, not today's purchasing power. If you plan to retire in 30 years and the calculator says $1,000,000, that future million will be worth roughly $500,000 in today's dollars assuming a steady 2.3% inflation rate. To plan in real (today's) dollars instead, subtract expected inflation from your assumed return — for example, use 4–5% if you expect a 7% nominal return and 2–3% inflation. The real-return approach makes the projected balance directly comparable to the cost of living you experience today and is usually the more honest framing for long-horizon planning.
What is the 4% rule and how does it relate to my retirement target?
The 4% rule, derived from the Bengen study and the Trinity study, says that a retiree withdrawing 4% of their initial portfolio in year one (and then adjusting annually for inflation) has historically had a high probability of the portfolio lasting 30 years across virtually any starting year in modern US market history. Working backward, that means to support $40,000 a year in retirement spending you need roughly $1,000,000 saved; to support $80,000 you need about $2,000,000. The rule has well-known limitations — it assumes a 60/40 portfolio, 30-year retirement, US historical returns, and no flexibility on spending — and many planners now use 3.3–3.5% as a more conservative starting point. But as a quick reverse-engineering tool for translating savings target into retirement income, it remains the most-cited heuristic.
Does this calculator account for employer 401(k) matches?
No — it only takes a single monthly contribution amount. If your employer matches part of your contribution, add the match into the monthly contribution field. For example, if you contribute $500 a month and your employer matches dollar-for-dollar up to 4% of a $7,500 monthly salary ($300 match), enter $800 as the monthly contribution. Employer matches are effectively a 50–100% instant return on the matched portion, so failing to capture at least the full match is widely considered one of the biggest savings mistakes Americans make — Vanguard estimates roughly a third of eligible 401(k) participants leave some match money on the table each year. Also add any traditional or Roth IRA contributions you make outside the 401(k) into the monthly figure for a total household savings rate.
What are the most common mistakes people make with retirement projections?
The biggest is assuming long-term average returns (7–10% nominal for US equities) without acknowledging the wide variance — a single bad decade early in retirement, called sequence-of-returns risk, can permanently impair a portfolio that would otherwise have lasted. The second is ignoring inflation by working in nominal dollars and feeling rich about a $2 million projection that buys only $1 million of today's lifestyle. The third is assuming constant contributions for 30 years; real careers have layoffs, salary jumps, kids, divorce, and other discontinuities that disrupt steady contributions. The fourth is forgetting taxes: traditional 401(k) and IRA balances are pre-tax, so a $1 million traditional balance produces only $700–$800K of after-tax retirement spending. Finally, people often anchor on the calculator's single-point estimate rather than running multiple scenarios to understand the range of outcomes they might actually face.
When should I not rely on this calculator?
Do not use it for detailed retirement income planning — for that you need a model that handles drawdown, Social Security timing, Medicare costs, tax brackets across account types (traditional, Roth, taxable), and probability-of-success simulation under variable market returns (Monte Carlo). Skip it if your contributions vary significantly year to year, if you expect a large windfall (inheritance, business sale, RSU vest) that changes the trajectory, or if you have a defined-benefit pension that adds non-portfolio income in retirement. It is also a poor fit for non-US retirement systems with different tax structures and social safety nets — the underlying math is universal but the practical planning recommendations differ. For decisions with real money at stake, use this as a starting point and then validate against a more detailed planner or work with a fee-only fiduciary advisor.