Retirement Investment Calculator
✦ Finance & MoneyUse this free retirement investment calculator to see how much your savings grow to retirement age — with monthly contributions, an optional annual increase, inflation adjustment and a drawdown phase to estimate how long the balance will last.
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- ✓ Nothing you type is stored
- ✓ No sign-up required
- ✓ Formula and sources shown
The formula
Retirement accumulation with regular contributions
Accumulation:
B_t = P x (1 + r/n)^(nxt) + PMT_y x [(1 + r/n)^(nxt) - 1] / (r/n)
where PMT_y = monthly contribution x (1 + g_c)^(y-1) x n
Drawdown (monthly, withdrawal raised once a year by inflation i):
B_m = B_(m-1) x (1 + r_m) - W x (1 + i)^floor((m-1)/12)
with i = 0: m = -ln(1 - B x r_m / W) / ln(1 + r_m), never depleting when W ≤ B x r_mP = starting savings; r = net annual return (= stated return - annual fee); n = compounding periods per year (12 monthly, 1 annual); t = years to retirement; PMT_y = contribution per compounding period in year y; g_c = annual contribution-increase rate; B = balance at retirement; r_m = net monthly return (the same return minus fee, ÷ 12); W = monthly withdrawal in the first year of retirement; i = the inflation rate under Advanced. Contributions are added end-of-period by default (ordinary annuity); switch to beginning-of-period in the timing toggle. Inflation also divides the nominal balance by (1 + i)^t for the "After inflation" figure.
Calculating it by hand
- Enter your current age and the age at which you plan to retire — this sets the accumulation horizon.
- Enter your current retirement savings balance as the starting amount (0 if none).
- Enter your planned monthly contribution (0 if none).
- Enter an annual return rate — a hypothetical assumption, not a forecast. The scenario cards show the result 2 points either side.
- Open "Advanced assumptions" to add an annual contribution increase, a fund expense ratio, an inflation rate and a scenario spread.
- Open "Drawdown phase" to enter the monthly withdrawal for your first year of retirement and see how long the balance lasts.
- The estimate updates on every input change; a blank or non-numeric field shows a message instead of a result.
Worked examples
$0 start, $500 a month for 30 years at 7%, monthly compounding, no fee
r/n = 0.07 / 12 = 0.005833; n × t = 360 periods.(1.005833)^360 = 8.11650.Contributions grow to 500 × [(8.11650 − 1) / 0.005833] = 500 × 1,219.97 = $609,985.Starting savings contribute $0 × 8.11650 = $0.Total paid in: $500 × 360 = $180,000; growth $429,985.
Balance at retirement: $609,985; total contributions $180,000; growth $429,985.
$50,000 start, no contributions, 20 years at 6%, compounded annually
(1.06)^20 = 3.20714.Balance = $50,000 × 3.20714 = $160,357.
Balance at retirement: $160,357 — all of the $110,357 above the starting amount is growth.
$10,000 start, $300 a month rising 3% a year, 25 years at 7%, monthly
Year 1: $300 a month. Year 2: $309. Year 5: $300 × 1.03^4 = $337.65.Year 1 deposits grow by year end to 300 × [(1.005833)^12 − 1] / 0.005833 = 300 × 12.3926 = $3,717.78.Each later year's deposits are 3% larger and compound for the years that remain; the starting $10,000 grows to $10,000 × (1.005833)^300 = $57,254.Total paid in over 25 years: $131,253 plus the $10,000 start; the balance at 55 is $376,516.The same $10,000 start with a flat $300 a month reaches $300,276, so the 3% increase adds $76,241.
Balance at retirement: $376,516 — 25% more than the $300,276 a flat $300 a month reaches from the same start.
Methodology
How retirement savings actually grow
Most people underestimate how much the contribution-increase rate — not just the return rate — shapes the final balance. Compounding works on contributions you have not yet made, and a 3% annual raise on your contributions compounds the same way your return does.
Read sources and limitsHow do retirement savings compound differently from a lump sum?
A lump sum grows along a single exponential curve. Retirement savings grow differently because you keep adding to the balance, and each new contribution starts earning its own return. The result has two parts: your existing savings compounding at the net rate, and every monthly contribution compounding for the months left until retirement.
Over long horizons the contributions dominate. At the page's defaults — $10,000 saved plus $500 a month for 35 years at 7% — the contributions grow to $900,527 of the $1,015,589 total (89%), and the starting $10,000 to $115,062. Adding years or raising contributions moves the result far more than a slightly higher assumed return.
The composition bar under the headline splits the result into starting savings, contributions and growth, and the annual ledger shows the year in which growth overtakes what you have paid in.
How much difference does increasing contributions by 3% a year make?
More than most people expect. If you raise your contribution by 3% each year, every larger deposit also earns the full compound return for the years that remain, so the effect builds on two fronts at once: more money goes in, and the extra money has decades to grow. The field is under Advanced and defaults to 0%.
From a $0 start, $500 a month for 30 years at 7% grows to $609,985. Raising the contribution 3% a year grows it to $833,580 — $223,595 more, a 37% larger balance — while the total paid in rises from $180,000 to $285,452. A salary-linked increase of 2–4% is a realistic assumption to test.
What do inflation-adjusted retirement savings mean?
A balance of $1,000,000 in 30 years will not buy what $1,000,000 buys today. At 2.5% annual inflation its purchasing power is about $476,743 in today's dollars — less than half. Inflation does not shrink the nominal balance; it shrinks what the balance can pay for, which is what matters in retirement.
Enter an inflation rate under Advanced and the calculator divides the nominal balance by (1 + i)^t to show an "After inflation" figure beside it; the accumulation arithmetic itself is unchanged. The Federal Reserve aims for 2% inflation over the longer run, so 2–3% is a reasonable range to test. The same rate also raises your drawdown withdrawal each year.
How long will my retirement savings last in the drawdown phase?
Open "Drawdown phase" and enter the monthly withdrawal for your first year of retirement. The balance keeps earning the same net return (after the annual fee), and the withdrawal rises once a year by your inflation rate — the 4%-rule pattern. The calculator steps the balance month by month and reports when it runs out.
With inflation at 0% the answer has a closed form, m = −ln(1 − B × r_m / W) / ln(1 + r_m), and a withdrawal no larger than the monthly earnings (W ≤ B × r_m) never depletes the balance: $500,000 at a 5% net return earns $2,083.33 a month. With inflation above 0%, even a withdrawal below the earnings eventually overtakes them.
The drawdown does not model Social Security, required minimum distributions, account types or taxes on withdrawals. It is a single-rate projection of how long a balance lasts under a fixed spending pattern, not a retirement income plan.
What does this retirement calculator not model?
Social Security is not modelled: benefits depend on your full earnings history, filing age and the SSA's benefit formula, none of which can be inferred from these inputs, and the SSA's own estimator gives that figure. Employer match, tax treatment (Roth or traditional) and required minimum distributions are outside the model too.
Annual contribution limits are not enforced. For 2026 the 401(k) employee deferral limit is $24,500 (plus an $8,000 catch-up at 50 and over, or $11,250 at ages 60–63) and the IRA limit is $7,500 (plus $1,100 at 50 and over), per IRS Notice 2025-67.
This calculator provides educational estimates based on the assumptions you enter. It is not investment, tax, legal or financial advice. Investing involves risk, including possible loss of principal; actual results will differ.
Retirement Investment questions
How much will my retirement savings grow?
It depends on your starting balance, your contributions, your net return and the number of years. $10,000 saved plus $500 a month for 30 years at 7% grows to $691,150, of which $501,150 is growth; over 35 years, the page's defaults, it reaches $1,015,589. Enter your own numbers to see your projection; any assumed rate is a hypothesis, and actual returns will differ.
How much do I need to save for retirement?
A common rule of thumb is 25 times the annual spending you will draw from savings — the inverse of the 4% withdrawal rate from Bengen (1994) and the "Trinity study" (Cooley, Hubbard and Walz, 1998). $40,000 a year means a $1,000,000 target. Use this calculator to see whether your savings, contributions and assumed return reach your target; it does not model Social Security, taxes or flexible spending, and the rule is a guideline, not a guarantee.
What annual return should I assume for retirement planning?
There is no single correct figure. Diversified stock portfolios have historically out-earned bonds and cash over long periods, with wide swings in individual years; many planners test a nominal 5–7% for a balanced portfolio, lower for a cautious one. The scenario cards show your result 2 points either side of the base rate. FINRA and the SEC caution that past returns do not guarantee future results, so treat any rate as a test, not a forecast.
What is the effect of increasing contributions by 3% per year?
From a $0 start, $500 a month for 30 years at 7% grows to $609,985 with flat contributions and to $833,580 with a 3% annual increase — $223,595 (37%) more, from paying in $285,452 instead of $180,000. Each larger deposit also compounds for the years that remain. Set "Annual contribution increase" under Advanced; matching it to your expected raise keeps your savings rate steady as income grows.
How do I estimate how long my retirement savings will last?
Open "Drawdown phase" and enter the monthly withdrawal for your first year of retirement and a horizon. The balance keeps earning your net return, the withdrawal rises each year by the inflation rate under Advanced, and the calculator reports the month the balance runs out, or that it lasts the whole horizon. It does not model Social Security, taxes, required minimum distributions or variable spending.
Does this calculator include Social Security?
No — deliberately. Social Security benefits depend on your highest 35 years of indexed earnings, your filing age and the SSA's benefit formula, none of which can be computed from age and contribution inputs. Use the Social Security Administration's estimator for that figure, then subtract it from the income your savings must provide before setting a drawdown withdrawal.
What is the difference between nominal and inflation-adjusted retirement savings?
The nominal balance is the dollar amount your account would hold; the inflation-adjusted balance converts it to today's purchasing power. At 2.5% inflation over 30 years, $1,000,000 is worth about $476,743 in today's dollars ($1,000,000 ÷ 1.025^30). Enter an inflation rate under Advanced to see both; the gap is price-level change, not real growth.
What is the 4% rule?
The 4% rule is a guideline for spending from savings: withdraw 4% of the starting balance in the first year, then raise that dollar amount with inflation each year. On $1,000,000 that is $40,000 in year one ($3,333 a month), rising to $41,200 in year two at 3% inflation. It came from historical tests of U.S. stock-and-bond portfolios over 30-year retirements (Bengen, 1994). Set the drawdown withdrawal and an inflation rate here to run the same pattern on your own balance and return.
How much do I need to retire on $60,000 a year?
Under the 4% rule, multiply the amount that must come from savings by 25. If all $60,000 comes from your portfolio, the target is $1,500,000; if Social Security or a pension covers $24,000, only $36,000 is needed and the target falls to $900,000. In future dollars, $1,500,000 today is about $2,709,167 in 20 years at 3% inflation. A more cautious 3.5% withdrawal rate raises the $60,000 target to about $1,714,286.
What are the 2026 401(k) and IRA contribution limits, including catch-up contributions?
For 2026 the employee deferral limit for 401(k), 403(b), most 457 plans and the TSP is $24,500. Savers aged 50 and over can add an $8,000 catch-up, and those aged 60–63 can instead add $11,250. The IRA limit is $7,500, with a $1,100 catch-up at 50 and over (IRS Notice 2025-67). Employer matches do not count against the employee limit. This calculator does not enforce the limits, so check your monthly contribution against them.
Does it matter whether my savings are in a Roth or a traditional account?
For the growth projection, no — the same contributions at the same return produce the same balance. The difference is what you keep: traditional 401(k) and IRA withdrawals are taxed as ordinary income, so a $1,000,000 traditional balance supports $780,000 of spending at a 22% average rate, while qualified Roth withdrawals are tax-free because contributions were taxed up front. Which comes out ahead depends on your tax rate now versus in retirement.
Why does a 1% fee make such a difference to retirement savings?
Because the fee comes off the return every year, and the lost return compounds. $10,000 plus $500 a month for 35 years at 7% grows to $1,015,589; at a 6% net return after a 1% fee it grows to $793,591, so the fee costs $221,998 — more than the $210,000 you would pay in over those 35 years. Enter your fund's expense ratio under Advanced to see your own figure.
Source notes
Method, sources & limitations
Every figure on this page comes from the formula above applied to the values you enter. Nothing is estimated from market data, and no result is a forecast. These are the sources behind the method and any fixed figures it uses:
- IRS — 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500 (Notice 2025-67)
- U.S. Department of Labor, EBSA — Savings Fitness: A Guide to Your Money and Your Financial Future
- U.S. Securities and Exchange Commission (Investor.gov) — Compound interest calculator (formula reference)
- Board of Governors of the Federal Reserve System — Why does the Federal Reserve aim for inflation of 2 percent over the longer run?
- Social Security Administration — Retirement benefits estimator
Educational information only. Results are estimates produced from the assumptions you enter, and are not financial, tax, legal or medical advice. Check anything that matters against a qualified professional and the cited sources.