Retirement Calculator

A retirement plan has two halves: the years spent building the balance and the years spent drawing it down. Most calculators stop at the first half and show a large number that feels like an answer, without checking whether that number pays for the life it is supposed to fund.

Balance at 65

$1,048,975.44

$500,091 in today money, after 30 years of saving

Nest egg the spending needs: $900,000.00
Shortfall in today money: $399,908.63
Money still lasts: To age 90
Growth share of the balance: 67.4%

Where the balance at retirement comes from

Money you put in$342,090.17
Growth$706,885.27

Contributions stop at retirement; the growth slice keeps working while the money is invested, which is why the saving habit matters more than the timing of any single deposit.

Every fifth year on the way there

Age	Start of year	Paid in	Growth	End of year	In today money
40	$96,920	$7,794	$6,196	$110,910	$98,028
45	$177,782	$8,605	$11,206	$197,592	$154,359
50	$291,748	$9,500	$18,260	$319,508	$220,610
55	$450,879	$10,489	$28,103	$489,470	$298,709
60	$671,491	$11,581	$41,740	$724,812	$390,957
65	$975,656	$12,786	$60,534	$1,048,975	$500,091

The growth column overtakes the paid-in column about two thirds of the way through a 30-year plan. That crossover is the whole argument for starting early.

What the same income needs at other withdrawal rates

Withdrawal rate	Nest egg needed	Against your balance
3%	$1,200,000	−$699,909
3.5%	$1,028,571	−$528,480
4%	$900,000	−$399,909
4.5%	$800,000	−$299,909
5%	$720,000	−$219,909
6%	$600,000	−$99,909

A lower withdrawal rate is a safety margin, not a rule: it means a larger balance, more left for heirs and a better chance of surviving a bad first decade.

How long the balance lasts at other spending levels

Spending	Per year	Years of withdrawals	Money runs out
−20%	$28,800	25	Still funded at 90
−10%	$32,400	25	Still funded at 90
As planned	$36,000	25	Still funded at 90
+10%	$39,600	25	Still funded at 90
+25%	$45,000	25	Still funded at 90

Withdrawals are taken at the start of each year and rise with inflation at 2.5%, which is the cautious order: a bad first decade hurts more than a bad last one.

The plan is short by $399,909 in today money, which means a balance at retirement of about $1,887,811 in the money of the day. Closing the gap needs roughly $1,580 a month instead of $600 — about 263% of the current deposit, or a later retirement age, or a lower planned spending figure.

JavaScript is off, so the values above are the built-in defaults. Every formula used on this page is documented below, so you can still follow the maths by hand.

This one does both. It projects the balance from your current savings and monthly deposits, converts the result into today money, works out the nest egg your planned spending requires at your chosen withdrawal rate, and simulates the withdrawals year by year, with inflation, to see how long the money actually lasts.

How this retirement calculator works

Building the balance

Each month the existing balance grows at the monthly equivalent of the annual return, then the deposit is added. Deposits are assumed to be made at the end of the month and to rise each year with your pay, which is what the contribution raises field controls.

Because inflation is subtracted separately, the balance is shown twice: the nominal figure you would see on a statement, and the same figure restated in today money so it can be compared with a spending figure you know.

The nest egg and the withdrawal rate

The balance needed is the annual spending gap divided by the withdrawal rate. At 4%, $36,000 a year of spending on top of Social Security needs $900,000; at 3% the same income needs $1.2m. A lower rate is a safety margin against a bad first decade of returns, not a rule about the future.

The 4% figure comes from historical studies of US market returns. It assumes a roughly balanced portfolio, a long horizon and a willingness to adjust spending when markets fall. Anyone retiring into an expensive market or planning a 40-year retirement should test 3% and 3.5% as well.

How the drawdown is simulated

The withdrawal is taken at the start of each year and grows with inflation, then the remaining balance earns the return for that year. Taking the money first is the cautious order: a poor sequence of returns early in retirement does more damage than the same poor years at the end.

The simulation stops when the balance can no longer cover that year spending, and reports the age at which it happens. It uses a constant return rather than a random one, so the answer is a plan check rather than a probability.

What is not modelled

Taxes on withdrawals, because the rate depends on the mix of traditional, Roth and taxable accounts and on the brackets in force at the time. A traditional 401(k) balance is taxed as ordinary income as it comes out, so the pre-tax balance is not the money you can spend.

Healthcare costs, long-term care, a change of plan, part-time work in retirement and the effect of claiming Social Security later are all outside the model. Treat the answer as the arithmetic of the plan you entered, not a prediction about your life.

Worked examples

Each example below was run through the calculator on this page when the site was built, so the numbers match what you see when you enter the same inputs.

Starting at 35 and saving $600 a month

Current age: 35
Retirement age: 65
Saved so far: $50,000.00
Saved each month: $600.00
Annual return before retirement: 6%
Inflation: 2.5%
Contribution raises: 2%
Spending needed in retirement: $60,000.00
Other income in retirement: $24,000.00
Withdrawal rate: 4%
Plan until age: 90

Balance at 65

$1,048,975.44

$500,091 in today money, after 30 years of saving

Nest egg the spending needs: $900,000.00
Shortfall in today money: $399,908.63
Money still lasts: To age 90
Growth share of the balance: 67.4%

Thirty years of deposits plus the growth on them produces a balance that covers the planned spending with a buffer, which is what the surplus figure is there to show.

A late start at 45 with bigger deposits

Current age: 45
Retirement age: 67
Saved so far: $80,000.00
Saved each month: $1,500.00
Annual return before retirement: 6%
Inflation: 2.5%
Contribution raises: 2%
Spending needed in retirement: $55,000.00
Other income in retirement: $30,000.00
Withdrawal rate: 4%
Plan until age: 92

Balance at 67

$1,268,612.65

$736,892 in today money, after 22 years of saving

Nest egg the spending needs: $625,000.00
Surplus in today money: $111,892.27
Money still lasts: To age 92
Growth share of the balance: 55%

The monthly deposit is two and a half times as large as in the first example and the horizon is seven years shorter. A late start is expensive: the same monthly amount costs far more in total to produce a similar result.

Spending that outruns the balance

Current age: 40
Retirement age: 62
Saved so far: $150,000.00
Saved each month: $800.00
Annual return before retirement: 5%
Inflation: 2.5%
Contribution raises: 1%
Spending needed in retirement: $90,000.00
Other income in retirement: $20,000.00
Withdrawal rate: 4%
Plan until age: 95

Balance at 62

$867,843.84

$504,100 in today money, after 22 years of saving

Nest egg the spending needs: $1,750,000.00
Shortfall in today money: $1,245,900.18
Money runs out at: Age 77
Growth share of the balance: 55.6%

Withdrawals of $70,000 a year that rise with inflation outlast a balance that only funds about half of it. The calculator reports the age at which the money runs out and the size of the monthly deposit that would close the gap.

Frequently asked questions

How much do I need to retire?

Divide the annual spending you need from the portfolio by the withdrawal rate you are willing to use. Needing $40,000 a year from savings at 4% means $1,000,000. The number is driven as much by the spending figure as by the return, and spending is the part most people can still change.

Is 4% still the right withdrawal rate?

It is a reasonable starting point for a 30-year retirement and a balanced portfolio, and probably too generous for a 40-year horizon or for a retiree starting after a long bull market. The withdrawal rate table lets you see the same income funded at 3% to 6% so you can judge the trade-off between the balance you need and the risk you carry.

Why is my projected balance different from other calculators?

Deposit timing, contribution raises, the order of returns and whether inflation is applied inside or outside the projection all move the answer. This calculator adds deposits at the end of each month, grows them with pay, and restates the result in today money, which is the most conservative of the common conventions.

Does the calculator include Social Security?

Only as the other income field, which you control. Entering an assumed benefit reduces the gap the portfolio has to cover, and therefore the nest egg. Benefit amounts depend on your earnings record and the age you claim, so the calculator does not estimate them.

What return should I assume before retirement?

A diversified portfolio has historically returned roughly 7% to 10% a year before inflation and fees, with long stretches above and below that. Running the plan at 5% and 7% and seeing whether both work is more useful than picking one number and believing it.

What happens if I retire earlier or later?

Retiring later helps twice: it adds contributing years and removes withdrawal years. Moving the retirement age by two years in either direction changes the answer more than almost any other input, which is why the age fields are worth experimenting with before changing your saving rate.

Is the money in a traditional 401(k) taxed on the way out?

Yes. A traditional balance is pre-tax money, so withdrawals are taxed as ordinary income, which means the balance shown here is not all spendable. Roth balances come out tax-free, and taxable brokerage accounts pay capital gains rates; the Roth versus traditional calculator compares the three.

Assumptions and sources

The 4% withdrawal rate rule of thumb comes from historical US returns research, beginning with William Bengen (1994) and the Trinity study, which tested constant inflation-adjusted withdrawals against past market data.
This is not investment advice and it is not a retirement plan. Returns are entered by the user, not forecast, and a constant return understates the risk that matters most: a poor sequence of returns in the first years of retirement.
Not modelled: tax on withdrawals, required minimum distributions, healthcare and long-term care costs, pension or annuity income, part-time work, and any change in spending as health and habits change with age.
Inflation is applied as a constant rate. Actual inflation varies year to year, and the basket of goods a household buys differs from the published index, which is why the spending figure is entered in today money.

Last reviewed 2026-09-14. This page is an estimate tool, not financial, tax or legal advice.Read the full disclaimer.

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