How Long Will My Money Last Calculator

Start with Current Savings — the total value of all investment accounts you plan to draw from. Set your expected Annual Return as a long-term nominal average (before inflation).

Enter your Monthly Spending Need in today's dollars — the total amount you need each month for living expenses. Set the Inflation Rate to control how spending grows each year. This same rate also inflates your Social Security and other income, keeping everything in consistent nominal dollars.

Add your Social Security benefit (today's dollars) and start age. The calculator inflates SS to the start year and applies annual COLA from there. Add any other income (pension, rental) in Other Monthly Income — also inflated each year.

In Advanced Options, set your Life Expectancy (the longevity score measures against this), choose your Account Type (traditional, Roth, or mixed), and set your effective tax rate. Traditional and mixed account withdrawals are grossed up so your after-tax spending meets your target.

Results update automatically — spending begins at your current age, not one year later.

Current Savings

Total retirement savings across all accounts — 401(k)s, IRAs, brokerage accounts. This is the starting portfolio balance that generates investment returns and funds your withdrawals.

Annual Return

Expected average annual nominal return on your investments. A typical long-term stock/bond blend returns 5–7% nominal. Using a conservative estimate gives a more resilient plan.

Monthly Spending Need

Your total monthly living expenses in today's dollars. This is the amount you need after taxes — if your account is traditional, the calculator automatically grosses up withdrawals to cover taxes. Spending increases each year by the inflation rate. For help estimating this, use the retirement spending calculator or create a retirement budget.

Inflation Rate

This single rate drives three things simultaneously:

1. Spending growth: Your monthly spending increases by this rate each year
2. Social Security COLA: Your SS benefit inflates from today's dollars to start age, then receives annual increases
3. Other income growth: Pension and other income inflate each year

This means all cash flows grow consistently — spending, income, and costs stay in proper proportion over time.

Social Security & Start Age

Enter your estimated monthly benefit in today's dollars. The calculator inflates it to your start age, then applies annual COLA during retirement. Every dollar from Social Security is a dollar you don't withdraw from your portfolio. See the best age to take Social Security calculator to optimize your claiming decision.

Other Monthly Income

Pension, rental income, part-time work, or annuity payments — in today's dollars. Inflated each year at your inflation rate. This income reduces portfolio withdrawals.

Life Expectancy

Your target age for your money to last. The longevity score measures what percentage of this target is funded. Default is 95 — adjust based on your health and family history. Planning to age 95–100 is appropriate for couples, since there's a high probability at least one spouse reaches that age.

Account Type & Tax Rate

• Traditional (pre-tax): Withdrawals are taxed. The calculator grosses up to ensure your after-tax spending meets your target. Example: $3,000/mo spending at 22% tax requires ~$3,846/mo gross withdrawal.
• Roth (after-tax): Withdrawals are tax-free. No gross-up needed.
• Mixed: A blend — the Roth portion is tax-free, the traditional portion is grossed up.

The effective tax rate is your marginal rate on withdrawals. A typical range is 12–24%. Learn more about how 401(k) withdrawals are taxed.

This calculator runs a year-by-year simulation starting at your current age. Unlike many calculators that skip year 0, spending begins in the current year — a 65-year-old's first withdrawal happens at age 65, not 66.

For each year:

1. Inflate spending: Monthly spending × 12 × (1 + inflation)^year
2. Inflate income: Social Security (if started) and other income inflated the same way
3. Calculate net portfolio need: Spending minus income (floored at zero)
4. Gross up for taxes: If traditional or mixed, divide the net need by (1 − tax rate) to get the gross withdrawal
5. Withdraw from portfolio: The lesser of the gross need or remaining balance
6. Apply investment growth: Remaining balance grows at the annual return rate
7. Record: End-of-year balance, withdrawal, tax, income, growth, and today's-dollar balance

The simulation runs until the balance reaches zero or the projection period ends (life expectancy + 10 years).

Bad-Sequence Scenario

The calculator also runs a poor-sequence-of-returns scenario: returns are reduced by 4 percentage points for the first 10 years, then increased by 2 points for remaining years. This models the risk of retiring into a bear market — the same average return over time, but with poor early returns that force you to sell at low prices. This is the most common reason real-world retirees run out of money faster than expected.

Inflation-Adjusted Spending

year_spending = monthly_spending × 12 × (1 + inflation_rate)^year

Inflation-Adjusted Income

ss_income(year) = IF(age >= ss_start_age,
  ss_monthly × 12 × (1 + inflation_rate)^year, 0)

other_income(year) = other_monthly × 12 × (1 + inflation_rate)^year

total_income = ss_income + other_income

Tax Gross-Up

net_need = max(0, year_spending - total_income)

Traditional:  gross_withdrawal = net_need / (1 - tax_rate)
Roth:         gross_withdrawal = net_need
Mixed:        gross_withdrawal = (roth_share × net_need) + (trad_share × net_need / (1 - tax_rate))

tax_paid = gross_withdrawal - net_need

Year-End Balance

balance_after = starting_balance - gross_withdrawal
growth = balance_after × annual_return
ending_balance = max(0, balance_after + growth)

Bad-Sequence Returns

return(year) = IF(year <= 10, annual_return - 4%, annual_return + 2%)

Longevity Score

years_needed = life_expectancy - current_age
score = min(100, years_money_lasts / years_needed × 100)

The 4% rule suggests withdrawing 4% of your initial portfolio in year one, then adjusting for inflation each year. Historically, this has had a high success rate over 30-year periods.

With a $1 million portfolio, the first-year withdrawal is $40,000. If inflation is 3%, the second year is $41,200. This calculator lets you test any spending level and see the exact impact on your depletion age.

Important: the 4% rate is a pre-tax withdrawal rate for balanced portfolios. If your account is traditional, you need to withdraw more than 4% gross to get 4% after taxes. This calculator handles that automatically with the tax gross-up.

For a deeper dive, use the 4% rule retirement withdrawal calculator.

Longevity risk — outliving your savings — is the primary risk this calculator quantifies. The bad-sequence chart adds a second dimension: even if your average return is adequate, poor returns in your first decade of retirement can deplete your portfolio years earlier.

Strategies to manage longevity risk:

1. Delay Social Security: Claiming at 70 instead of 62 increases your monthly benefit by over 75%, creating a larger inflation-adjusted income floor for life.
2. Purchase an annuity: An annuity converts a lump sum into guaranteed lifetime income, covering essential expenses.
3. Use a conservative withdrawal rate: Starting at 3.5% instead of 4% adds significant margin.
4. Maintain growth allocation: A balanced portfolio with some stocks provides the growth needed to sustain 25+ years of withdrawals.
5. Plan for your life expectancy, not the average: A 65-year-old couple has a ~50% chance that at least one spouse lives past 90.

• Depletion Age: The age at which your portfolio balance reaches zero. If shown as "95+", your money outlasts your life expectancy target.
• Longevity Score: What percentage of your target retirement (through life expectancy) is funded. 100 = fully funded.
• Gross Withdrawal Rate: Your first-year gross portfolio withdrawal as a percentage of savings. Includes the tax gross-up for traditional accounts.
• Bad Sequence: Depletion age if poor returns hit your first decade. Compares directly to the base case.
• Base Case vs Bad Sequence chart: Shows both scenarios on one chart. The gap between the lines represents your vulnerability to sequence-of-returns risk.
• Today's $ column: Your portfolio balance in current purchasing power — strips out inflation to show real wealth.
• Sensitivity Analysis: Shows depletion age at different spending levels, color-coded against your life expectancy target.

• Reduce Monthly Spending: The most powerful lever. Even $200/mo less can add years. Use the sensitivity table to see the trade-off.
• Delay Social Security: Higher benefits reduce portfolio withdrawals for life.
• Work Part-Time: Earning income in early retirement lets your portfolio grow longer before heavy withdrawals begin.
• Consider an Annuity: An immediate annuity covers essential expenses with guaranteed income.
• Consider Roth Conversions: Converting traditional to Roth before retirement eliminates future tax gross-up, making each dollar go further.
• Adjust Asset Allocation: A too-conservative portfolio may not generate enough growth. A balanced stock/bond mix often outperforms all-bonds over 20+ year horizons.

1. Ignoring inflation: A $3,000/mo spending plan becomes $5,400/mo in 25 years at 2.5% inflation. This calculator inflates everything automatically.
2. Forgetting taxes on traditional accounts: A $3,000/mo spending need from a traditional 401(k) requires ~$3,850/mo gross at 22% tax. Use the tax gross-up feature.
3. Using a single constant return: Real markets have good and bad decades. The bad-sequence scenario shows what happens when poor returns come first.
4. Planning for average life expectancy: Half of people live longer than average. Plan to age 95+ for safety.
5. Not inflating Social Security: SS benefits receive annual COLA. A $2,000/mo benefit today becomes $2,640/mo in 12 years at 2.5% inflation. This calculator handles that automatically.
6. Ignoring healthcare costs: Healthcare is one of the fastest-growing retirement expenses. Use the retirement healthcare cost calculator to estimate.

Knowing how long your money will last is the foundation of a confident retirement. Use the calculator above to get your baseline, then check the bad-sequence scenario to stress-test your plan. Experiment with spending levels using the sensitivity table.

For a comprehensive plan that includes detailed expenses, taxes, and healthcare costs, try the main retirement calculator. Explore all our retirement calculators and the learning center for guides on tax-efficient withdrawals and retirement budgeting.