A retirement calculator projects whether your current savings rate is on track to fund your retirement at a chosen age. The two big inputs are your target annual spending and your expected real return.
Quick answer. A retirement calculator projects whether your current savings rate is on track to fund your retirement at a chosen age. The two big inputs are your target annual spending and your expected real return.
Interactive calculator
Retirement nest egg calculator
Project savings to and through retirement using the 4% rule.
Projected balance at retirement-
Nest egg needed (25x rule)-
Surplus or shortfall-
Safe annual withdrawal at 4%-
How is this calculated?
Nest egg target uses the Trinity Study 4% rule: required savings = 25 x annual income needed. Projection uses monthly compounding.
About this tool
The retirement calculator projects whether your current savings rate, balance, and expected return put you on track to fund your retirement at a chosen age. The shorthand answer comes from the Trinity Study: a portfolio equal to 25 times your annual spending supports a 4 percent inflation indexed withdrawal for 30 years with historical success above 95 percent.
Real returns (after inflation) drive the number, not nominal returns. A 7 percent nominal return at 3 percent inflation is a 4 percent real return, which doubles a portfolio's purchasing power every 18 years, not the 10 years a naive 7 percent compounding would suggest. Run every projection in real dollars to keep the answer comparable to today's spending.
Annual spending = expected retirement spending in today's dollars, not pre tax salary.
25 = the inverse of the 4 percent safe withdrawal rate; use 33 for a 3 percent rule, 30 for 3.33 percent.
B0 = current investable assets earmarked for retirement.
PMT = annual contributions (employee plus employer match plus IRA, HSA, taxable savings).
r = real expected return; 5 percent is a reasonable base case, 4 percent for safety, 6 percent if you want optimism with a buffer.
n = years from now until retirement.
Worked example
A 32 year old in 2026 wants to retire at 65 with 60,000 USD per year of spending in today's dollars. Current balance is 200,000 USD across 401(k) and IRA. Annual contributions are 30,000 USD (including match). Real return assumption is 5 percent:
Annual retirement spending: 60,000 USD in today's dollars.
Required nest egg (25x): 60,000 x 25 = 1,500,000 USD in today's dollars.
Years until retirement: 65 - 32 = 33 years.
Growth of current balance: 200,000 x (1.05)^33 = 991,038 USD.
Growth of contribution stream: 30,000 x ((1.05^33 - 1) / 0.05) = 2,343,225 USD.
Projected balance at 65: 991,038 + 2,343,225 = 3,334,263 USD (in today's dollars).
Surplus over target: 3,334,263 - 1,500,000 = 1,834,263 USD.
Safe annual withdrawal at 4 percent: 3,334,263 x 0.04 = 133,370 USD per year.
Result: The household is on track for roughly 133,370 USD of safe annual retirement income, more than double the 60,000 USD target. This buys the option to retire 8 to 10 years earlier, cut savings to optimize for current lifestyle, or build in extra margin against sequence of returns risk.
Retirement target by spending level (4 percent rule)
Annual spending
Target portfolio (25x)
3.5 percent rule (28.6x)
3 percent rule (33x)
30,000 USD
750,000 USD
857,000 USD
990,000 USD
50,000 USD
1,250,000 USD
1,429,000 USD
1,650,000 USD
60,000 USD
1,500,000 USD
1,714,000 USD
1,980,000 USD
80,000 USD
2,000,000 USD
2,286,000 USD
2,640,000 USD
100,000 USD
2,500,000 USD
2,857,000 USD
3,300,000 USD
150,000 USD
3,750,000 USD
4,286,000 USD
4,950,000 USD
Common mistakes
Mixing nominal and real numbers. Either use real returns and today's dollar spending throughout, or inflate everything forward and use nominal returns. Crossing the two double counts inflation.
Using gross income as the target. A pre tax 100,000 USD salary often turns into 50,000 to 70,000 USD of actual spending after payroll tax, savings, and mortgage payoff in retirement. Plan on actual spending, not income.
Ignoring healthcare before Medicare. Early retirees in the US face 1,200 to 2,000 USD per month per couple on ACA marketplace plans before subsidies; budget this separately.
Assuming you will keep working part time. The plan should survive without it. Earned income in retirement is a bonus, not a load bearing assumption.
Forgetting taxes on Traditional withdrawals. A 1,500,000 USD Traditional IRA is roughly 1,200,000 USD after a 20 percent effective tax in retirement; a Roth of the same size is the full 1,500,000 USD spendable.
Single rate forever. Many planners drop the equity allocation 1 percentage point per year between age 55 and 70, which reduces the expected real return from 5 percent toward 3 to 4 percent. Build the glide path into the projection.
For a 30 year horizon it still has roughly a 95 percent historical success rate using US stock and bond returns from Bengen (1994) and the Trinity Study (1998). For a 40 to 60 year early retirement, drop the rate to 3.25 to 3.5 percent for similar safety. Morningstar 2025 research suggests 3.7 percent for a balanced portfolio over 30 years given today's valuation and bond yields.
What real return should I assume?+
5 percent real is defensible for a stock heavy long horizon plan. 7 percent nominal minus 3 percent inflation gives 3.88 percent real, the historical US stock return. Use 4 percent real for margin of safety, 5 percent for base case, and never use 7 percent or higher real for planning.
Should I count Social Security?+
Most planners under age 50 leave Social Security out as a margin of safety against benefit cuts. If you are within 10 years of claiming, model it at 80 percent of the currently scheduled benefit, which is the level the Social Security Trust Fund Trustees project after the OASI fund is depleted around 2033 unless Congress acts.
How does inflation affect my retirement target?+
If you compute the nest egg in real (inflation adjusted) dollars and use a real return rate, the answer is already inflation neutral. If you use nominal returns, you must inflate the target spending forward and inflate every annual withdrawal during retirement to keep purchasing power constant. The 4 percent rule assumes inflation indexed withdrawals.
Sources
Bengen, William P. (1994) Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning.
Cooley, Hubbard and Walz (1998) Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable, the Trinity Study.
Morningstar (2025) The State of Retirement Income, updated safe withdrawal rate analysis.
Social Security Trustees Report (2024) on OASI trust fund depletion projection.
