Retirement Calculator
Estimate your retirement corpus from current savings and contributions, the corpus needed to fund inflation-adjusted spending, and any shortfall or surplus — with conservative, base and optimistic scenarios and fully editable assumptions.
Written by the CalcBundle Research & Editorial Team · Reviewed by the Quality Review Team · Transparent formulas · results are estimates, not advice. · Updated
Estimated retirement corpus
Enter ages so that current age < retirement age < life expectancy.
What a retirement calculator does
A retirement calculator answers the most consequential financial question most people ever ask: will I have enough? It does this by comparing two numbers that are easy to feel vaguely anxious about but hard to estimate on your own — how much your savings will grow to by the time you stop working, and how large a pot you will actually need to fund the life you want afterwards. This calculator projects both, subtracts one from the other, and shows the gap as a clear surplus or shortfall, along with the monthly contribution that would close it. That turns retirement from a source of dread into a set of adjustable levers: save more, work a little longer, or trim target spending.
How it works
- Accumulation: current savings plus monthly contributions (with optional annual increases) compounded at your assumed pre-retirement return.
- Requirement: the present value at retirement of your inflation-adjusted spending, net of other income, over your retirement years, at your assumed post-retirement return.
- Gap: estimated corpus minus required corpus, plus the level monthly contribution that would close it.
Why inflation sits at the heart of the plan
The single biggest reason casual retirement estimates go wrong is ignoring inflation. A lifestyle that costs $40,000 a year today might cost well over $70,000 in twenty-five years at 3% inflation, and prices keep rising throughout retirement itself. This calculator enters your spending in today's money and grows it by your inflation assumption, so the target reflects future prices rather than present ones. You can model the inflation piece on its own with the inflation calculator to see just how much difference the rate makes.
Conservative, base and optimistic scenarios
Because returns and inflation are uncertain, a single projection can mislead in either direction. The calculator shows a range — a cautious case, a central case and an optimistic case — so you can plan around a spread of outcomes rather than a single hopeful line. Prudent planning usually aims to be comfortable even in the conservative scenario, treating anything better as a welcome bonus rather than the assumption the whole plan rests on.
Why every assumption is editable
There is no universally correct return, inflation rate or withdrawal rate, so this calculator hides nothing behind fixed constants — your pre-retirement return, post-retirement return and inflation are all visible inputs you can change. See how steady contributions compound in the SIP calculator and compound interest calculator, and once you have a plan, check your overall position today with the net worth calculator.
Frequently asked questions
How much do I need to retire?
It depends on your spending, how long retirement lasts, inflation and the return your savings earn. This calculator estimates the corpus needed to fund your desired inflation-adjusted spending, net of other income, from retirement to life expectancy.
What assumptions does it use?
Every key assumption is a visible, editable input: your pre-retirement return, your return in retirement, and expected inflation. Spending is entered in today's money and grown by inflation to your retirement date.
How does inflation affect retirement?
Inflation raises the cost of your lifestyle every year, both before and during retirement. The calculator grows your desired spending by inflation so the required corpus reflects future prices, not today's.
Why are the results only estimates?
Real returns, inflation, contributions, spending and how long you live are all uncertain. The conservative, base and optimistic scenarios show a range, but no projection is a guarantee.
What is the 4% rule?
The 4% rule is a well-known rule of thumb suggesting you can withdraw about 4% of your retirement savings in the first year, then adjust that amount for inflation each year, with a reasonable chance the money lasts around 30 years. It is a useful starting point rather than a guarantee — it came from historical data, assumes a particular mix of stocks and bonds, and can be too high or too low depending on markets, fees and how long your retirement lasts. This calculator lets you set your own return and spending instead of relying on a single rule.
How does starting early change how much I need to save?
Enormously, because of compounding. Money invested in your twenties has decades to grow, so each early dollar does far more work than a dollar added near retirement. Starting ten years sooner can roughly halve the monthly contribution needed to reach the same corpus. If you are starting later, the levers are saving more, working a little longer, or adjusting target spending — the calculator shows how each one moves the gap.
Should I include Social Security or a pension?
Yes — enter them as other retirement income. Any guaranteed income reduces the amount your own savings must cover, which lowers the corpus you need to build. Because the calculator sizes the required corpus net of other income, including a pension or state benefit gives a much more realistic target than ignoring it.
Related calculators
Compound Interest
Project growth from an initial amount, rate, compounding and regular contributions.
SIP
Estimate the future value of regular monthly investments, with step-up.
Inflation
See how inflation changes future prices and purchasing power.
Net Worth
Add up assets and liabilities to find your net worth and ratios.
Sources & methodology
- Formula
- Future Value = PV × (1+r)^n + PMT × [((1+r)^n − 1) ÷ r]; Retirement Need = Annual Expenses × Years in Retirement (inflation-adjusted)
- Reviewed
- September 2026
Primary sources
- IRS Revenue Procedure 2024-61 – 2025 Retirement Contribution LimitsOfficial IRS 2025 contribution limits: $23,500 for 401(k)/403(b), $7,000 for IRA ($8,000 age 50+), and income phase-out ranges for Roth IRA.
- SSA – Retirement BenefitsSocial Security Administration publication on full retirement age, benefit calculation, and the impact of claiming age on monthly benefit.
- Vanguard – How America Saves 2024Annual Vanguard research report on 401(k) savings rates, contribution levels, and retirement preparedness benchmarks by age and income.
Calculation methodology is documented on our methodology page. Reviewed by the CalcBundle Quality Review Team.
Disclaimer. This calculator provides estimates for informational purposes only. Results are based on the information you enter and the assumptions used by the calculator. Actual financial, tax, business valuation, lending, marketplace or investment outcomes may differ. Consider consulting a qualified professional for decisions involving significant amounts of money. Retirement projections are estimates and depend on investment returns, inflation, contributions, spending and longevity assumptions. They are not guaranteed and are not financial advice.