Finance & Investing

FIRE Number Calculator: How Much Corpus Do You Need to Retire Early?

Published July 4, 2026 · 6 min read · apps2help.com

FIRE — Financial Independence, Retire Early — starts with one number: how much you need saved before your investments alone can cover your living expenses, indefinitely. Without a target number, "save more" has no finish line.

This guide explains how to estimate your retirement corpus from your monthly expenses, current age, target retirement age, and inflation.

Quick answer: Enter your monthly expenses, current age, retirement age and expected inflation into the free Apps2Help FIRE Calculator to get your estimated FIRE number instantly.

The Building Blocks of a FIRE Number

Your FIRE number depends on a handful of inputs, each of which meaningfully changes the final target.

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Monthly Expenses

Your baseline cost of living today.

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Current & Target Age

How many years you have to build the corpus.

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Inflation Rate

How expenses grow between now and retirement.

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Withdrawal Rate

The safe percentage you draw down each year.

Step-by-Step: Estimate Your FIRE Number

  1. Open the FIRE Calculator
  2. Enter your current monthly expenses
  3. Enter your current age and target retirement age
  4. Enter your expected annual inflation rate
  5. Click Calculate to see your estimated retirement corpus

Try the FIRE Calculator — Free

Plan your financial independence number privately, right in your browser.

Calculate My FIRE Number →

What Is a Safe Withdrawal Rate?

A safe withdrawal rate is the percentage of your retirement corpus you can draw down each year without running out of money over a long retirement. A commonly cited starting point is around 3-4% annually, though the right number for you depends on your investment mix, expected returns, and how long your retirement needs to last.

Building a Retirement Corpus in India

For an Indian investor, factoring in inflation is especially important, since prices for everyday expenses tend to rise faster in higher-inflation years. Running your numbers with a realistic inflation assumption, rather than today's expenses alone, gives a far more accurate picture of what you'll actually need by the time you retire.

Is This Calculator Financial Advice?

No. The FIRE Calculator is an informational planning tool that estimates a corpus based on the numbers you enter. It does not account for your specific investments, taxes, or risk tolerance, and is not a substitute for advice from a qualified financial professional.

Frequently Asked Questions

What is a FIRE number?+
Your FIRE number is the total corpus you'd need for your investments to sustainably cover your living expenses without relying on active income.
How does inflation affect my retirement corpus?+
Inflation increases your future expenses, so a higher inflation assumption results in a larger required corpus by your target retirement age.
What is a safe withdrawal rate?+
It's the percentage of your corpus you withdraw annually in retirement, commonly estimated around 3-4%, though this varies by individual circumstances.
Is my financial data stored anywhere?+
No, the calculation happens entirely in your browser and your inputs are not transmitted or stored.
Is this tool a substitute for financial advice?+
No, it's for informational purposes only. Consult a qualified financial professional for advice specific to your situation.

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Where the FIRE Number Comes From

The familiar rule of thumb — save twenty-five times your annual spending — is simply the inverse of a 4% withdrawal rate. If you withdraw 4% of a portfolio in the first year and adjust that amount for inflation thereafter, twenty-five times annual spending is the starting balance that produces it. The figure traces back to studies of historical US market returns over thirty-year retirements, most famously the Trinity study of the late 1990s.

It is a useful starting point and a poor stopping point. The research it rests on assumed a specific asset mix, a specific country's market history, a thirty-year horizon and no fees. Retire at forty rather than sixty-five and your horizon is fifty years, not thirty. Invest outside that market and the historical record differs. Pay 1% a year in fund costs and a quarter of your withdrawal rate has gone before you spend anything.

Withdrawal rateMultiple of annual spendingCharacter
5%20×Aggressive; vulnerable to a poor first decade
4%25×The classic benchmark, 30-year horizon
3.5%~29×Common choice for early retirement
3%~33×Conservative; suits very long horizons

Spending, Not Income, Is the Input

The number that drives everything is what you actually spend, not what you earn. Most people underestimate it, because the calculation is usually done from memory rather than records. Twelve months of real bank and card statements will give you a figure; a mental estimate will not. Remember to include the costs that do not arrive monthly — insurance renewals, car maintenance, replacing a laptop, a boiler, a roof — because they arrive regardless.

Two adjustments matter especially for early retirement. Health cover that an employer previously provided becomes a direct cost, and it tends to rise faster than general inflation. And a mortgage that ends in twelve years means your spending is not one flat line but two levels, which a single multiple cannot express.

A useful sanity check: calculate your number from last year's actual spending, then again from your best guess made without looking. The gap between the two is a fair measure of how much you should trust any projection built on the guess.

Sequence Risk: Why Averages Mislead

Two retirees can experience identical average returns over thirty years and end up in completely different positions, purely because of the order in which those returns arrived. Poor returns in the first few years, while you are also withdrawing, sell down units at depressed prices and permanently shrink the base that later recovery works on. The same poor years occurring at the end are largely harmless.

This is the single strongest argument against treating any multiple as a guarantee, and the reason common mitigations exist: holding two or three years of spending in cash or short bonds so you need not sell equities into a slump, keeping some flexibility to trim discretionary spending in a bad year, or maintaining some earned income during the first few years.

Inflation Quietly Doubles the Problem

At 6% inflation, prices double in about twelve years. At 3%, in about twenty-four. Either way, a retirement lasting several decades will see your required spending multiply. Any corpus figure quoted in today's money must be paired with an investment approach capable of growing faster than prices, which is why long-horizon plans usually keep meaningful equity exposure rather than moving entirely to fixed deposits.

Tax, Fees and the Gap Between Gross and Net

The withdrawal you can spend is the amount after tax and after costs. Where your money sits — taxable accounts, tax-deferred retirement accounts, tax-free wrappers — changes the net figure substantially, and the rules differ by country and change over time. A 1% annual expense ratio consumes a quarter of a 4% withdrawal. Moving to lower-cost funds is one of the few levers that improves the outcome without requiring you to save more or accept more risk.

Treat the Number as a Direction, Not a Finish Line

A single figure produced by a calculator is a projection built on assumptions about returns, inflation and spending that nobody can know in advance. Its value is in showing how sensitive the outcome is to each input — try 3.5% instead of 4%, or spending 10% higher, and watch the target move. That sensitivity is the real output.

This article and the calculator are general educational information, not financial advice. Personal circumstances, tax rules and local regulation vary enormously, and a qualified adviser who can see your full position is the right person to consult before making decisions of this size.

Your Figures Stay in Your Browser

The calculator runs locally. Your income, spending and target figures are never uploaded, stored or associated with you, and there is no account to create. Watch the Network tab in developer tools while you calculate, or disconnect from the internet after the page loads — it keeps working.

Frequently Asked Questions

Is the 25x rule reliable?

It is a useful starting point derived from a 4% withdrawal rate and studies of thirty-year retirements in US market history. It was not designed for fifty-year horizons, other markets, or portfolios carrying meaningful fees. Many people planning early retirement use 3% to 3.5% instead, which implies roughly 29 to 33 times annual spending.

Should I base the calculation on my income or my spending?

Spending, and ideally spending measured from twelve months of actual statements rather than memory. Include irregular costs such as insurance renewals, car maintenance and replacing major items, because they arrive whether or not you budgeted for them.

What is sequence risk?

It is the risk that poor returns arrive early in retirement while you are also withdrawing. Selling units at depressed prices permanently shrinks the base that later recovery works on, so two retirees with identical average returns can end up in very different positions depending purely on the order those returns arrived.

How should I account for inflation?

Assume your required spending will multiply over a long retirement - at 6% inflation prices double in about twelve years. Any target expressed in today's money needs an investment approach capable of outgrowing prices, which is why long-horizon plans usually retain meaningful equity exposure.

Do fees really matter that much?

Yes. A 1% annual expense ratio consumes a quarter of a 4% withdrawal before you spend anything. Reducing costs is one of the few levers that improves the outcome without requiring you to save more or take on more risk.

Is this financial advice?

No. This is general educational information and the calculator is a projection tool. Tax rules, market conditions and personal circumstances vary widely, and decisions of this size warrant a qualified adviser who can see your complete position.

Are my figures stored anywhere?

No. The calculator runs entirely in your browser, nothing is uploaded, and there is no account. You can confirm it in the Network tab of developer tools, or by disconnecting from the internet after the page loads.