How finfire works

Last reviewed: 9 October 2026

finfire is two retirement calculators for one financial life. Phase 1 · Accumulate follows your investing month by month to the year you stop working. Phase 2 · Burndown follows your savings month by month after that, through an emergency fund and three buckets, with tax on what you redeem, to the year your spendable savings run out. This page sets out the rules both follow, in the order they follow them, and works through each one’s sample plan.

Phase 2 · Burndown: how long your savings last

Phase 2 takes your savings, your monthly spending and the years you plan for, and follows them month by month for up to 120 years.

The rules, in order

1. At the start your savings are split: the emergency fund first, then Bucket 1, then Bucket 2, each given its months of your first year’s monthly spending; Bucket 3 takes whatever is left. Savings too small for all of that fill the buckets in the same order, and the later ones get less.
2. Each month, the month’s spending is taken first: from Bucket 1, and when it runs dry, from Bucket 2, then Bucket 3. Then every bucket, the emergency fund included, grows for the month at the return of its own asset mix, compounded so that twelve months give exactly that return a year.
3. Your monthly spending stays the same through each year and rises with inflation from one year to the next.
4. Enough is redeemed to leave your spending after tax. The tax is on the part of each redemption that is gain, on an average-cost basis, at the rate of the bucket’s asset mix. With Tax slabs (Pro) the year’s gains are added up instead, and the year’s tax is paid at the year end, before the top-ups.
5. At each year end, Bucket 2 tops Bucket 1 back up to its months of the next year’s spending, and if Bucket 2 runs short, Bucket 3 pays the rest. Then Bucket 3 tops Bucket 2 back up to its months, in good years and bad.
6. The emergency fund is never spent. Your spendable savings run out in the first year whose spending Buckets 1, 2 and 3 cannot pay in full; if that is after the years you plan for, the answer says they last all those years, and when, within 120 years, they would run out.
7. Every figure is worked out in full and rounded only where it is shown.

Each part of Phase 2, in the words its own page uses:

What it does

Cash after tax

Takes the tax off every redemption, gains your savings already hold included, to show the cash you actually take home.

Unrealised Gains

Taxes the gains your savings already hold: every bucket starts with the share you give as gain not yet taxed, and pays tax on it as it is redeemed.

Tax slabs

Switch from flat rates to a yearly tax bill on the gains you realise each year: Indian slabs (the rebate, the yearly exemption on equity gains, which foreign shares do not get, surcharge and cess) or US federal brackets (the standard deduction, the 0/15/20% long-term rates, the 3.8% investment income tax). You can edit every figure, and losses are set against gains and carried forward. Other taxable income comes first; only the extra tax your gains add is charged.

Investing abroad

Taxes Equity abroad’s dividends every month, as the India–US tax treaty, India’s credit for the US tax or the fund itself say; with Tax slabs, its gains pay 12.5% with no yearly exemption.

What would it take?

Works back from the years you plan for: the most you can spend a month, or the least savings you need.

Bucket 3 asset mix glide path

Moves Bucket 3, step by step, to a safer mix by the end of the plan.

Market slump

Shows what a market slump in your first years would do to your plan.

Lumpy Cash Flows

Adds large sums of money in or out, once or every year: part-time work, a pension, a house sale, school fees. Money in lands in Bucket 3; money out is taken from Bucket 1, then Bucket 2, then Bucket 3, and taxed as it is redeemed.

Simulated markets

Runs your plan through 2,000 simulated markets, each year's return drawn at random around the one you typed for each investment. It says how often your savings last the years you plan for, and by when your spendable savings run out in 1 in 10, half and 9 in 10 of them. The answer, the table and What would it take? stay those of your plan with steady returns.

Saved plans

Save named plans in your own browser and reopen any of them later; export them to a file to keep a copy or move them to another browser.

Compare

Pin a plan, then change anything: a table under the answer and a dashed line on the chart show how the year your spendable savings run out, your savings at the end and the total tax change.

How it works

Spending and top-ups

Your monthly spending (at least ₹50,000) comes out of Bucket 1. At each year end, Bucket 2 tops up Bucket 1, then Bucket 3 tops up Bucket 2.

Emergency fund

Filled at the start and kept aside. It is never spent, so there is less to spend, and your spendable savings can run out sooner.

Inflation and withdrawal rates

Your monthly spending, and the sizes the buckets are topped up to, rise with inflation. The first year’s withdrawal rate is shown two ways: against all your savings, and against your savings without the emergency fund.

Tax and assumptions

Taxes

Tax is charged when you redeem, on an average-cost basis, and, with Investing abroad (Pro), on Equity abroad’s dividends, every month. Every chart and balance shown is before the tax on what you redeem.

Simplifications

Rebalancing within a single bucket, and the shifts of the Bucket 3 asset mix glide path, are modelled tax-free. Equity abroad moves with your Indian equity in a market slump and in simulated markets; real markets, and the rupee, do not always move together.

The sample, worked through

The sample starts with ₹2.97 Cr of savings and spends ₹1,00,000 a month in the first year, rising 7% a year with prices, over 40 years. Your savings, ₹2.97 Cr, are split at the start: the emergency fund first, then Bucket 1, then Bucket 2. Bucket 3 takes whatever is left. The emergency fund gets ₹12,00,000, Bucket 1 ₹18,00,000, Bucket 2 ₹48,00,000 and Bucket 3 ₹2,19,19,461. That is a withdrawal rate of 4.04% in the first year: ₹12.00 L a year comes out of ₹2.97 Cr of savings. Leaving out the emergency fund, you spend from ₹2.85 Cr: that is 4.21%, or 23.8×. In year 2, spending is ₹1,07,000 a month. Bucket 3 is empty by year 20, and Bucket 2 by year 23. “Your spendable savings run out in year 25.” By then Buckets 1, 2 and 3 are empty, with spending at ₹5.07 L a month. The emergency fund still holds ₹40.64 L, which is kept aside and never counted as money to spend.

Phase 1 · Accumulate: what your savings grow to

Phase 1 takes what you have invested today, what you invest each month and the years until you stop working, and follows them month by month, paying your life goals along the way.

Each part of Phase 1, in the words its own page uses:

How it works

Growth

Your investments grow every month at the return you set, compounded so that twelve months give exactly that return a year. Returns are assumed steady every year; real markets are not.

Investing

Each month’s investment goes in at the start of the month and grows with the rest from then on. It stays the same amount every month until you stop working, unless you set a yearly raise or changes along the way (Pro): a yearly raise lifts it at the start of each year, a new amount replaces it from its year, a pause stops it for a while and picks up where the yearly raise had reached, and a lump sum goes in at the start of its year, before that year’s goals. With Stop investing (Pro), nothing goes in after the year you set, lump sums and changes included, and your savings grow on their own until you stop working.

Equity and debt (Pro)

Instead of one return for everything, each part grows at its own return; at the start of each year everything is rebalanced to that year’s equity share, which can glide in equal steps to a smaller share by your last working year.

Investing abroad (Pro)

Part of your equity (or of your savings, with one return) is held in a fund abroad, kept at that share as everything is rebalanced at the start of each year; today’s investments are taken to hold it already. Each month a twelfth of a year’s dividends is paid on what is held abroad, and the tax on them leaves your savings, whether the month grows or not. A fund listed in the US pays them to you: the US keeps 25% (with a W-8BEN), India taxes them at your rate and credits the US tax up to its own, and what is left goes back in as money you put in. A fund listed in Ireland that keeps its dividends pays 15% inside the fund, and the rest stays in it as growth. Your tax on returns does not apply to what is held abroad. The US does not tax your gains; India taxes them when you sell (12.5% after 24 months), and they go to Phase 2 with the rest of your gain; what you hold abroad goes across as Phase 2’s Equity abroad, whose dividends it taxes every month. What you send abroad each year, your share of each month’s investing and whatever rebalancing moves there, is checked against the LRS limit, each plan year taken as one financial year (April to March) and the rupee falling as you set; the TCS on it is shown, not taken off, as it counts towards your income tax. Rules as at October 2026.

Goals

A goal’s cost is typed in today’s money and rises with inflation to the year it falls in; it is paid at the start of that year, before that year’s investing. A goal larger than what you have takes everything there is, and the part not covered is shown in red; investing carries on after it. A goal in or after your first year without work is left to Phase 2. With Pro a goal can have its own inflation and recur every year for a number of years; the years after you stop working go to Phase 2 as one cash flow, rising at that goal’s own inflation.

Today’s money

Each year’s figures are divided by inflation up to that year, so they read in what money buys today. A balance at the end of a year is counted as money of the next year, which is when it is there to spend: at the end of your last working year it is measured against the prices of your first year without work.

Gains to Phase 2 (Pro)

The page keeps track of the money in your savings that has not grown: what you have invested today, less any gain already in it, each month’s investing and each lump sum as it goes in, and the dividends a fund listed in the US pays you, after tax, as they go back in. A goal takes its share of that money as it is paid. The rest of your savings is gain not yet taxed, growth after any tax on returns included. Its share, to a whole percent, goes across to Phase 2’s Unrealised Gains, and the savings Phase 2 needs, and what Phase 2 says of your savings, are worked out with it.

Income after you stop (Pro)

Money from part-time work, a pension or rent after you stop working full-time, typed a month in today’s money, rises with inflation and goes across to Phase 2 for the years you give it, as money coming in at the start of each year, as Phase 2’s cash flows do; up to three incomes, each with its own years. An income with no first year starts the year after you stop working, and moves with it; its years before you stop are left out. In Phase 2 each lands in Bucket 3, and the buckets stay sized on your whole spending, which errs on the side of caution. The savings Phase 2 needs, What would it take? and what Phase 2 says of your savings are all worked out with it, so with an income that starts as you stop, the earliest year you can stop working is the earliest you can stop working full-time.

What would it take? (Pro)

Each works back from the target, keeping everything else as it is: the least monthly investing that reaches it, rounded up to a whole step, with any yearly raise and changes applied to it as they are now; and the earliest year you can stop working that reaches it, trying each year in turn, since each year moves the target. When your plan falls short, the answer says what either would take; when it has some to spare, how much sooner you could stop. Its switch finds the earliest year you could stop investing (Coast FIRE): each year from today is tried in turn, nothing going in after it, until your savings, growing on their own, reach their target when you stop working. Each year changes how much of your savings is growth, and with it the target, so each year is measured against its own.

Market slump (Pro)

A slump in your last working years: its return takes the place of your return, or of equity’s when you split between equity and debt. What it would leave is shown beside your plan, on the chart and under the answer; your plan, its target and what goes to Phase 2 stay as they are.

Simulated markets (Pro)

Your plan run through 2,000 simulated markets, the same 2,000 for every plan. Each year’s return is drawn around the one you typed, which is the middle of its spread, and strays from it as far as the market volatility says: the spread of a year’s growth, measured in logs, as market volatility usually is. Equity and debt are drawn separately, what you hold abroad with equity, and inflation stays as you typed it; goals, changes to your investing, the glide and the tax on returns all run as in your plan. The answer says what 9 in 10, half and 1 in 10 of the markets end with at least, and how many reach your plan’s target and pay every goal in full; the chart shades where 8 in 10 of them are each year, and dots the middle one. Your plan, its target and what goes to Phase 2 stay as they are.

Saved plans (Pro)

Save named plans in your own browser and reopen any of them later; export them to a file to keep a copy or move them to another browser.

Compare (Pro)

Pin a plan, then change anything: a table under the answer and a dashed line on the chart show how the year you stop, your savings and their target, and what goes in and grows, change.

Before tax

Every figure is before any tax on your returns, unless you set a tax on returns (Pro): an average cost of tax, not a worked-out tax bill. Each month that grows keeps the rest of its growth; a month that loses pays no tax. With Investing abroad (Pro), the tax on dividends abroad is worked out from the rules instead, and paid every month, whether it grows or not.

The sample, worked through

The sample has ₹10,00,000 invested today and puts in ₹25,000 at the start of every month for 25 years, growing 8% a year before tax, while prices rise 7% a year. In year 1, ₹3,00,000 goes in, and the savings reach ₹13,92,847 by the year end, ₹13,01,726 in today’s money. “After 25 years you will have ₹2.97 Cr — ₹54.76 L in today’s money.” That is ₹47.41 L of money put in — ₹10.00 L invested today and ₹25,000 a month for 25 years — and ₹7.35 L of growth, in today’s money.

What the samples assume

Phase 2’s sample opens with these figures, and every one of them can be changed. Each return is a year’s, before tax; in simulated markets it is the middle of each year’s spread.

Phase 1’s sample grows 8% a year before tax, with one return for all its savings. Prices rise 7% a year in both.

From one calculator to the other

With Pro, Phase 1 carries your plan into Phase 2: your savings when you stop working, your monthly spending then, your inflation, the share of your savings that is gain not yet taxed, your goals after you stop and your income after you stop.

Strict Data Privacy

We keep none of your financial figures. The figures you type go to our server for calculation purposes, and are then thrown away at once. Only your email address and account type (Free or Pro) are saved. There are no passwords, no third-party scripts, analytics, trackers, tag managers or outside fonts. Saved plans stay in your own browser, never on our servers.

Your goals’ names never leave your browser: the server is sent only the year of each goal and what it costs.

Read next

• The three-bucket retirement strategy
• Sequence of returns risk
• How long will my retirement savings last?
• Is a 4% withdrawal rate safe in India?