Free tools

Financial calculators

Four questions worth doing the arithmetic on before you decide anything. No sign-up, no email, no data leaving your browser — and every one of them shows its assumptions rather than hiding them behind a single number.

Retire

FIRE Calculator

Work out the age your savings can take over from your salary. Gives Lean, Regular, Fat and Coast FIRE targets, the corpus each one needs, and a projection against a goal that inflates as you do.

"At what age can I stop working?"

Open the FIRE calculator →

Grow

SIP Calculator

See what a fixed monthly investment becomes, split into what you put in and what compounding added. Handles annual step-ups, an opening lumpsum, and what it is all worth in today's money.

"What will my money become?"

Open the SIP calculator →

Borrow

EMI Calculator

The instalment, the total interest, and a full year-by-year amortisation schedule — plus what paying a little extra each month does to the term and the total.

"What is this loan really costing me?"

Open the EMI calculator →

Decide

Rent vs Buy

A fair fight: your net worth after buying, against your net worth after renting and investing everything you didn't spend on the house. Stamp duty, maintenance and selling costs all counted.

"Should I buy, or keep renting?"

Open Rent vs Buy →

How these work

Built the same way as the app.

Same principle as everything else at Zinfai: your numbers are yours, and a figure that is an estimate should say so.

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Nothing is sent anywhere

Every calculation runs in your browser. There is no request carrying your salary, your rent or your net worth to a server, because there is no server involved.

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Eight currencies

Switch between INR, USD, GBP, EUR, AED, AUD, SGD and CAD. Rupee amounts group in lakh and crore, the way you would actually write them.

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Assumptions on the page

Each calculator states what its model does and what it ignores — tax, fees, sequence risk — so you can judge how much weight the answer deserves.

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Every chart has a table

Behind each chart is the same data as rows and columns, so nothing is locked behind a hover, and the numbers are yours to copy.

The full picture

These take numbers you type. Zinfai takes the real ones.

A calculator is only as good as the figures you remember off the top of your head. The Zinfai desktop app works from your actual position — 40+ asset types across five jurisdictions in their own currencies, bank and broker statements parsed into transactions, live prices, and a FIRE engine that runs on all of it instead of one guessed corpus.

It runs entirely on your own machine, with no cloud account.

Download Zinfai See every feature