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About This Site

Who built this

My name is James. I'm a software developer, and I built Investment-Calculator.com because I kept running into the same problem: every financial calculator I found online was either buried in ads, required a sign-up, or didn't show its work. I wanted tools that were fast, transparent about the math, and didn't come with strings attached.

I'm not a financial advisor or a licensed investment professional. What I do bring is a developer's instinct for accuracy — every calculator on this site uses the standard financial formulas that textbooks and professional tools use, and each page documents those formulas and links to authoritative sources so you can verify the methodology yourself.

What this site is

Investment-Calculator.com is a collection of 8 free financial calculators covering the most common personal finance calculations: compound interest, return on investment, SIP and dollar cost averaging, loan EMI, retirement planning, inflation impact, stock profit and loss, and FIRE number.

Every calculator runs entirely in your browser. Nothing you enter is sent to a server, stored, or tracked. There are no accounts, no paywalls, and no ads. The site exists to give anyone a fast, honest answer to a financial question.

How we ensure accuracy

Each calculator is built on established financial formulas — the same ones used in textbooks, spreadsheets, and professional financial software. The compound interest calculator uses A = P(1 + r/n)nt. The loan EMI calculator uses the standard amortization formula. The retirement planner uses the future value of an annuity. None of these are proprietary or invented — they are well-documented, peer-reviewed methods.

Each calculator page includes a methodology note that names the formula, defines its variables, and links to an authoritative external source — the Federal Reserve, the Bureau of Labor Statistics, the CFPB, the IRS, or the academic research the withdrawal rates are drawn from. If a number doesn't look right, the methodology note is the starting point for checking the math.

If you find an error in a calculation, please get in touch. Getting the numbers right is the whole point.

What this site is not

The results from these calculators are projections based on the inputs you provide and the assumptions built into each formula. They are for planning and educational purposes only.

  • We are not a registered investment advisor and do not provide personalised financial advice.
  • Calculator results do not account for taxes, fees, inflation adjustments (unless explicitly modelled), or individual circumstances.
  • Past market returns used as default inputs are historical averages and do not guarantee future results.
  • Nothing on this site should be taken as a recommendation to buy or sell any security or take any specific financial action.

For decisions involving significant amounts of money, consult a qualified financial advisor or certified financial planner who can account for your full financial picture.

Methodology references

The following external sources inform the default assumptions and formula implementations used across the calculators:

Investment-Calculator.com is an independent site. It is not affiliated with any financial institution, brokerage, or investment product. Results are for informational purposes only and do not constitute financial, tax, or legal advice.