Calculators

About Calculators

A calculator that returns a number and nothing else is only half useful. If you are working out a loan repayment, the figure matters, but so does knowing which formula produced it and what happens when one input moves — because the actual question is almost never 'what is the payment' and almost always 'can I afford this, and what changes if the rate goes up'.

The financial calculators here use standard amortisation maths: the EMI and loan tools apply the reducing-balance formula that banks use, where each payment covers the interest accrued that period first and the remainder reduces principal. That is why total interest paid falls sharply when you shorten a term but only modestly when you overpay occasionally, and the schedules these tools produce show that rather than asserting it.

A word on the health calculators. BMI is a population-level statistic being applied to one person, which is a known limitation rather than a controversial opinion — it uses height and weight alone, so it cannot distinguish muscle from fat and systematically misclassifies both athletes and the elderly. It is a useful rough screen and nothing more. Anything that would change a medical decision belongs with a clinician, not a web page.

Calculators — Frequently Asked Questions

How is EMI calculated?

With the standard reducing-balance formula: EMI = P × r × (1+r)^n ÷ ((1+r)^n − 1), where P is the principal, r is the monthly interest rate (annual rate divided by twelve, expressed as a decimal) and n is the number of monthly instalments. Each payment is split between interest on the outstanding balance and principal reduction, with the interest share shrinking over time.

Are these calculators accurate enough to make decisions on?

The arithmetic is exact, but real quotes rarely match it, because lenders add processing fees, insurance, day-count conventions and rounding rules that vary by institution and country. Treat the output as a well-founded estimate for comparing options, and the lender's written offer as the number that actually binds.

Is BMI reliable?

Only as a rough screen. It is a ratio of weight to height squared, so it cannot tell muscle from fat and does not account for age, sex, bone density, or where body fat is distributed — which is why muscular people are routinely classified as overweight and why waist measurement often predicts health risk better. Useful as a starting point, not as a diagnosis.

Do these work offline?

Yes. Every calculator here is JavaScript running in your browser, so once the page has loaded you can disconnect and keep using it. Nothing you enter is transmitted anywhere.