Free online calculators: the complete guide
Most everyday maths falls into a handful of shapes: a percentage, a loan repayment, a bit of interest, a discount, a date gap. The hard part is usually remembering the right formula, not the arithmetic. A focused calculator does the formula for you, so you can go straight to the answer.
This guide is a map of the free online calculators and which one to reach for. Each is a single-purpose tool that runs instantly in your browser — no sign-up, no installs — so you pick the one that matches your question and read off the result.
Money and loans
- EMI calculator — your fixed monthly loan installment from the amount, rate and tenure. The formula is explained in how to calculate EMI.
- Loan calculator — total repayment, total interest and the cost of borrowing over the full term.
- Compound interest and simple interest — how savings or debt grow, with or without interest-on-interest.
- Investment and savings calculators — project a balance forward from regular contributions.
Shopping, tax and pay
- Discount — the sale price and how much you save from a percentage off.
- VAT — add or remove VAT to move between net and gross prices.
- Salary — break a wage down or up across hourly, monthly and yearly.
- Profit & loss — margin and profit from cost and selling price.
Everyday maths
- Percentage — percent of a number, one number as a percent of another, and percentage change. See how to calculate percentages.
- Average and ratio calculators for quick summaries and proportions.
- Basic calculator for straightforward arithmetic when no special formula is needed.
Dates, age and school
- Age calculator — exact age in years, months and days; see how to calculate your age.
- Date difference — the number of days between two dates, covered in counting days between dates.
- GPA, CGPA and grade calculators for students tracking academic results.
How to get an accurate answer
- Match the tool to the question. An EMI is not the same as total interest; a discount is not the same as VAT. The named tool applies the right formula.
- Check your units. Enter the rate as an annual figure where asked, and the tenure in the unit the tool expects.
- Read every output field. Finance tools often show more than one number — for a loan, the monthly payment and the total cost tell different parts of the story.
Frequently asked questions
Are these calculators free?
Yes. Every tool on the calculators page is free and runs in your browser with no account required.
Is my data sent anywhere?
The calculations happen in your browser, so the numbers you type are used to work out the answer and are not the point of the tool — you get the result instantly on the page.
Which calculator should I use for a loan?
Use the EMI calculator for the monthly payment and the loan calculator for the total interest and cost over the whole term.
Browse all calculators
Open the calculators page to see the full set, or jump straight to the percentage, EMI or age calculator if you already know what you need.
