Free Online Calculators
Quick, accurate calculators for everyday life — from working out your age and BMI to comparing loan repayments and percentages. Every calculator gives instant results with a clear explanation of the formula used.
Each calculator below explains the formula it uses, so you can understand exactly how your result was produced — not just see a number.
How to Choose the Right Calculator
Our calculators are grouped by what they help you decide. For health and personal tracking, Age Calculator and BMI Calculator give quick, formula-transparent results. For money decisions, Loan / EMI Calculator estimates monthly repayments and total interest before you commit to a loan, Tip Calculator splits a bill fairly among a group, and Discount Calculator works out the real price and savings on a sale item.
For students, GPA Calculator turns a list of grades and credit hours into a weighted average, while Percentage Calculator and Date Difference Calculator handle the everyday maths that comes up in coursework, planning and scheduling. If you need general unit conversions rather than a specific calculation, Unit Converter and Temperature Converter cover length, weight and temperature in one place.
All Calculators
Common Use Cases
- Comparing loan offers — Enter the same loan amount and term at different interest rates to see how much extra you'd pay in total interest before choosing a lender.
- Tracking BMI over time — Recalculate BMI after a change in weight or height units to keep a consistent personal health record, alongside a doctor's guidance.
- Splitting a restaurant bill — Calculate a fair tip and divide the total, including tip, evenly across a group of diners.
- Calculating a semester GPA — Enter each course's grade and credit hours to get a weighted GPA before final grades are officially posted.
Common Mistakes to Avoid
- Treating BMI as a complete health measure. BMI is a simple ratio of weight to height and doesn't account for muscle mass, bone density, age or body composition. Use it as one general reference point, not a diagnosis, and speak with a healthcare professional for personalised advice.
- Forgetting to match units before converting. When switching between metric and imperial calculators, double check that height, weight or distance are entered in the unit the calculator expects — mixing units silently produces a wrong result.
- Ignoring loan fees outside the calculator. A loan calculator estimates principal and interest based on the numbers you enter, but real loans often include origination fees, insurance or early repayment penalties that aren't part of a basic EMI formula. Check your lender's full terms separately.
Frequently Asked Questions
Are these calculators accurate enough for financial or medical decisions?
They use standard, well-established formulas and are accurate for those formulas. However, they're intended as quick reference tools, not a substitute for advice from a qualified financial advisor or healthcare professional — see our Disclaimer for details.
Do I need to create an account to save my results?
No. All calculators work without an account. Results aren't saved between visits, so note down or screenshot any result you want to keep.
Why do calculators show the formula used?
We show the underlying formula so you can understand exactly how a result was produced, verify it independently, or apply the same formula manually if needed.
Can I use these calculators on mobile?
Yes, every calculator is built to work on phones and tablets as well as desktop browsers.