Calculators
Calculators cover everyday math and finance: percentages, discounts, tips, interest, loans, BMI, age, dates, time, profit margins, ROI and more. Every result is computed instantly in your browser with clear formulas.
All Calculators
Percentage Calculator Calculate percentages, increases, decreases and percentage difference. Use Tool → Percentage Change Calculator Calculate the percentage increase or decrease between two values. Use Tool → Discount Calculator Calculate the final price after a percentage discount. Use Tool → Tip Calculator Calculate tip amounts and split the bill among people. Use Tool → BMI Calculator Calculate your Body Mass Index from weight and height. Use Tool → Age Calculator Calculate your exact age in years, months, weeks and days. Use Tool → Simple Interest Calculator Calculate simple interest on a principal over time. Use Tool → Compound Interest Calculator Calculate compound interest with configurable compounding frequency. Use Tool → Loan Calculator Calculate monthly loan payments and total interest. Use Tool → Mortgage Calculator Estimate monthly mortgage payments and total interest. Use Tool → Date Difference Calculator Calculate the number of days, weeks, months and years between two dates. Use Tool → Time Duration Calculator Calculate the duration between two times of day. Use Tool → Profit Margin Calculator Calculate profit and profit margin from revenue and cost. Use Tool → ROI Calculator Calculate return on investment from invested and returned amounts. Use Tool → GST/Tax Calculator Add or remove GST/tax from a price. Use Tool → Average Calculator Calculate the mean, sum, minimum and maximum of a set of numbers. Use Tool → Roman Numeral Converter Convert numbers to Roman numerals and back. Use Tool → Length Converter Convert length between meters, feet, inches, miles and more. Use Tool → Weight Converter Convert weight between kilograms, pounds, ounces and more. Use Tool → Temperature Converter Convert between Celsius, Fahrenheit and Kelvin. Use Tool → Area Converter Convert area between square meters, hectares, acres and more. Use Tool → Volume Converter Convert volume between liters, gallons, cups and more. Use Tool → Speed Converter Convert speed between km/h, mph, m/s and knots. Use Tool → Data Storage Converter Convert between bytes, KB, MB, GB and TB. Use Tool → Time Converter Convert time between seconds, minutes, hours and days. Use Tool →
Related Articles
Percentage Calculator – Complete Guide & Free Online Tool A percentage calculator solves common percentage problems: what is X% of Y, X is what percent of Y, increase or decrease by a percentage, and percentage difference — all with clear formulas. Free online tool included. Read guide → Percentage Change Calculator – Complete Guide & Free Online Tool A percentage change calculator measures how much a value increased or decreased as a percentage of its original value. Free online tool included. Read guide → Discount Calculator – Complete Guide & Free Online Tool A discount calculator tells you how much you save and the final price after applying a percentage discount to an item. Free online tool included. Read guide → Tip Calculator – Complete Guide & Free Online Tool A tip calculator computes the tip and total, and can split the amount evenly among any number of people. Free online tool included. Read guide → BMI Calculator – Complete Guide & Free Online Tool A BMI calculator computes your Body Mass Index from your weight and height and places it into a standard category (underweight, normal, overweight, obese). Free online tool included. Read guide → Age Calculator – Complete Guide & Free Online Tool An age calculator computes your exact age from your date of birth in years, months, weeks and days. Free online tool included. Read guide → Simple Interest Calculator – Complete Guide & Free Online Tool A simple interest calculator computes interest using the formula principal × rate × time, without compounding. Free online tool included. Read guide → Compound Interest Calculator – Complete Guide & Free Online Tool A compound interest calculator projects how an investment grows when interest is reinvested, with options for how often it compounds. Free online tool included. Read guide → Loan Calculator – Complete Guide & Free Online Tool A loan calculator estimates your monthly payment, total paid and total interest for a fixed-rate loan. Free online tool included. Read guide → Mortgage Calculator – Complete Guide & Free Online Tool A mortgage calculator estimates your monthly payment, total interest and total cost for a home loan. Free online tool included. Read guide → Date Difference Calculator – Complete Guide & Free Online Tool A date difference calculator counts the days, weeks, months and years between two dates. Free online tool included. Read guide → Time Duration Calculator – Complete Guide & Free Online Tool A time duration calculator finds the hours, minutes and seconds between a start and end time (24-hour HH:MM format). Free online tool included. Read guide → Profit Margin Calculator – Complete Guide & Free Online Tool A profit margin calculator computes your profit and margin percentage from revenue and cost: margin = profit / revenue × 100. Free online tool included. Read guide → ROI Calculator – Complete Guide & Free Online Tool An ROI calculator measures the return on an investment: ROI = (returned − invested) / invested × 100. Free online tool included. Read guide → GST/Tax Calculator – Complete Guide & Free Online Tool A GST/tax calculator adds tax to a price or extracts tax from a tax-inclusive price, showing the base amount, tax and total. Free online tool included. Read guide → Average Calculator – Complete Guide & Free Online Tool An average calculator computes the arithmetic mean of your numbers, along with the sum, count, minimum and maximum. Free online tool included. Read guide → Roman Numeral Converter – Complete Guide & Free Online Tool A Roman numeral converter translates numbers (1–3999) into Roman numerals like XIV, and converts Roman numerals back to numbers. Free online tool included. Read guide → Simple Interest vs Compound Interest Understand the difference between simple and compound interest and how each grows money. Read guide → How Percentage Calculations Work Percentages appear everywhere. Learn the core formulas and common mistakes. Read guide →
Frequently Asked Questions
Are these calculators accurate?
Yes. They use standard mathematical formulas and are deterministic — the same input always gives the same output.
Are financial calculators a substitute for advice?
No. They are educational tools and do not constitute financial, tax or legal advice.
Do calculators store my inputs?
No. All calculations happen locally and nothing is stored.