Calculators & Converters
Percentage, finance, marketing, date and unit calculators with clear formulas.
What are online calculators and converters?
Online calculators and converters do everyday maths instantly: percentages, discounts, VAT, loan EMIs, compound interest, profit margins and ad campaign metrics, plus dates, ages, time zones and unit conversions for length, weight, temperature, data and more — each with the formula explained.
| I want to… | Use this tool |
|---|---|
| Work out a percentage or percentage change | Percentage Calculator |
| Calculate a monthly loan payment | Loan EMI Calculator |
| Find CPM, CPC, CTR and ROAS | CPM, CPC, CTR & ROAS Calculator |
| Count days between two dates | Date Difference Calculator |
| Convert kilograms to pounds | Weight Converter (kg, lb, oz) |
Percentage Calculator
Calculate X% of Y, what percent X is of Y, percentage change and increase or decrease by a percentage.
Popular
Discount Calculator
Work out the sale price and savings, including stacked discounts and sales tax.
VAT / GST Calculator
Add or remove VAT, GST or sales tax at any rate and see net, tax and gross amounts.
Loan EMI Calculator
Calculate the monthly payment (EMI), total interest and yearly amortization of any loan or mortgage.
Popular
Compound Interest Calculator
See how savings grow with compound interest and monthly contributions, year by year.
Profit Margin Calculator
Calculate gross margin, markup and profit, or the selling price needed for a target margin.
ROI Calculator
Calculate return on investment and annualised ROI (CAGR) for any investment or campaign.
CPM, CPC, CTR & ROAS Calculator
Calculate advertising metrics — CPM, CTR, CPC, conversion rate, CPA and ROAS — from your campaign numbers.
Popular
Break-Even Calculator
Find how many units you must sell to cover fixed costs, and the revenue needed to break even.
BMI Calculator
Calculate body mass index in metric or imperial units and see the healthy weight range for your height.
Tip Calculator
Calculate the tip and split the bill between people, with optional rounding up.
Average & Statistics Calculator
Calculate the mean, median, mode, range, standard deviation, variance and quartiles of a list of numbers.
Random Number Generator
Generate secure random numbers in any range — one or thousands, unique or sorted.
Salary to Hourly Calculator
Convert pay between hourly, daily, weekly, monthly and yearly salary.
Roman Numeral Converter
Convert numbers to Roman numerals (1–3999) and Roman numerals back to numbers.
Number to Words Converter
Write numbers in words for cheques and invoices, including currency amounts and the lakh/crore system.
Age Calculator
Calculate exact age in years, months and days, total days and weeks, and days until the next birthday.
Popular
Date Difference Calculator
Count the days, weeks, months and working days between two dates.
Add or Subtract Days from a Date
Add or subtract days, business days, weeks, months or years from any date.
Time Zone Converter
Convert a date and time between time zones worldwide, with daylight saving applied automatically.
Temperature Converter (°C, °F, K)
Convert temperatures between Celsius, Fahrenheit, Kelvin and Rankine.
Length Converter
Convert length and distance: mm, cm, m, km, inches, feet, yards, miles and nautical miles.
Weight Converter (kg, lb, oz)
Convert weight and mass: mg, g, kg, tonnes, ounces, pounds, stone and tons.
Area Converter
Convert area: square metres, square feet, acres, hectares, square miles and more.
Volume Converter
Convert volume: ml, litres, cups, fluid ounces, pints, quarts and US or UK gallons.
Speed Converter
Convert speed: km/h, mph, m/s, knots, feet per second and Mach.
Data Storage Converter (MB, GB, TB)
Convert data sizes: bits, bytes, KB, MB, GB, TB and binary KiB, MiB, GiB, TiB.
Time Unit Converter
Convert time units: milliseconds, seconds, minutes, hours, days, weeks, months and years.