# Calkoo

> Calkoo is a free online calculator hub covering date & time, unit conversion, geometry, health & fitness, and finance, available in 35+ languages. This file lists the site's highest-traffic calculators, ranked by real Google Search Console click data aggregated across all language versions.

All calculators are free, require no sign-up, and work entirely client-side in the browser.

## Date & Time

- [Age and Date Difference Calculator](https://www.calkoo.com/en/age-and-date-difference-calculator): Find the exact age or time difference between two dates in years, months, weeks, days, hours and minutes.
- [Date Calculator: Add or Subtract Days](https://www.calkoo.com/en/add-or-subtract-dates): Add or subtract days, weeks, or months from any date to find a past or future date.
- [Age Calculator (How Old Am I?)](https://www.calkoo.com/en/how-old-am-i-age-calculator): Find your exact age by date of birth in years, months, weeks, and days.
- [Time Calculator](https://www.calkoo.com/en/time-calculator): Add, subtract, multiply, or divide time in hours, minutes, seconds, and milliseconds.
- [Days Ago Calculator](https://www.calkoo.com/en/days-ago-calculator): Find the exact date and weekday a given number of days in the past.
- [Days From Now Calculator](https://www.calkoo.com/en/days-from-now-calculator): Find the exact date and weekday a given number of days in the future.
- [Time From Now Calculator](https://www.calkoo.com/en/time-from-now-calculator): Find what time it will be a given number of minutes, hours, or days from now.

## Conversion & Numbers

- [Binary Converter](https://www.calkoo.com/en/binary-converter): Convert between decimal, binary, hexadecimal, and octal numbers.
- [Hexadecimal Converter](https://www.calkoo.com/en/hexadecimal-converter): Convert between hexadecimal, decimal, binary, and octal.
- [Roman Numeral Converter](https://www.calkoo.com/en/arabic-roman-numerals-converter): Convert numbers to Roman numerals or Roman numerals to numbers.
- [Body Height / Weight Converter](https://www.calkoo.com/en/body-height-and-weight-converter): Convert cm to feet/inches and kg to lbs.
- [Shoe Size Converter](https://www.calkoo.com/en/shoe-size-converter): Convert shoe sizes between US, UK, EU, cm, mm, Japan, and Korea.

## Geometry & Measurement

- [Speed Calculator](https://www.calkoo.com/en/distance-time-speed-calculator): Find speed, distance, or travel time from any two values.
- [Circle Calculator](https://www.calkoo.com/en/circle-calculator): Find area, circumference, radius, or diameter from any one value.
- [Volume Calculator](https://www.calkoo.com/en/volume-calculator): Calculate volume for common 3D shapes including tank, room, box, and container.
- [Volume of a Cylinder Calculator](https://www.calkoo.com/en/volume-of-a-cylinder-calculator): Find the volume of a cylinder from radius/diameter and height.
- [Area Calculator](https://www.calkoo.com/en/area-calculator): Calculate area for rectangle, triangle, circle, square, and more.

## Health & Lifestyle

- [BAC Calculator](https://www.calkoo.com/en/blood-alcohol-content-calculator): Estimate blood alcohol content from drink volume, ABV, body weight, and sex.
- [Running Pace Calculator](https://www.calkoo.com/en/fitness-pace-and-speed-calculator): Calculate running pace, speed, finish time, or distance for 5K, 10K, half marathon, and marathon.
- [Fuel Cost Calculator](https://www.calkoo.com/en/fuel-cost-calculator): Find trip gas cost from distance, fuel economy, and fuel price.

## Finance

- [VAT Calculator](https://www.calkoo.com/en/vat-calculator): Add or remove VAT from any price.

## Optional

- [All Calculators (A-Z)](https://www.calkoo.com/en/all-calculators): Full index of every calculator on the site.
- [Financial Calculators](https://www.calkoo.com/en/financial-calculators): Loans, NPV, IRR, WACC, bonds, and other finance tools.
- [Math Calculators](https://www.calkoo.com/en/math-calculators): Geometry, algebra, and number-base conversion tools.