🔄 Converters Tools

Convert colours between HEX, RGB, HSL, HSV and CMYK, with a live preview — and the reasons a colour picked on screen will not print the same way.

Convert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36, with the digit breakdown that shows how the value is built.

Convert Unix timestamps to readable dates and back, in local time and UTC, including milliseconds — with the 2038 problem that still lurks in 32-bit systems.

Convert length, weight, temperature, volume and more between metric and imperial, with exact factors marked and the US and imperial split handled.

Convert between Celsius, Fahrenheit and Kelvin at once, with reference points from absolute zero to boiling, and the formulas for each direction.

Convert kilograms to pounds and back, with a reference table for body weight, luggage limits and recipes. A pound is exactly 0.45359237 kg.

Convert miles to kilometres and back, with a reference table for road distances, running events and speed limits. A mile is defined as exactly 1.609344 km.

Convert inches to centimetres and back, with a reference table for heights and screen sizes. An inch is exactly 2.54 cm, so results are exact.

Add and subtract durations in hours, minutes and seconds, and see the total in every unit — including decimal hours for payroll.

Convert between miles per gallon, litres per 100 km and km per litre, for both US and imperial gallons. MPG and L/100km run in opposite directions.

Convert shoe sizes between US, UK, EU and centimetres for men, women and children, with a warning that brand sizing varies enough to make charts approximate.

Convert CSV data to JSON in the browser, handling quoted fields, embedded commas and line breaks — the cases that defeat a naive split on commas.

Convert Roman numerals to numbers and back using the standard subtractive rules, with why the system has no zero and no easy way past 3,999.

Convert JSON to CSV in the browser, flattening nested objects and handling the arrays and missing keys that have no natural representation in a flat table.

Translate text to Morse code and back, with the timing rules that make Morse readable by ear rather than just a sequence of dots and dashes.

Work out missing width or height for a target aspect ratio, and identify the ratio of any dimensions you have — for video, print, screens and social media.

Convert text to binary and back, byte by byte, showing how characters become numbers and how encoding decides which number stands for which character.

Convert height between feet-and-inches and centimetres, in the format heights are quoted in — including the decimal-feet trap that adds inches.

Estimate how long a download or upload takes from file size and connection speed, allowing for the overhead that makes real transfers slower.

Convert between bytes, kilobytes, megabytes, gigabytes and terabytes in decimal and binary units — the difference that makes a 1 TB drive show as 931 GB.

Convert cooking measures between cups, spoons, millilitres, grams and ounces, with per-ingredient weights because a cup of flour is not a cup of sugar.

Convert cups to grams for specific ingredients, because the answer depends entirely on what is in the cup — flour, sugar, butter and rice all weigh differently.

Convert millimetres to inches and back, with fractional inch equivalents for hardware, timber and drill sizes where decimals are not what anyone actually uses.

Convert centimetres to feet and inches, and back again — built for heights, where the answer needs to come out as feet plus inches rather than a decimal.

Convert metres to feet and back, with the exact definition, mental shortcuts, and the cases where the difference between the two actually matters.

Convert grams to ounces and back for cooking, post and precious metals — including the troy ounce for gold, which is heavier than the ordinary one.

Convert pounds to stones and pounds, and back — the format British body weight is still quoted in, where 1 stone is exactly 14 pounds.

Convert millilitres to fluid ounces and back, for both the US and imperial fluid ounce — which are not the same size, and differ by about four per cent.

Convert litres to gallons and back for both US and imperial gallons, which differ by about 20 per cent — a costly confusion if you miss it.

Convert tablespoons to teaspoons and back, including the Australian tablespoon that holds four teaspoons instead of three and quietly breaks imported recipes.

Convert Celsius to Fahrenheit and back, with reference points for weather, cooking and body temperature, plus mental shortcuts for everyday use.

Convert square metres to square feet and back, for floor areas, property listings and flooring orders — where the squared conversion factor catches people out.

Convert hectares to acres and back, with the reference points that make land area intuitive — a football pitch, a city block, a square mile.

Convert kilometres per hour to miles per hour and back, with the common speed limits in both systems and the mental shortcuts that work at driving speeds.

Convert megabits per second to megabytes per second and back — the eight-fold difference that explains why a 100 Mbps connection downloads at about 12 MB/s.

Convert degrees to radians and back, with exact multiples of pi for the common angles — the form trigonometry and programming languages actually expect.

Estimate video and audio file sizes from bitrate and duration, with codec presets and upload time — the arithmetic behind every export dialog.

Convert between JSON, YAML, TOML, INI and XML in any direction — with the places where a conversion cannot be faithful.

Turn a file or text into a data URI you can embed directly in HTML or CSS — and know when that is the wrong choice.

Convert text between Base32, Base58, hex, binary, character codes, punycode and quoted-printable — with what each is actually for.

Convert between world currencies using up-to-date rates — with a clear explanation of why the rate you see is not the rate you get.

20 lb bond and 50 lb text are the same paper. US basis weight depends on a parent sheet that differs by paper type.