Category
Converters
Units, number bases, colours and time zones
Convert length, weight, temperature, volume, area, speed, data, time, pressure, energy and angle between exact units — plus number bases, roman numerals, decimal to fraction, colours and time zones. Instant and private in your browser.
At a glance
76tools in this hub
76 of 76 run entirely in your browser
Free · no sign-up · no watermark
All Converters tools
Every tool in converters
Ordered as they appear in the library. Each opens on its own page with instructions, FAQs and related tools.
Unit Converter
Converters
Convert length, weight, temperature, volume, area, speed, data and time in a single unit converter.
Instant · no upload
Cm to Inches Converter
Converters
Convert cm to inches instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Inches to Cm Converter
Converters
Convert inches to cm instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Metres to Feet Converter
Converters
Convert metres to feet instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Feet to Metres Converter
Converters
Convert feet to metres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Km to Miles Converter
Converters
Convert km to miles instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Miles to Km Converter
Converters
Convert miles to km instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Mm to Inches Converter
Converters
Convert mm to inches instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Metres to Cm Converter
Converters
Convert metres to cm instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Km to Metres Converter
Converters
Convert km to metres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Feet to Inches Converter
Converters
Convert feet to inches instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Yards to Metres Converter
Converters
Convert yards to metres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kg to Lbs Converter
Converters
Convert kg to lbs instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Lbs to Kg Converter
Converters
Convert lbs to kg instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Grams to Oz Converter
Converters
Convert grams to oz instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Oz to Grams Converter
Converters
Convert oz to grams instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kg to Grams Converter
Converters
Convert kg to grams instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Lbs to Oz Converter
Converters
Convert lbs to oz instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kg to Stone Converter
Converters
Convert kg to stone instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Celsius to Fahrenheit Converter
Converters
Convert celsius to fahrenheit instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Fahrenheit to Celsius Converter
Converters
Convert fahrenheit to celsius instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Celsius to Kelvin Converter
Converters
Convert celsius to kelvin instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Litres to Gallons Converter
Converters
Convert litres to gallons instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Gallons to Litres Converter
Converters
Convert gallons to litres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Ml to Litres Converter
Converters
Convert ml to litres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Cups to Ml Converter
Converters
Convert cups to ml instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Tbsp to Ml Converter
Converters
Convert tbsp to ml instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Km/H to Mph Converter
Converters
Convert km/h to mph instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Mph to Km/H Converter
Converters
Convert mph to km/h instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Sq Metres to Sq Feet Converter
Converters
Convert sq metres to sq feet instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Sq Feet to Sq Metres Converter
Converters
Convert sq feet to sq metres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Acres to Sq Metres Converter
Converters
Convert acres to sq metres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Hectares to Acres Converter
Converters
Convert hectares to acres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Mb to Gb Converter
Converters
Convert mb to gb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Gb to Mb Converter
Converters
Convert gb to mb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kb to Mb Converter
Converters
Convert kb to mb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Gb to Tb Converter
Converters
Convert gb to tb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Hours to Minutes Converter
Converters
Convert hours to minutes instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Minutes to Hours Converter
Converters
Convert minutes to hours instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Days to Hours Converter
Converters
Convert days to hours instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kpa to Psi Converter
Converters
Convert kpa to psi instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Psi to Kpa Converter
Converters
Convert psi to kpa instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kj to Kcal Converter
Converters
Convert kj to kcal instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kcal to Kj Converter
Converters
Convert kcal to kj instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Degrees to Radians Converter
Converters
Convert degrees to radians instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Radians to Degrees Converter
Converters
Convert radians to degrees instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Inches to Mm Converter
Converters
Convert inches to mm instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Mm to Cm Converter
Converters
Convert mm to cm instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Yards to Feet Converter
Converters
Convert yards to feet instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Feet to Cm Converter
Converters
Convert feet to cm instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Nautical Miles to Km Converter
Converters
Convert nautical miles to km instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Stone to Lbs Converter
Converters
Convert stone to lbs instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Tonnes to Kg Converter
Converters
Convert tonnes to kg instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Grams to Kg Converter
Converters
Convert grams to kg instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Oz to Lbs Converter
Converters
Convert oz to lbs instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Kelvin to Celsius Converter
Converters
Convert kelvin to celsius instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Fahrenheit to Kelvin Converter
Converters
Convert fahrenheit to kelvin instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Teaspoons to Ml Converter
Converters
Convert teaspoons to ml instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Pints to Litres Converter
Converters
Convert pints to litres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Uk Gallons to Litres Converter
Converters
Convert uk gallons to litres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Litres to Cups Converter
Converters
Convert litres to cups instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Knots to Km/H Converter
Converters
Convert knots to km/h instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Km/H to M/S Converter
Converters
Convert km/h to m/s instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Acres to Hectares Converter
Converters
Convert acres to hectares instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Sq Km to Acres Converter
Converters
Convert sq km to acres instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Mb to Kb Converter
Converters
Convert mb to kb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Tb to Gb Converter
Converters
Convert tb to gb instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Weeks to Days Converter
Converters
Convert weeks to days instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Hours to Seconds Converter
Converters
Convert hours to seconds instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Bar to Psi Converter
Converters
Convert bar to psi instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Joules to Calories Converter
Converters
Convert joules to calories instantly, in your browser — nothing uploaded and no sign-up.
Instant · no upload
Decimal to Fraction Converter
Converters
Turn any terminating decimal into a simplified fraction, exactly — a decimal to fraction converter with no rounding.
Instant · no upload
Roman Numeral Converter
Converters
This Roman numeral converter changes whole numbers into Roman numerals and reads Roman numerals back as numbers.
Instant · no upload
Number Base Converter (Binary, Octal, Hex)
Converters
This number base converter switches a whole number between binary, octal, decimal and hexadecimal.
Instant · no upload
Colour Converter
Converters
Convert between HEX, RGB, HSL, HSV and CMYK with a live preview — a colour converter that runs on your device.
Instant · no upload
Timezone Converter
Converters
Convert a time between any two timezones and see a full overlap chart with this timezone converter.
Instant · no upload
About this category
What converters can do for you
Seventy-odd dedicated converters, each answering one exact question — cm to inches, kg to lbs, celsius to fahrenheit — the way people actually search, plus number-base, roman-numeral, decimal-to-fraction, colour and timezone converters. Every factor is the defined one rather than a measured approximation, and the arithmetic runs in your browser, so nothing you type is ever sent anywhere.
Seventy-odd converters, one exact question each. They are grouped by the kind of quantity, and the single most useful thing to know is that conversion here is arithmetic on defined constants, not a measured approximation — an inch is exactly 0.0254 metres, a pound is exactly 0.45359237 kilograms, an acre is exactly 4,046.8564224 square metres. Only the display rounds.
Start with the Unit Converter if you want every unit in a group at once, or jump straight to a dedicated pair such as Cm to Inches, Kg to Lbs, Km to Miles, Celsius to Fahrenheit or Mb to Gb when you want that one conversion explained and worked.
Temperature is affine, not a multiplier
Celsius, Fahrenheit, Kelvin and Rankine are offset scales with arbitrary zero points, so they convert by an offset and a scale rather than one factor. Fahrenheit to Celsius is subtract 32, then multiply by five ninths — and doing those two steps in the wrong order produces a number that looks plausible and is wrong. Celsius to Fahrenheit, Fahrenheit to Celsius and Celsius to Kelvin show the formula rather than a multiplier for exactly that reason. Minus forty is the one reading identical on the Celsius and Fahrenheit scales.
Digital storage has two competing definitions
A kilobyte is 1,000 bytes in decimal SI usage and 1,024 in the binary usage operating systems grew up with; the binary units have their own names — kibibyte, mebibyte, gibibyte. By the gigabyte the two are about 7.4% apart, which is why a drive sold as 1 TB shows up as roughly 931 GB. Mb to Gb, Gb to Tb and Kb to Mb use the decimal definition, and the binary units sit alongside them in the full converter. Drive makers, file systems and network providers each pick a different one, so the useful habit is checking which you are being quoted.
Kitchen measures are the genuinely ambiguous ones
A US cup is exactly 236.588 millilitres and a US tablespoon exactly 14.787, and Cups to Ml and Tbsp to Ml use those figures. But a metric cup in Australia and New Zealand is 250 ml and the old imperial cup was 284 ml. A recipe rarely says which it means, and a 5% error in flour is the difference between workable dough and a dry one. The same ambiguity applies to gallons: Gallons to Litres uses the US gallon of 3.785 litres, while Uk Gallons to Litres uses the imperial 4.546. For anything baked rather than stirred, weighing beats converting — Grams to Oz and Oz to Grams are the pair that matters, because a scale has no cups.
Time, and the average month
Every duration unit is exact except the calendar ones. A month is not a fixed length, so where a month or year has to be treated as a duration the averages are used — 2,629,800 seconds and 31,557,600 — because calendar months run 28 to 31 days. Hours to Minutes, Days to Hours and Weeks to Days are exact; anything claiming thirty days equals one month is approximating.
Beyond units: numbers, colours and time zones
Not every converter here is a measurement. Number Base Converter switches a whole number between binary, octal, decimal and hexadecimal; Roman Numeral Converter covers 1 to 3,999 and validates by round-tripping through the canonical form, so IIII and VX are rejected; Decimal to Fraction Converter parses the digits you typed rather than a floating-point value, so 0.75 is exactly three quarters. Colour Converter pivots on RGB — HEX is RGB written in base sixteen and the other models are functions of the three channels — and Timezone Converter uses the IANA database and handles daylight saving correctly. Same rule as the units: exact, in your browser, nothing uploaded.
None of it leaves the page
Every conversion runs in your own browser with the same defined constants, so the figures are identical offline and online, nothing you type is transmitted, and closing the tab discards it. That is the whole reason these are client-side rather than a server endpoint.
Questions
Converters tools, answered
The things people ask before choosing a tool, rather than while using one.
Why does a 1 TB drive show as 931 GB on my computer?
Are these conversion factors exact or rounded?
Which gallon and which cup does the converter use?
Is any of my data uploaded when I convert?
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