Unit and Timestamp Converters
Two converters live here. The Unit Converter takes one value and shows it in every other unit of the same kind at once: length, temperature, area, volume, weight and time, from nanometres to light years and millilitres to UK gallons. The Time Converter turns Unix timestamps in seconds, milliseconds or nanoseconds into dates and back, with a live clock for UTC, your own zone and one more. Students, cooks, travellers and developers reading logs use them.
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All Converters (2)
Which tool do I need?
Convert Fahrenheit to Celsius or miles to kilometres
Pick the category and source unit, type the value and read every other unit in the list.
Turn a Unix timestamp in a log into a readable date
Choose the right unit, paste the number and click From Unix to see UTC, local time and how long ago it was.
Get the current Unix time for a test or API call
Pick the current date and time and click To Unix, or read the live clock card for UTC.
About Converters
Other conversions sit in neighbouring subcategories. Date arithmetic and date differences are in Calculation Tools, a multi-city world clock is in Time Utilities, the audio format converter is in Text & Speech Tools, and Base64, URL and HTML encoding are in Encoding Tools. For a debugging session the usual path is to convert the timestamp here, then use the date difference calculator to see how long ago it happened in business days.
A few traps catch people. US and UK gallons, pints and fluid ounces are different sizes, and both are listed. A year in the unit converter is the Julian year of 365.25 days. Results of 1 or more include your locale's thousands separators, which break pasting into code. With timestamps, a date in January 1970 means a seconds value was read as milliseconds, and a date thousands of years ahead means the reverse.
Guides
- Unit Conversion Factors: Exact Definitions, Gallons and Temperature OffsetsWhy an inch is exactly 2.54 cm, why US and UK gallons differ by 20%, and why temperature cannot be converted with a single multiplication factor.
- Master Unix Epoch Time Conversion: Complete Developer Guide to Timestamp ProcessingMaster Unix epoch time conversion with our comprehensive guide. Learn timestamp formats, conversion techniques, and best practices for handling time data in software development.
- Time Zones for Developers: Offsets, DST and IANA Zone NamesA UTC offset is not a time zone. How the IANA database works, what happens to 02:30 on a DST night, and the rules that keep scheduling code out of trouble.
Frequently asked questions
Why do US and UK gallons give different answers?
They are different units. A US gallon is about 3.785 litres and an imperial (UK) gallon about 4.546 litres, and the same split applies to pints and fluid ounces. Check which one a recipe or spec means.
How do I recognise a timestamp in milliseconds?
Count the digits. A current Unix time in seconds has 10 digits, in milliseconds 13 and in nanoseconds 19. JavaScript Date.now() gives milliseconds; most Unix tools and databases use seconds.
Can these converters handle currency?
No. Currency rates change by the minute and need a live data feed. The unit converter only covers fixed physical units with exact or defined conversion factors.
Where do I calculate the difference between two dates?
In Calculation Tools. The date difference calculator gives total days, weeks and business days, and date arithmetic adds or subtracts days, months or years from a date.