DateUtils

Date Converters

Date converters change the representation of a date without changing which day it is: from a day-first format to a month-first one, from a date to its position in the year, or from a Unix timestamp to a readable date.

Ambiguous numeric dates such as 04/03/2024 mean different days in different countries, so these tools label every format explicitly and let you copy exactly the one you need.

Tools in this category

Date Formatter Show a date in common formats and copy the one you need. Unix Timestamp Convert Unix timestamps to dates and dates to Unix timestamps. Date to Day Number Convert a date to its day number in the year, or a day number back to a date.

Which tool do you need?

  • What are the DD/MM/YYYY, MM/DD/YYYY and ISO forms of a date? The Date Formatter shows them side by side with copy buttons.
  • Which day of the year is a date, or which date is day 200? Date to Day Number converts in both directions.
  • What does a Unix timestamp mean? The Unix Timestamp Converter works in seconds and milliseconds, before 1970 and after 2038.

Good to know

A date with no time of day has no single Unix timestamp. Where these tools show one for a date they state that it is midnight UTC at the start of that date.

Background reading

  • Days in each month A table of month lengths, the day of the year each month starts on, quarter lengths, and how to remember which months have 30 or 31 days.
  • Unix time What a Unix timestamp counts, how to tell seconds from milliseconds, negative timestamps, the year 2038 problem and why leap seconds are ignored.
  • Time zones and daylight saving UTC offsets, IANA zone names, why abbreviations are ambiguous, how daylight saving creates skipped and repeated times, and why the gap between two cities changes.