What Day Is Today?
Live reference for today’s calendar details in your local timezone. The Unix timestamp updates every second.
Day name
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Full date
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ISO date
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Week number (ISO 8601)
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Day of year
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Days remaining in year
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Julian day number
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Unix timestamp
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Timezone
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Understanding today’s date
Most of the world uses the Gregorian calendar, introduced in 1582 to align the civil year with the solar year. Months have 28–31 days, and leap years add February 29 when the year is divisible by 4 (with exceptions for century years unless divisible by 400). Your browser formats “today” using this system and your device’s regional settings.
Week numbering
ISO 8601 defines weeks as starting on Monday. Week 1 is the week containing the year’s first Thursday. That means some January days belong to week 52 or 53 of the previous ISO year, and late December can fall in week 1 of the next ISO year. It is the standard used in business, logistics, and many APIs.
Fun date facts
- Leap years keep seasons aligned: without them, calendars would drift by roughly one day every four years.
- Day of year (1–365 or 366) is handy for science, telemetry, and batch jobs that index by “nth day.”
- Julian day number counts whole days on a single scale, which makes date differences and astronomical calculations simpler.
Frequently asked questions
What is ISO week number?
ISO 8601 defines weeks as starting on Monday. Week 1 is the week that contains the first Thursday of the calendar year. This can place early January days in the previous year’s week 52 or 53.
What is Julian day number?
The Julian day number (JDN) is a continuous count of days used in astronomy and computing. Each Gregorian calendar date maps to one JDN; it is not the same as the old Julian calendar alone.
Does this page send my data anywhere?
No. All calculations run in your browser using JavaScript. Nothing is uploaded to a server.