Convert a date
Month lengths
Despite the slug, this is a single-date tool: pick one day, choose an output format, and get rewritten strings plus calendar facts (weekday, quarter, day-of-year, leap-year flag, Unix timestamp). It does not convert “3 months” into a date range.
What you get after Convert
Pick a date and this page rewrites it in the format you need and describes where it falls in the calendar. It is useful when a form demands a specific date order, or when you need to know the quarter, week number or weekday for a given day.
To be clear about the name, this tool does not turn a number of months into a date range. It works on one date at a time and reformats and analyses it.
Available Formats
- DD/MM/YYYY, the day-first order used across India, the UK and much of Europe.
- MM/DD/YYYY, the month-first order used in the United States.
- YYYY-MM-DD, the sortable order used in databases and spreadsheets.
- Full text, such as 17 August 2026, for letters and printed documents.
- ISO 8601, the standard machine-readable form.
Steps
- Choose the input date.
- Select the output format (DD/MM/YYYY, MM/DD/YYYY, YYYY-MM-DD, long text, or ISO 8601).
- Click Convert & Analyse.
- Copy the formatted line or read the analysis block.
Why DD/MM and MM/DD collide
A date such as 03/04/2026 is genuinely ambiguous. Read day-first it is 3 April; read month-first it is 4 March. Any date where both parts are twelve or below can be misread, which is a common source of errors in spreadsheets and forms.
The YYYY-MM-DD order avoids the problem entirely and has the useful property that sorting the text alphabetically also sorts it chronologically. That is why databases and log files prefer it.
Limits
- Midnight is interpreted in your device time zone; ISO strings can shift near UTC boundaries.
- Week number is a simple count from 1 January—not ISO week 1 rules.
- Leap years use the Gregorian rule (÷4, except centuries unless ÷400).
Processing
All formatting runs in JavaScript in this tab.
Date format questions
What does this tool convert?
It takes one date and rewrites it in a different format, then reports calendar details about it such as the weekday, week number and quarter. Despite the page address, it does not convert a number of months into a date range.
Why is 03/04/2026 ambiguous?
Read day-first it is 3 April; read month-first it is 4 March. Any date where both the day and month are twelve or below can be misread, which is a frequent source of errors in forms and spreadsheets.
Which date format should I use in a spreadsheet or database?
YYYY-MM-DD. It is unambiguous, and sorting it as text also sorts it chronologically, which is why databases and log files prefer it.
Is the week number the ISO 8601 week number?
No. A simple count from 1 January is used, which can differ from the ISO 8601 standard at the very start and end of a year. If you need strict ISO week numbering, verify it separately.
How is a leap year determined?
By the standard rule: a year divisible by four is a leap year, except century years, unless they are divisible by 400. So 2000 was a leap year and 1900 was not.
Why does the ISO output sometimes show a different day?
The date is read as local midnight, and the ISO form is expressed in UTC. If your time zone is far from UTC, the two can fall on different calendar days.
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