# Date Format Converter

Free date format converter. Convert dates between ISO 8601, US (MM/DD/YYYY), European (DD/MM/YYYY), Unix timestamp, and more.

## What this calculates

Convert any date between multiple formats including ISO 8601, US, and European styles. Also shows the day of the week, day of the year, ISO week number, and Unix timestamp.

## Inputs

- **Year** — min 1, max 9999
- **Month** — options: January (1), February (2), March (3), April (4), May (5), June (6), July (7), August (8), September (9), October (10), November (11), December (12)
- **Day** — min 1, max 31

## Outputs

- **ISO 8601** — formatted as text — International standard format (YYYY-MM-DD).
- **US Format** — formatted as text — Month/Day/Year format (MM/DD/YYYY).
- **European Format** — formatted as text — Day/Month/Year format (DD/MM/YYYY).
- **Long Format** — formatted as text — Written out date (Month Day, Year).
- **Day of Week** — formatted as text — The day of the week for this date.
- **Day of Year** — formatted as text — Which day of the year (1-366).
- **ISO Week Number** — formatted as text — ISO 8601 week number.
- **Unix Timestamp** — formatted as text — Seconds since January 1, 1970 (midnight UTC).

## Details

Date formatting varies significantly around the world, often causing confusion. This converter shows a single date in all major formats.

Common Date Formats

- ISO 8601 (YYYY-MM-DD): International standard, unambiguous, sorts chronologically. Used in programming and databases.

- US Format (MM/DD/YYYY): Used primarily in the United States.

- European Format (DD/MM/YYYY): Used in most of Europe, South America, and many other regions.

- Long Format: Written out for clarity (e.g., January 15, 2025).

Additional Information

- Day of Year: Ranges from 1 (Jan 1) to 365/366 (Dec 31).

- ISO Week Number: The ISO 8601 week starts on Monday. Week 1 contains the first Thursday of the year.

- Unix Timestamp: Seconds since midnight UTC, January 1, 1970. Widely used in computing.

## Frequently Asked Questions

**Q: What is ISO 8601 date format?**

A: ISO 8601 is the international standard for date representation: YYYY-MM-DD (e.g., 2025-01-15). It is unambiguous, language-independent, and sorts chronologically as text. It is the preferred format for data exchange, programming, and databases.

**Q: What is a Unix timestamp?**

A: A Unix timestamp is the number of seconds elapsed since midnight UTC on January 1, 1970 (the Unix epoch). For example, 1704067200 represents January 1, 2024. It is widely used in computing because it is timezone-independent and easy to calculate with.

**Q: How do I avoid date format confusion?**

A: Use ISO 8601 (YYYY-MM-DD) whenever possible, as it is unambiguous worldwide. The date 03/04/2025 could mean March 4 (US) or April 3 (Europe). Writing it as 2025-03-04 or 'March 4, 2025' eliminates confusion.

**Q: How is the ISO week number calculated?**

A: ISO 8601 defines week 1 as the week containing the first Thursday of the year (equivalently, the week containing January 4). Weeks start on Monday. A year has 52 or 53 ISO weeks. Some days in late December may belong to week 1 of the next year.

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Source: https://vastcalc.com/calculators/conversion/date-format-converter
Category: Conversion
Last updated: 2026-04-21