JavaScript Date Format Tester

Summary

Pick a locale and Intl.DateTimeFormat options to preview live JavaScript date formatting across multiple sample dates.

How it works

1. Select a locale from the dropdown (e.g. en-US, de-DE, ja-JP) or type a custom BCP 47 tag.
2. Toggle the date and time component options — weekday, year, month, day, hour, minute, second.
3. Choose a display style (long, short, narrow, numeric, 2-digit) for each active option.
4. The formatted output updates live for the current date and six sample dates.
5. Copy the generated Intl.DateTimeFormat code snippet with one click.

Use cases

• Preview how a date looks for users in different regions before shipping.
• Find the right combination of options for a localized UI date display.
• Debug unexpected date formatting behavior in your JavaScript app.
• Generate the exact Intl.DateTimeFormat constructor call to paste into code.
• Compare numeric vs. long month styles across multiple locales at a glance.
• Test edge-case dates like leap day, New Year, and year-end formatting.

Frequently Asked Questions