Convert and Format JavaScript Dates & Times

Work with JavaScript dates effortlessly. Convert between timestamps, date objects, and formatted strings across different timezones.

Convert and Format JavaScript Dates & Times

Work with JavaScript dates, timestamps, and timezones effortlessly.

Date (or leave empty for now)

Result

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How the JavaScript Date & Time Converter Works

Choose your conversion mode: Date to Timestamp, Timestamp to Date, Format Date, or Add/Subtract time. Enter your input value or leave empty for the current date/time.

For formatting, use custom patterns like YYYY-MM-DD HH:mm:ss. The converter supports all common date tokens. For manipulation, specify the amount and unit (days, hours, months, etc.).

Results show multiple formats: locale string, ISO string, UTC string, and Unix timestamp. Copy any format with one click. All calculations use JavaScript's native Date object.

When You'd Actually Use This

Converting API timestamps

APIs return Unix timestamps. Convert to readable dates for display. Or convert user dates to timestamps for API requests.

Formatting dates for display

Need dates in a specific format? Generate the format string, then use it in your code. No more guessing date format tokens.

Calculating future/past dates

What date is 30 days from now? Add or subtract time units easily. Handle month/year boundaries correctly without manual calculation.

Debugging timezone issues

See the same date in local time, UTC, and ISO format. Understand timezone conversions. Debug why dates appear wrong in different regions.

Working with database dates

Databases store dates differently. Convert between Unix timestamps, ISO strings, and locale formats. Match your database's expected format.

Learning JavaScript Date

JavaScript dates are confusing. Experiment with conversions to understand timestamps, timezones, and formatting. Build intuition for date handling.

What to Know Before Using

JavaScript months are zero-indexed.January is 0, December is 11. This trips up everyone. The converter handles this correctly, but remember it for your own code.

Timestamps are in milliseconds.JavaScript uses milliseconds since epoch. Unix timestamps are seconds. The converter shows both. Multiply/divide by 1000 to convert.

Timezone matters for display.Dates display in your local timezone. ISO strings include timezone info. UTC is timezone-independent. Know which you need.

Month arithmetic is tricky.Adding months doesn't always give expected results. Jan 31 + 1 month = Feb 28 (or 29). The converter handles edge cases.

Pro tip: For production date handling, use libraries like date-fns or Day.js. They handle edge cases and provide better APIs. This tool is great for quick conversions and learning.

Common Questions

What's the Unix epoch?

January 1, 1970, 00:00:00 UTC. Timestamps count seconds or milliseconds since then. Negative values are dates before 1970.

Why are my dates off by one day?

Timezone conversion issue. Your local date may be yesterday/tomorrow in UTC. Use ISO strings with timezone info for clarity.

How do I parse custom date formats?

JavaScript's Date.parse() is limited. For custom formats, use a library or manual parsing. This tool converts from Date objects, not arbitrary strings.

Can I convert between timezones?

This shows local and UTC. For specific timezone conversion, use Intl.DateTimeFormat with timeZone option or a library like Luxon.

What's ISO 8601 format?

Standard date format: YYYY-MM-DDTHH:mm:ss.sssZ. Used by JavaScript's toISOString(). Universally understood and sortable.

How accurate is the reading time?

This is for dates, not reading time. Date calculations are exact within JavaScript's precision limits (milliseconds).

Does it handle leap years?

Yes, JavaScript's Date object handles leap years automatically. Feb 29 exists in leap years. Date arithmetic accounts for this.

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Convert and Format JavaScript Dates & Times