Time Format Converter

Free Online DateTime Conversion Tool

Time Format Converter is a free online tool that converts datetime data between various standard formats. Supports ISO 8601, RFC 2822, RFC 3339, Unix timestamp (epoch time), SQL format, and other major formats used in development. Includes timezone conversion capabilities, perfect for API development, database integration, and log analysis.

How to Use

Using the Time Format Converter is simple:

Step 1: Enter Date and Time
Enter the datetime you want to convert. You can input in ISO8601 format, Unix timestamp, or other standard formats. Get current datetime is also available.
Step 2: Select Format
Select the output format. Choose from ISO 8601, RFC 2822, RFC 3339, Unix timestamp, SQL format, ATOM, W3C, and more.
Step 3: View and Copy Results
Converted datetime will be displayed instantly. Multiple formats can be viewed simultaneously. Copy the format you need.

Your input data is never stored on our servers. All processing is done in your browser, ensuring complete privacy protection.

Enter Date and Time

Practical Use Cases for Time Format Conversion

Time format conversion is essential in web development and system development for scenarios such as:

API Development and RESTful Communication

RESTful APIs commonly exchange timestamps in ISO 8601 format (e.g., 2024-10-21T15:30:00Z). This tool easily converts between Unix timestamp and ISO format, or vice versa.

Database Integration (SQL Format ⇔ ISO8601)

Convert between MySQL/PostgreSQL DATETIME format (2024-10-21 15:30:00) and ISO 8601 format used in applications. Useful for ORM and API-to-database data conversion.

Log File Analysis and Standardization

Log files from different systems often have inconsistent datetime formats. This tool helps standardize formats for easier log analysis and time-series analysis.

Timezone Conversion (UTC ⇔ Local Time)

Convert between UTC time used on servers and local timezones (JST, EST, etc.) for users. Essential for global application development.

Unix Timestamp Debugging and Readability

Convert Unix timestamps (e.g., 1729491000) stored in logs or databases to human-readable format (2024-10-21 15:30:00) for efficient debugging.

RSS/ATOM Feed DateTime Generation

RSS 2.0 requires RFC 2822 format (Mon, 21 Oct 2024 15:30:00 +0900), while ATOM feeds require RFC 3339 format. Verify correct formats for feed generation.

JavaScript Development and Browser Integration

Convert between JavaScript Date objects and server-side datetime data. Useful for verifying toISOString() results and format compatibility.

Understanding Time Formats and Major Standards

Time formats (datetime formats) are standardized notation methods for exchanging datetime data between computer systems. They enable consistent data exchange between different programming languages, databases, and APIs.

Major Time Format Standards

ISO 8601: International standard datetime notation (e.g., 2024-10-21T15:30:00+09:00)
RFC 2822: Datetime format for email headers (e.g., Mon, 21 Oct 2024 15:30:00 +0900)
RFC 3339: For Internet protocols (subset of ISO 8601)
Unix Timestamp: Seconds elapsed since January 1, 1970 00:00:00 UTC (e.g., 1729491000)
SQL/MySQL Format: Database format (e.g., 2024-10-21 15:30:00)

How ISO 8601 Format Works

ISO 8601 is an international standard defined by the International Organization for Standardization (ISO) for datetime notation. The format YYYY-MM-DDTHH:MM:SS±HH:MM clearly expresses year, month, day, hour, minute, second, and timezone. The 'T' separates date and time, while '±HH:MM' indicates offset from UTC.

Format Examples (Same Moment in Time)

ISO 8601: 2024-10-21T15:30:00+09:00
RFC 2822: Mon, 21 Oct 2024 15:30:00 +0900
Unix Timestamp: 1729491000
SQL Format: 2024-10-21 15:30:00

The timezone notation '+09:00' indicates Japan Standard Time (JST), which is 9 hours ahead of UTC.

Benefits and Use Cases of Time Format Conversion

Data Compatibility Between Systems

Accurately exchange datetime data between different programming languages, databases, and APIs. Format standardization prevents data interpretation errors and corruption.

Accurate Timezone Management

Proper timezone management is essential for global applications. Convert between UTC and local time to display correct times to users worldwide.

Efficient Debugging and Log Analysis

Converting Unix timestamps and machine-readable formats to human-readable formats significantly improves log file analysis and debugging efficiency.

Compliance with International Standards

Adhering to international standards like ISO 8601 and RFC ensures smooth integration with other systems and services, while maintaining future extensibility.

Important: Timezone and Precision Considerations

When using time format conversion, be aware of the following:

Timezone Verification is Critical

UTC vs Local Time

Server-side data is typically stored in UTC (Coordinated Universal Time)
Convert to local timezone when displaying to users
Always specify timezone explicitly (+09:00, etc.)
Be aware of Daylight Saving Time (DST) transitions

Unix Timestamp Limitations

32-bit signed integer has Year 2038 problem (January 19, 2038)
Use 64-bit integer to resolve this issue
Use 13-digit timestamp for millisecond precision
Negative values represent dates before 1970

Timestamps cannot be used for authentication or security tokens. Since anyone can generate or modify timestamps, use signed tokens like JWT for authentication.

Appropriate Usage

Datetime data exchange in API communication
Conversion between database and application
Log file analysis and standardization
Authentication tokens (use signed tokens like JWT instead)
High-precision timing measurements (use dedicated timer APIs)

For leap second considerations or Daylight Saving Time handling, consult the documentation of your programming language or library.

Frequently Asked Questions (FAQ)

What's the difference between ISO 8601 and RFC 3339?

RFC 3339 is a subset of ISO 8601. While ISO 8601 allows very flexible notation, RFC 3339 is more strictly defined for Internet use. In practice, using RFC 3339 format (YYYY-MM-DDTHH:MM:SSZ) is also valid ISO 8601.

What's the maximum Unix timestamp? What's the Year 2038 problem?

With 32-bit signed integer representation, the maximum Unix timestamp is 2147483647 (January 19, 2038 03:14:07 UTC). Beyond this, overflow occurs (Year 2038 problem). The solution is to use 64-bit integers. Modern systems have largely migrated to 64-bit.

How should timezones be handled?

Best practice is to use UTC (Coordinated Universal Time) for databases and API communication, converting to local timezone when displaying to users. Explicitly specify timezone in ISO 8601 format (+09:00, etc.) to avoid confusion.

Is Daylight Saving Time (DST) automatically considered?

If using timezone libraries (JavaScript's Intl.DateTimeFormat, Python's pytz, etc.), DST is automatically considered. However, if using UTC time, DST has no effect.

Does it support milliseconds or microseconds?

Yes. ISO 8601 represents them with decimal points (2024-10-21T15:30:00.123+09:00), Unix timestamp uses 13 digits (milliseconds) or 16 digits (microseconds). JavaScript's Date.now() returns millisecond timestamp.

Are there limits on past or future dates?

Unix timestamp can theoretically represent dates before 1970 (negative values), but some systems have limitations. ISO 8601 has no restrictions and can even represent BC dates (using minus sign).

What's the compatibility with JavaScript Date objects?

JavaScript's new Date().toISOString() returns ISO 8601 format (UTC). Date.parse() can parse ISO 8601 format. Unix timestamp can be obtained with Date.now() or new Date().getTime() (in milliseconds).

What's the recommended format for database storage?

Use MySQL/PostgreSQL DATETIME or TIMESTAMP types, standardizing timezone to UTC. Convert to ISO 8601 format at application layer. NoSQL databases sometimes use Unix timestamp (numeric type).