Timestamp Converter

What is Timestamp Converter?

A timestamp converter translates between Unix epoch values (seconds or milliseconds since January 1, 1970 UTC) and human-readable date-time strings in ISO 8601, UTC, and local timezone formats. Unix timestamps are the universal time representation in programming — databases store them as integers, APIs return them in JSON responses, log files embed them in every entry, and JWT exp claims use them for expiration.

The epoch started at 1970-01-01 00:00:00 UTC, chosen as a convenient reference point for early Unix systems. A 10-digit number like 1704067200 represents seconds since epoch (January 1, 2024 00:00:00 UTC). A 13-digit number like 1704067200000 represents milliseconds — common in JavaScript where Date.now() returns millisecond precision. Confusing seconds and milliseconds is the single most frequent timestamp bug in web development.

Our converter accepts Unix timestamps in either format (auto-detecting by digit count), ISO 8601 strings, RFC 2822 dates, and common JavaScript Date parse formats. Output displays ISO 8601 (2024-01-01T00:00:00.000Z), UTC formatted strings, and your browser's local timezone interpretation simultaneously. A 'Current Time' button captures the present moment for quick reference during debugging.

All conversion runs locally in your browser. Log timestamps from production systems, API responses containing user activity data, and authentication token expiration values never upload to external servers. This privacy matters when debugging incidents involving customer sessions, financial transaction times, or security event timelines.

Timestamps frequently appear inside JSON API responses and JWT tokens. After converting, format surrounding JSON with the JSON Formatter, inspect token exp claims with the JWT Decoder, and schedule related cron jobs with the Cron Generator. For comparing log entries across versions, use the Diff Checker.

Backend developers, frontend engineers, DevOps operators, data analysts, and security investigators use timestamp converters when debugging API responses, correlating log entries across distributed systems, verifying JWT and session expiration, converting database epoch columns for reports, and translating user-reported incident times to UTC for investigation.

When should you use Timestamp Converter?

Decode Unix timestamps from API responses, database queries, and application logs into readable dates during debugging.

Convert human-readable dates to Unix epoch values for API requests, database inserts, and test fixtures.

Verify JWT exp and iat claims, session expiration times, and cache TTL values during authentication debugging.

Correlate events across microservices and log aggregators that use different timestamp formats or timezones.

How to Use Timestamp Converter

1. Choose mode: Timestamp to Date or Date to Timestamp.
2. Enter a Unix timestamp or date string.
3. Click Convert to see ISO, UTC, and local formats.
4. Use Current Time for the present moment.

Features

• Convert Unix timestamps (seconds and milliseconds) to readable dates
• Convert date strings to Unix epoch in seconds and milliseconds
• Auto-detect seconds versus milliseconds by digit count
• Display ISO 8601, UTC, and local timezone simultaneously
• Current Time button for instant present-moment reference
• Accept ISO 8601, RFC 2822, and JavaScript Date formats
• 100% browser-based — timestamps never sent to servers
• Instant conversion with no account required

Example

The 10-digit value 1704067200 is interpreted as seconds since Unix epoch. It converts to January 1, 2024 at midnight UTC — the start of 2024. If this were accidentally treated as milliseconds (by adding three zeros: 1704067200000), the result would be a date in 1970, illustrating why digit count detection matters for correct conversion.

1704067200

ISO: 2024-01-01T00:00:00.000Z | UTC: Mon, 01 Jan 2024 00:00:00 GMT

Common Errors

Best Practices

• Store and transmit timestamps in UTC; convert to local time only for display
• Use ISO 8601 strings in JSON APIs for human readability alongside Unix epoch for computation
• Verify digit count (10 vs 13) before converting between seconds and milliseconds
• Use the Current Time button to generate test timestamps for API requests and fixtures
• Document whether your API returns seconds or milliseconds in integration guides
• Correlate log timestamps in UTC across distributed systems for accurate incident timelines
• Check JWT exp claims with this tool during authentication debugging sessions
• Prefer 64-bit integer columns for timestamp storage in databases to avoid Year 2038 issues

Frequently Asked Questions