Read application logs
Turn an epoch value into an ISO and UTC time while correlating events across services.
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Time Converter
Convert Unix timestamps in seconds or milliseconds and ISO date strings to ISO, UTC, local time, and both Unix units in your browser.
Use Timestamp converter now.
Convert Unix timestamps and ISO dates. Your result updates in the current tab as you work.
Time Converter
Convert Unix timestamps and ISO dates. Nothing you enter here is uploaded or stored.
Converted time
ISO: 2026-09-16T23:32:19.000Z UTC: Wed, 16 Sep 2026 23:32:19 GMT Local: 9/16/2026, 11:32:19 PM Unix seconds: 1789601539 Unix milliseconds: 1789601539000
WHAT IT DOES
Useful when a small detail is blocking the next step.
Timestamps cross system boundaries constantly: logs use Unix time, APIs often return ISO 8601 strings, and a user sees their local time. Time Converter accepts a 10-digit Unix value in seconds, a 13-digit value in milliseconds, or a valid ISO date, then shows equivalent forms side by side.
Check API dates
Confirm whether an endpoint returns seconds, milliseconds, or a timezone-aware ISO value.
Plan a migration
Compare an exported date field with the numeric timestamp expected by another system.
WORKED EXAMPLES
See the exact decision the tool can help you make.
These examples are specific to Timestamp converter. Replace their values with your own, then use the result as a clue—not as a substitute for application validation.
Recognize JavaScript milliseconds
A client log reports 1735689600000.
INPUT
1735689600000
RESULT
Unix milliseconds → 2025-01-01T00:00:00.000Z
Thirteen digits indicate milliseconds. Passing that value to an API expecting seconds creates a date tens of thousands of years away.
Keep an offset intact
An API sends 2026-09-14T09:30:00+01:00.
INPUT
2026-09-14T09:30:00+01:00
RESULT
UTC equivalent → 2026-09-14T08:30:00.000Z
The offset tells you the represented instant. Converting to UTC makes cross-service comparison reliable.
HOW TO USE IT
Three deliberate steps.
Use the result to make a decision in your code or content, not merely to produce another value to copy.
- 01
Identify the input format
Ten digits usually represent Unix seconds; thirteen digits usually represent milliseconds; ISO values should include their timezone when possible.
- 02
Read UTC before local time
UTC is the shared reference for logs and APIs. Local display is useful for human context only.
- 03
Preserve timezone information
A date without an offset can be interpreted differently by different runtimes and users.
Store an instant, display a locale
For a moment in time, store a timezone-aware ISO timestamp or epoch value, then format it for the viewer’s locale at the edge of your interface. Do not store a human-formatted date as your source of truth.
A log event is an instant and can be stored in UTC. ‘Every weekday at 09:00 in Casablanca’ is a local-time rule that must retain a timezone and handle daylight-saving changes where applicable.
Instant: 2026-09-14T08:30:00.000Z
Schedule: { time: "09:00", zone: "Africa/Casablanca", days: [1,2,3,4,5] }COMMON PITFALLS
Use the result without creating the next bug.
Each tool is deliberately narrow. These are the mistakes most likely to appear when its output is copied into a real product without checking the surrounding constraint.
Inferring the timestamp unit from the programming language alone.
Why it matters: JavaScript Date uses milliseconds, but many APIs and databases expose seconds.
Better approach: Name fields explicitly—createdAtMs or createdAtSeconds—and validate their magnitude at the boundary.
Scheduling with a timezone-free date-time string.
Why it matters: The same string can become different instants for different users or runtimes.
Better approach: Send an ISO offset or IANA timezone alongside local calendar information.
FAQ
Questions worth answering before you rely on the result.
These tools help with bounded client-side work. Production decisions still need the validation, review, and authorization appropriate to your application.
01What is the difference between seconds and milliseconds?
Unix seconds have ten digits for current dates; JavaScript Date values use milliseconds and commonly have thirteen. Supplying the wrong unit shifts the date dramatically.
02Why is UTC different from local time?
UTC is a global reference. Local time applies the browser’s timezone and daylight-saving rules for display.
03Can I use a date without a timezone?
You can, but it is ambiguous. Prefer an ISO value ending in Z for UTC or including an explicit offset such as +01:00.
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