Unix Time Converter

About this tool

Unix Time Converter on UtilityKit converts between Unix epoch timestamps and human-readable dates in both directions: paste a raw integer and see the UTC date plus your local timezone equivalent, or pick a calendar date and get the epoch seconds ready for code, APIs, or database queries. Unix time — seconds elapsed since 00:00:00 UTC on 1 January 1970 — is the universal format across backend systems, logs, cloud APIs, and JWT claims. The tool auto-detects scale: 10-digit inputs are seconds; 13-digit inputs are JavaScript milliseconds. Output shows both the ISO 8601 UTC string and your locale-formatted local time. A Now button stamps the current second instantly. The reverse direction accepts a datetime picker and outputs the floor-second integer ready to paste into a curl command, SQL WHERE clause, or JWT exp field.

Why use it

• Auto-Detects Seconds vs Milliseconds: 10-digit inputs are treated as seconds (standard Unix); 13-digit inputs are treated as JavaScript milliseconds — no manual mode switching needed when working across different systems.

• Simultaneous UTC and Local Time Output: The result always shows both the ISO 8601 UTC string and your browser's locale-formatted local time, so you never have to mentally subtract your UTC offset.

• Instant 'Now' Snapshot: The Now button stamps the current second as a Unix timestamp and converts it immediately — useful for generating test values, documenting when a config was set, or checking the current epoch without arithmetic.

• Bidirectional — Date to Timestamp Too: Pick any calendar date and time and get the exact Unix timestamp back in seconds, ready to paste into a curl parameter, SQL WHERE clause, or JWT exp field.

• Debug Logs and JWT Claims Quickly: Server logs and JWT payloads surface epoch integers that are unreadable at a glance. Paste them here to confirm whether a token is expired or a log event occurred in the right time window.

• Browser-Only — Works Offline and Without Sign-Up: Date arithmetic runs entirely in the browser using the native JavaScript Date API. No server, no account, and no Internet connection required once the page has loaded.

How to use

1. To convert a timestamp to a date: paste or type the Unix timestamp (seconds or milliseconds) into the 'Unix timestamp' field.
2. Click 'Timestamp → Date' — the tool outputs the ISO 8601 UTC representation and your browser's local time equivalent.
3. To convert a date to a timestamp: click the calendar icon in the 'Human date/time' field and select the date and time you need.
4. Click 'Date → Timestamp' — the output shows the corresponding Unix timestamp in seconds.
5. Click 'Now' to instantly populate the current second as a Unix timestamp and display it as a human-readable date without typing anything.
6. Copy the result from the output field — it includes both the UTC ISO string and the local time so you have both representations at once.

When it helps

• When a server log or database record shows a large integer and you need to know what date and time it represents in human terms.
• When a JWT token's exp or iat claim is an epoch integer and you need to verify whether the token is still valid or has already expired.
• When writing a curl command or SQL query with a date filter and you need the exact Unix timestamp for a specific calendar date and time.
• When a cloud API (AWS, GCP, Stripe, GitHub) returns an event timestamp as epoch seconds and you need to correlate it with a local event timeline.
• When debugging a time-based bug where two systems disagree on event ordering and you need to verify whether each system's timestamp resolves to the same instant.
• When generating test data that requires realistic past or future Unix timestamps and you need to pick a date and get the integer value quickly.

Examples

1746057600

2025-05-01T00:00:00.000Z (local: 1 May 2025, 00:00:00 in your timezone)

1715000000000

2024-05-06T20:13:20.000Z (13-digit inputs auto-detected as milliseconds)

2025-01-15 09:00 (selected via date picker)

1736931600 — paste directly into a cron trigger, SQL WHERE clause, or API parameter

Tips

• When working with JWT tokens, paste the exp claim integer directly — if the resulting date is in the past, the token has expired. The ISO 8601 output makes it immediately obvious.
• The Now button is useful for generating a stable reference timestamp at the moment a deployment starts or a config change is applied — capture it once without having to open a terminal.
• If a timestamp you got from a JavaScript application looks 1000x too large (e.g. 13 digits), it is milliseconds — the converter handles this automatically, but trim trailing zeros if you are converting to a system expecting seconds.
• To find the Unix timestamp exactly 30 days from now: click Now, note the output, then manually add 2,592,000 (30 × 86400) to the second value for a simple forward projection.
• ISO 8601 output (e.g. 2024-05-06T20:13:20.000Z) can be pasted directly into most database timestamp fields, REST API bodies, and documentation — it is universally parseable.

Frequently Asked Questions

Glossary

Unix epoch

The reference point for Unix timestamps: 00:00:00 UTC on Thursday, 1 January 1970. All Unix timestamps are the number of seconds (or milliseconds) elapsed since this moment.

Unix timestamp

An integer representing a point in time as the number of seconds elapsed since the Unix epoch. A 10-digit integer represents a date in the range 2001–2286.

ISO 8601

An international standard for representing dates and times (e.g. 2024-05-06T20:13:20.000Z). The trailing Z indicates UTC. Universally parseable by databases, APIs, and programming languages.

Millisecond timestamp

A 13-digit Unix-style timestamp counting milliseconds since the epoch. Used by JavaScript's Date.now(), Java System.currentTimeMillis(), and many cloud APIs. Divide by 1000 to get seconds.

UTC (Coordinated Universal Time)

The primary time standard against which the world's clocks are regulated. Unix timestamps always count from the UTC epoch regardless of the local timezone of the system producing them.

JWT exp claim

A field in a JSON Web Token payload that specifies the expiration time as a Unix timestamp in seconds. If exp is in the past relative to the current time, the token is expired and must be rejected.