UnixTime · Students & Educators

Understand Unix time with a concrete date.

A number makes more sense when you can see its date. Compare time and date formats on your Mac and create your own examples for exercises and teaching.

Understand Unix timestamps: convert and compare seconds, milliseconds, microseconds and nanoseconds without rounding.

See how it works ↓

macOS 14.6+ · One-time purchase · Local to your Mac

OfflinePrivacy without uploadsNo account requiredOn all your Macs

Sound familiar?

Less friction when working with time.

Seconds and milliseconds get confused

Compare 1790812800 seconds with 1790812800000 milliseconds: they describe the same instant.

Time zones make the display unfamiliar

Look at UTC and local date representations. The display changes; the instant stays the same.

Your own examples are easier to remember

Choose a date in the generator and copy its time values into your exercise notes.

Your next time value

Three steps to a readable result.

Choose an instant
Set the generator to 1 October 2026 at 00:00:00 UTC.
Compare representations
Look at the Unix value in seconds and milliseconds alongside the readable UTC date.
Convert back
Copy the numeric time value and convert it back to a date with the menu bar icon or ⌘⌃U.

The example uses UTC. Your output follows your selected default formats. Direct insertion via a shortcut requires macOS Accessibility permission.

Formats and keyboard shortcuts explained →

UnixTime on Mac: Set the date, time zone and time offset in the date generator. — Set the date, time zone and time offset in the date generator. App screenshot; values may differ from the example.

Precision for log analysis & forensics

Does not round. Down to the nanosecond.

Convert Unix timestamps with nanosecond precision. UnixTime preserves fractional seconds from numeric input timestamps. No floating-point rounding. No zeros recreated from whole seconds.

17908128001234567892026-10-01 00:00:00.123456789 UTC

Example: Unix nanoseconds, a custom date format and the UTC time zone. Source accuracy still matters; conversion does not invent extra measurement precision.

Custom formats: 3, 6 or 9 digits.

Pattern	Display precision	Example
`SSS`	Milliseconds (3 digits)	`.123`
`SSSSSS`	Microseconds (6 digits)	`.123456`
`SSSSSSSSS`	Nanoseconds (9 digits)	`.123456789`

Use, for example yyyy-MM-dd HH:mm:ss.SSSSSSSSS. Nine digits display the full nanosecond fraction. Three or six display only the leading digits, without rounding up. A pattern without S does not display fractional seconds.

Keyboard shortcuts on your Mac

Keep typing. Your timestamp is ready.

Copy your time value and click the menu bar icon — or press ⌘⌃U. Reassign any of the four shortcuts to suit your workflow.

⌘⌃U: Convert the clipboard
⌘⌃V: Convert and replace your selection
⌘⌃⌥V: Append the conversion to the original
⌘⌃N: Insert the current timestamp

⌘ = Command · ⌃ = Control · ⌥ = Option. Inserting, replacing and appending text require macOS Accessibility permission and an editable text field. Clipboard conversion does not require that permission.

Keyboard shortcuts explained →

UnixTime settings: four global keyboard shortcuts and custom separators for appended results — Your shortcuts, your separators. Customise them in Settings.

Before you start

Your questions, answered.

Is a timestamp a local time?

A Unix timestamp counts elapsed time from the Unix epoch. The time zone determines how that instant is displayed as a calendar date and clock time.

Is UnixTime a course?

No. The app is a practical tool for creating and checking examples. You can also find explanations of the formats in the help section on this website.

How do I display fractional seconds?

Use a custom date format: SSS for milliseconds (3 digits), SSSSSS for microseconds (6 digits), or SSSSSSSSS for nanoseconds (9 digits). Choose nine digits to display all available nanoseconds. Shorter patterns show only the leading digits, without rounding up.

What do I need to use keyboard shortcuts?

UnixTime must be running on your Mac. All shortcuts can be reassigned. Replacing, inserting and appending text require macOS Accessibility permission and an editable destination. Converting the clipboard with the menu bar icon or ⌘⌃U does not require that permission. ⌘ means Command, ⌃ means Control and ⌥ means Option (Alt).

Does it work offline?

Yes. Conversion, the date generator and history run locally. They need neither an account nor an internet connection. UnixTime is a one-time purchase without a subscription; see the Mac App Store for the current price.

For your next timestamp