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Date & time

Convert timestamps and time zones, calculate date differences, workdays, ISO weeks and durations, or generate ICS events with explicit units.

Categories

Timestamp converter

Convert integer Unix timestamps and known-offset dates, with UTC and IANA-zone display.

Integer Unix timestamp or known-offset ISO date → UTC and IANA-zone date; seconds and milliseconds

Time zones and UTC formatting

Resolve time zones and daylight-saving ambiguity, or format an instant in UTC.

Date + zones → Date

Days between dates

Find out just how far apart two dates are.

Two dates → Duration

Add or subtract dates

Add or subtract time from a chosen date.

Date + duration → Date

Stopwatch

Start a stopwatch, pause it, or record a lap.

Controls → Elapsed time

Countdown timer

Set a countdown for the task in front of you.

Duration → Countdown

Business day calculator

Add working days to a date or count a range, with optional standard US federal holidays.

Date range or start + workday count; holidays optional → Target date or workday count / JSON

ISO week number

Find an ISO week number, week-year and Monday–Sunday dates for a calendar date.

Calendar date → ISO week code / JSON

Duration calculator

Add a list of durations and subtract breaks without wrapping at 24 hours.

Duration lines (H:MM:SS / M:SS) → HH:MM:SS / TXT

Decimal hours converter

Convert a worked duration to decimal hours, or a timesheet decimal back to hours, minutes and seconds.

H:MM / decimal hours → decimal hours / HH:MM:SS / TXT

Calendar event generator

Create a timed or all-day calendar event and download an importable ICS file.

Event details → ICS

Windows FILETIME converter

Convert Windows and Active Directory FILETIME timestamps to exact UTC dates and back.

Decimal/hex FILETIME or ISO 8601 → Exact UTC / decimal / hex

ISO 8601 duration converter

Turn ISO 8601 durations into readable time and exact seconds when possible.

ISO 8601 duration → Readable time, seconds and JSON

Solar Horizon Calendar

Search every declared solar window and retain unknown, polar and invalid states with complete evidence.

UTF-8 JSON → CSV + JSON + SVG

Choose the right tool

Distinguish an instant, a calendar date and an elapsed duration. Unix units and FILETIME ticks have different epochs and scales. Enter explicit zones when needed, review daylight-saving ambiguity, and provide your own holiday list for working-day calculations.