Date Duration
Days between dates, inclusive/exclusive.
Time & Date
Do precise date math, convert time zones, find ISO week numbers and work with Unix time — fast and clutter-free.
Who this hub is for
Project managers, developers, operations teams and anyone wrangling schedules across countries. Use the featured cards, comparison table and worked examples to jump straight to the right tool.
Note: Time zones and daylight saving rules vary by location and change over time. For legal or regulatory deadlines, confirm results with official sources.
Best Time & Date Tools (Quick Picks)
Compare Tools
| Tool | Best For | Inputs | Outputs | |
|---|---|---|---|---|
| Date Duration | Project timelines & gaps | Start date, end date, inclusive? | Days, weeks; optional breakdown | Open |
| Time Zone Converter | Cross-country meetings | Source time, cities/zones, date | Local times with DST | Open |
| Day & Week Number | Planning sprints | Date (or today) | ISO week, day-of-year | Open |
| Epoch/Unix Time | APIs & logging | Date/time, seconds or ms | Unix epoch ↔ human time (UTC) | Open |
| Time Unit Converter | Quick time math | Value & unit | sec, min, hr, day… | Open |
| Age Calculator | Exact age today / on date | Birth date, reference date | Years, months, days | Open |
| Time Card Calculator | Timesheet totals | In/Out times, breaks | Total hours, overtime | Open |
Date Calculations
- Date Duration — days/weeks between two dates.
- Age Calculator — age today or on a reference date.
- Day & Week Number — ISO week, day-of-year.
Time Zones & Clocks
- Time Zone Converter — city-aware with DST changes.
- Epoch/Unix Time — human ↔ seconds/milliseconds (UTC).
Formats & Conversions
- Time Unit Converter — seconds, minutes, hours, days.
- Need ISO formatting tips? See the sidebar below (ISO-8601).
Work & Scheduling
- Time Card Calculator — totals for timesheets.
- For pay math, see Work Hours & Overtime (Finance hub).
Worked Examples
- Project gap: Start 2025-01-12, end 2025-04-05 → use Date Duration. Toggle inclusive to count both endpoints.
- Global stand-up: 09:30 Berlin on 2025-03-31 → in Time Zone, add New York & Singapore and confirm offsets post-DST.
- Unix timestamp: Convert 1731868800 seconds to human time in Epoch (UTC), then localize if needed.
Frequently Asked Questions
Does Date Duration count the end date?
Choose inclusive to count both start and end; exclusive omits the start by default.
How are ISO week numbers defined?
ISO week 1 has the year’s first Thursday; weeks start Monday.
Will DST changes affect time-zone results?
Yes. Always set the correct date and city to account for DST rules.
UTC vs GMT?
Use UTC for calculations; GMT is a time zone historically aligned with UTC.
What is Unix epoch time?
Seconds (or ms) since 1970-01-01 00:00:00 UTC, ignoring leap seconds.
Why 52 or 53 ISO weeks?
Calendar alignment can yield 52 or 53 weeks in a year.
12/24-hour format tips?
Prefer 24-hour for clarity; if 12-hour, add AM/PM and time zone.
Leap year handling?
Tools use calendar-aware math including leap years and Feb 29.
Adding months safely?
Month addition clamps to valid days (e.g., Jan 31 → Feb 28/29).
Legal deadlines?
Use these tools as guidance; verify with official calendars/authorities.
Time & Date Disclaimer
Results are based on standard calendars and time-zone rules. Because governments update DST/offset policies, confirm critical schedules with official sources or system clocks.
- DST & historical data: Offsets can change by city and year.
- Precision: Prefer 24-hour times and include the time zone (e.g., “2025-05-12 16:30 UTC+2”).
- Legal & compliance: For court, tax or regulatory deadlines, use official calendars.
- Privacy: Calculations run in your browser; inputs aren’t stored. See Legal & Privacy.
Related Hubs
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