About DateTime

DateTime is a working set of small calculators for time-of-day, calendar-date, duration, and timezone arithmetic. The audience is the mixed group of people who actually do this math at 11pm in a different time zone: a developer scheduling a Discord-timestamp tag for a launch, a recruiter coordinating an on-site across three continents, a project manager counting business days until a contractual deadline, a parent figuring out an exact age in days for a forms upload. Each tool answers one calendar question and shows the underlying inputs so the math is verifiable.

The tool list

The cluster includes a timezone converter built on the IANA tzdb identifiers (not abbreviations like “EST” — those are ambiguous between Eastern Standard Time and Australian Eastern Standard Time), a stopwatch and countdown, an age calculator with day-level precision, days-until and date-add calculators, business-hours and working-days math (with weekend and holiday awareness for a few common calendars), a Unix-timestamp converter, and a Discord-timestamp tag builder for moderators who want messages to render in the reader’s local time.

Why IANA matters

Timezone abbreviations are a trap. “CST” can mean Central Standard Time (Chicago), China Standard Time (Shanghai), or Cuba Standard Time depending on context. “BST” can mean British Summer Time or Bangladesh Standard Time. DateTime uses IANA zone identifiers (America/New_York, Europe/London, Asia/Tokyo) which encode region history including DST transitions and historical offset changes. When daylight saving rules shift — as they have in Egypt, Iran, Mexico, and several US territories over the last decade — the tools pick up the change automatically when the bundled tzdb release is updated.

Editorial cadence

DateTime is published by the inovisum team, a small tools studio. The bundled tzdb release and the holiday calendars used by the working-days tool are reviewed on each release pass; new tzdb releases (typically two to four per year) are picked up within a week of publication. If a tool returns a value that disagrees with the tzdb release you have installed on your own system, write in with the IANA zone and the UTC offset you expected — the page will be re-checked against the cited release.