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For humans, not crontabs.\n\n```\n$ tzdiff IDT PST UTC TYO\nidt      tue 14:30  apr 28  +0300\npst      tue 04:30  apr 28  -0700\nutc      tue 11:30  apr 28  +0000\ntyo      tue 20:30  apr 28  +0900\n```\n\n## Why tzdiff\n\nScheduling a sync between Tel Aviv, San Francisco, and Tokyo in your head is a tax. The website-based timezone converters take two clicks per zone and break in incognito because they want your localStorage. Your terminal already knows the right answer; it just doesn't print it in a comparable shape. `dig` for DNS, `tzdiff` for time.\n\n## Install\n\n```bash\nnpm install -g @v0idd0/tzdiff\n```\n\n## Usage\n\n```bash\n# Current time in multiple zones\ntzdiff IDT PST UTC TYO\n\n# Use IANA names too\ntzdiff Asia/Tokyo Europe/London America/New_York\n\n# Specific moment in time\ntzdiff --at \"2026-04-28 09:00 UTC\" PST EST IST\n\n# JSON for scripting\ntzdiff --json UTC IDT TYO | jq '.[] | .time'\n```\n\n## Supported aliases\n\n**Americas:** PST, PDT, MST, MDT, CST, CDT, EST, EDT, AKST, HST\n**Europe:** GMT, UTC, BST, CET, CEST, EET, EEST, MSK\n**Middle East:** IDT, GST, AST\n**Asia:** IST (India), PKT, ICT, WIB, HKT, SGT, JST, TYO, KST\n**Oceania:** AEDT, AEST, SYD, ACDT, AWST, NZDT, NZST\n\nAnything else → use the IANA name directly (`America/Sao_Paulo`, `Africa/Cairo`, etc.).\n\n## Compared to alternatives\n\n| tool | offline? | DST aware | output for grep/Slack | install |\n|---|---|---|---|---|\n| tzdiff | yes | yes (via Intl/IANA) | yes, aligned columns | one npm install |\n| `date -u` chains | yes | partially | requires shell-fu | bundled with OS |\n| World Time Buddy / time.is | no | yes | screenshot only | web |\n| `tz` (older CLI) | yes | yes | column drift | unmaintained |\n\nTools like timeanddate.com handle the broader case (recurring meetings, DST historical lookups). `tzdiff` is the speed-of-typing case: you have 4 abbreviations in your head and want a 4-row answer in 200ms.\n\n## FAQ\n\n**Why \"IST\" defaults to India and not Israel?** Because India is +0530 year-round and Israel toggles between IST/IDT seasonally. We default IST to India to avoid quietly changing meaning twice a year. For Israel use `IDT` (summer) or `Asia/Jerusalem`.\n\n**Does `--at` accept your home timezone?** Pass it explicitly: `--at \"2026-07-31 17:00 PDT\"`. The parser accepts `\u003cdatetime\u003e \u003ctz\u003e` in that order.\n\n**Will it ever DST-jump output rows?** Each row is computed independently against its zone's TZ database, so yes — running on the spring-forward Sunday will show the forward jump in the affected zone only.\n\n**Can I save a recurring meeting?** No. tzdiff is one-shot by design. For recurring time-math, use a calendar app — that's a different problem.\n\n## Programmatic API\n\n```javascript\nimport { compare, format } from '@v0idd0/tzdiff';\n\nconst rows = compare(['UTC', 'IDT', 'TYO']);\nconsole.log(format(rows));\n\n// Or with a specific moment:\nconst at = new Date('2026-07-31T17:00:00Z');\nconst rows = compare(['PST', 'IDT'], at);\n```\n\n## Tips for meeting math\n\n- **Pin one zone as your anchor.** When scheduling, write the time once in UTC and let recipients run `tzdiff --at \"2026-05-12 14:00 UTC\" \u003ctheir zone\u003e` — eliminates the \"is that 2pm yours or mine\" thread.\n- **DST-sensitive ranges.** If a meeting falls within a few weeks of a DST boundary, run tzdiff for both pre- and post-boundary dates; the zones won't always agree on which week the change lands.\n- **Slack format.** The aligned columnar output pastes cleanly into Slack code blocks (`\\`\\`\\``) — no Markdown table conversion needed.\n\n## More from the studio\n\nThis is one tool out of many — see [`from-the-studio.md`](from-the-studio.md) for the full lineup of vøiddo products (other CLI tools, browser extensions, the studio's flagship products and games).\n\n## From the same studio\n\n- **[@v0idd0/jsonyo](https://www.npmjs.com/package/@v0idd0/jsonyo)** — JSON swiss army knife, 18 commands, zero limits\n- **[@v0idd0/envguard](https://www.npmjs.com/package/@v0idd0/envguard)** — stop shipping `.env` drift to staging\n- **[@v0idd0/depcheck](https://www.npmjs.com/package/@v0idd0/depcheck)** — find unused dependencies in one command\n- **[@v0idd0/gitstats](https://www.npmjs.com/package/@v0idd0/gitstats)** — git repo analytics, one command\n- **[View all tools →](https://voiddo.com/tools/)**\n\n## License\n\nMIT.\n\n---\n\nBuilt by [vøiddo](https://voiddo.com/) — a small studio shipping AI-flavoured products, free dev tools, Chrome extensions and weird browser games.\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fvoidd0%2Ftzdiff","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fvoidd0%2Ftzdiff","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fvoidd0%2Ftzdiff/lists"}