World clock
Several cities at once via Intl.DateTimeFormat timeZone—no external API.
Runs in this tab. The file stays here.
This runs in your browser. Nothing is uploaded.
About World clock
Show several cities at once using the browser IANA timezone database—no remote clock API.
This world clock stays in the tab. Nothing is uploaded to ihateonlinetools.com for the calculation. That is the same offline promise as the rest of the site: your numbers, caption, or recipe never need to sit in a third-party form log.
Each city uses Intl.DateTimeFormat with an IANA timeZone id. Daylight saving is whatever the browser database says for this instant. There is no fetch to a world-clock API and no paid timezone feed.
Add zones from the preset list or the fuller Intl.supportedValuesOf list when the engine exposes it. Remove cities you do not need. Clocks tick once a second while the tab is open. Related tools on this site cover nearby jobs without forcing a signup wall.
How to use World clock
- 1Open /date/world-clock/ and check the side-panel defaults.
- 2Enter your values or paste your list; the main pane updates.
- 3Copy the result if you need it elsewhere. Closing the tab clears local state unless noted.
What it won't do
- Not professional advice and not a hosted account product.
- Garbage in, garbage out: wrong inputs yield wrong outputs.
Common questions
Does world clock upload anything?
No. Inputs and outputs stay in the browser process. Sharing features that exist, such as countdown links, only put values you choose into the URL on your device.
What formula or method does world clock use?
Each city uses Intl.DateTimeFormat with an IANA timeZone id. Daylight saving is whatever the browser database says for this instant. There is no fetch to a world-clock API and no paid timezone feed.
When should I not rely on world clock alone?
When a clinician, building code, platform policy, or teacher requires a signed process. This page is a calculator and explainer, not a certificate.
Is world clock free and offline-capable?
Yes. After the static page loads, the logic runs without calling an external compute API. Return visits may use the service worker cache for the shell.
Related tools
Why this one doesn't upload your file
There is no server to upload to. This page is a static file, and the work happens in your browser using the same graphics and WebAssembly code that renders every other site you visit. Your file is read from disk into memory, processed, and handed back as a download. Once the page has loaded you can disconnect from the network entirely and it keeps working. The longer explanation