About the World Clock Calculator
What is the World Clock Calculator?
This world clock converts one moment into local times across more than 25 cities and time zones.
Each city is marked as in business hours, off hours or night, to help you pick when to call.
How to use the World Clock Calculator
- Date and Time (sample: 2026-10-23T00:17)
- Your Time Zone (sample: India – IST)
- Highlight City (sample: London)
- Press Show World Times (results also refresh as you type). The result card shows the Time in Selected City, along with Selected city offset and Your time.
Formula used
Local time = UTC time + City's UTC offset (including daylight saving)
Worked example
These are the sample values already filled in the calculator above, and the result it returns for them:
| Input | Sample value |
|---|---|
| Date and Time | 2026-10-23T00:17 |
| Your Time Zone | India – IST |
| Highlight City | London |
| Result | Value |
|---|---|
| Time in Selected City | Thu, 22 Oct 2026, 07:47 PM |
| Selected city offset | UTC+01:00 |
| Your time | Fri, 23 Oct 2026, 12:17 AM (UTC+05:30) |
Tips for using the World Clock Calculator
- Business hours are taken as 9 AM–6 PM, Monday to Friday, local time.
- Gulf countries have no daylight saving; the US, UK, Europe and Australia do.