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Time Zone Calculator

Convert a dated local clock time between IANA time zones and handle daylight-saving gaps or repeats.

Your numbers

Make it your own
Updates as you type
Local date and time in Europe/Kyiv
2026-10-24 19:00:00

Calculated from your inputs · rounded for display

UTC instant2026-10-24T16:00:00.000Z
Source UTC offset-4hours
Destination UTC offset3hours
Source occurrenceUnambiguous

Uses the runtime’s IANA time-zone database. Future legislation may change offsets. Calendar gaps are rejected; repeated times use your explicit occurrence choice.

Your calculation, step by step

No black boxes
  1. Resolve the entered wall-clock time against IANA zone rules for that date.
  2. Convert the chosen instant to the destination zone; the date may change.

How to use this calculator

  1. Enter your own values in the labeled fields. Check the units and assumptions before comparing results. Only the fields needed for your selected calculation mode are shown.
  2. Your answer updates automatically. Review the calculation steps to see exactly how it was calculated.
  3. Copy, share, save, or download your result. Saved inputs stay on this device.

How the calculation works

Source wall time + IANA rules → UTC instant → destination wall time

Use an IANA name such as Europe/Kyiv, not a fixed abbreviation like CST. Rules are evaluated on the entered date. Nonexistent spring-forward times are rejected; repeated fall-back times require a chosen occurrence. Supported years are 2000–2100. Review the units, period and assumptions before comparing scenarios. Displayed values are rounded, while the underlying calculation retains its available precision.

A worked example

On January 15, 2026, 12:00 in America/New_York is 17:00 UTC. A spring-forward time such as March 8, 2026 at 02:30 in that zone does not exist.

Reading your result

Use the main result together with its units and supporting figures. Display values are rounded; calculations keep their underlying precision. A change in inputs or assumptions can change the answer. Compare the step-by-step working with your intended use before relying on an estimate.

Frequently asked questions

What assumptions does this calculation use?

Use an IANA name such as Europe/Kyiv, not a fixed abbreviation like CST. Rules are evaluated on the entered date. Nonexistent spring-forward times are rejected; repeated fall-back times require a chosen occurrence. Supported years are 2000–2100.

Can I save or check a scenario?

The result includes the working and supporting values. Save and Restore keep inputs on this device; Copy, Download and Print export the result. Sharing a scenario explicitly includes the inputs in its link.

Sources & methodology

This calculator uses the mathematical identity and assumptions stated above. No current rates, prices, or external data are loaded. Conversion tools use international unit definitions.

Formula review: October 24, 2026. Read our methodology.