CalcaTools

Time Zone Converter | Convert Between Major World Time Zones

Convert times between any time zones with daylight saving applied automatically, and find meeting times across regions. The remote-team essential — enter the time and zones and get everyone's local time.

Last updated: June 2026 · Free · No sign-up required

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Quick reference

12:00 New York (EDT)Equals
London17:00
Dubai20:00
Delhi21:30
Singapore00:00 (+1 day)
Sydney02:00 (+1 day)

info Time Zone Converter

Free converters calculator — enter your numbers and get an instant, accurate result.

info Private by design

Everything runs locally in your browser. No uploads, no accounts, no tracking.

info Works everywhere

Fully responsive and mobile-friendly — calculate on any device, any time.

info Educational

Includes the formula and step-by-step explanation so you understand the math, not just the answer.

Interpretation guide

Meeting windowCoverage
13:00–16:00 UTCUS East morning + Europe afternoon
06:00–08:00 UTCEurope morning + Asia afternoon
22:00–00:00 UTCUS West afternoon + Asia-Pacific morning

lightbulb Worked example

Let's say you are using the Time Zone Converter. A free tool to convert time between major world time zones. Essential for remote teams, international meetings, and global business scheduling. Enter the values that match your situation into the input fields and press calculate — using realistic numbers makes the result directly useful for you.

Result: The calculator instantly applies the formula Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules) and returns the result with appropriate precision.

What this means: Read the result in the context of what you are measuring. The step-by-step breakdown lets you confirm the math and understand which input most affects the outcome.

Formula & methodology

Formula: Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules)

The Time Zone Converter is built on a well-established calculation method. It uses the formula Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules) to turn your inputs into a reliable result. A free tool to convert time between major world time zones. Essential for remote teams, international meetings, and global business scheduling. The steps are shown on the page so you can follow the reasoning from input to output.

  1. Pick the source city/zone and a date-time.
  2. The converter applies each zone’s current UTC offset — including daylight-saving rules for that specific date.
  3. All selected cities display the local equivalent, flagging day changes.

Worked example: 12:00 in New York (summer, EDT = UTC−4) is 17:00 London, 21:30 Delhi and 02:00 next-day Sydney — note India’s half-hour offset and the date line’s +1 day.

Authoritative source: U.S. National Institute of Standards and Technology

Frequently asked questions

How do I convert time between zones manually?
Enter the required values into the input fields and press the calculate button. The tool applies the formula Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules) and returns the result with a short explanation of each step, so you can check the working yourself.
Why do conversions change twice a year?
Because regions observe daylight saving time, their UTC offsets shift twice a year — typically +1 hour in spring and back in autumn. The conversion Target time = source time − source UTC offset + target UTC offset is applied with each zone's DST rules, so the same source time can convert differently depending on the date. The calculator uses the correct offset for the date you select.
Which zones have half-hour offsets?
The Time Zone Converter is free, private, and accurate: it runs entirely in your browser (no uploads, no accounts), applies the standard calculation, and explains each step so you can verify the result. A free tool to convert time between major world time zones. Essential for remote teams, international meetings, and global business scheduling. There is no limit on usage, and it works on any device.
How do I find a meeting time for 3 continents?
Convert the meeting time to UTC first, then convert UTC to each participant's local zone: target = source time − source offset + target offset. With DST applied per zone, the offsets change seasonally. The converter displays the same instant across all selected zones, so you can scan for an hour where everyone's day overlaps — typically morning in the Americas, afternoon in Europe, evening in Asia.
Whats the difference between GMT and UTC?
Functionally none for timekeeping — UTC is the modern atomic-time standard and GMT is the historical solar-time reference; both use the same clock and offset of +00:00. The technical difference is precision: UTC is defined by atomic clocks with leap seconds, while GMT was based on the sun's position at Greenwich. For time-zone conversion they are interchangeable.
What does the Time Zone Converter do?
A free tool to convert time between major world time zones. Essential for remote teams, international meetings, and global business scheduling. The calculator takes your inputs, applies the standard calculation, and returns a clear result so you can make an informed decision without doing the math by hand.
What formula does the Time Zone Converter use?
The Time Zone Converter applies the standard formula: Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules). The tool walks through each step of the calculation so you can verify the numbers yourself.
Is the Time Zone Converter free and private?
Yes — the Time Zone Converter. There is no sign-up, no paywall, no trial, and no limit on how many calculations you can run. CalcaTools covers its costs with non-intrusive display advertising, so the calculator itself never asks for payment or restricts any feature.
How accurate is the Time Zone Converter?
The Time Zone Converter applies the standard formula: Target time = source time − source UTC offset + target UTC offset (DST applied per zone rules). It is tested against published worked examples before launch and uses native double-precision arithmetic, so results are accurate to typical precision for the values you enter — with no intermediate rounding that could distort the answer.

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