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Timezone Converter

Convert time between different UTC offsets. Enter the source time and select source and target UTC offsets to instantly see the converted time. Handles day boundary crossings.

Source Hour (0–23)

Source Minute (0–59)

Source UTC Offset

Target UTC Offset

Fill in the fields above and click Calculate to see your results.

How to use

Convert time between different UTC offsets. Enter the source time and select source and target UTC offsets to instantly see the converted time. Handles day boundary crossings.

How it's calculated

Offset Difference (hours)

target_offset - source_offset

Hour difference between source and target timezone

Raw Target Hour

source_hour + (target_offset - source_offset)

Target hour before wrapping to 0–23 range

Target Hour (0–23)

(source_hour + (target_offset - source_offset)) - floor((source_hour + (target_offset - source_offset)) / 24) * 24

Converted hour in the target timezone (wrapped to 0–23)

Target Minute

source_minute

Minutes remain unchanged during timezone conversion

Day Change

floor((source_hour + (target_offset - source_offset)) / 24)

0 = same day, 1 = next day, -1 = previous day

Examples

9:00 Vietnam (UTC+7) → UTC

Source Hour (0–23):9
Source Minute (0–59):0
Source UTC Offset:7
Target UTC Offset:0

9:00 UTC → Vietnam (UTC+7)

Source Hour (0–23):9
Source Minute (0–59):0
Source UTC Offset:0
Target UTC Offset:7

Frequently Asked Questions

How do I convert Vietnam time (UTC+7) to UTC?

Select UTC+7 as the source offset and UTC+0 as the target offset. For example, 9:00 AM Vietnam time equals 2:00 AM UTC (9 - 7 = 2).

What does 'day change' mean in the results?

Day change shows whether the converted time falls on the same day (0), the next day (+1), or the previous day (-1). For example, converting 22:00 UTC+7 to UTC gives 15:00 UTC on the same day, but converting 1:00 UTC+7 to UTC gives 18:00 UTC the previous day.

Does this calculator handle daylight saving time (DST)?

No. This calculator uses fixed UTC offsets and does not account for daylight saving time changes. For DST-aware conversions, use a dedicated world clock application or the Intl API in your browser.