What time is it in Seoul when it's 9 AM in Denver?

12:00 AM (next day) — as of 3 October 2026. Seoul is 15 hours ahead of Denver.

Does the time difference between Denver and Seoul change?

Yes. In 2026 it's 16 hours or 15 hours, depending on the date, because only Denver changes its clocks.

What's the best time for a call between Denver and Seoul?

There's no hour when both cities are in working hours (09:00–17:00). The fairest is around 16:00 in Denver (07:00 in Seoul).

What time zones are Denver and Seoul in?

Denver uses America/Denver (UTC−6 today); Seoul uses Asia/Seoul (UTC+9 today).

Time difference between Denver and Seoul

Seoul is 15 hours ahead of Denver. When it's 9:00 in Denver, it's 00:00 (next day) in Seoul.

From

Seoul is 15 hours ahead of Denver.

On Saturday, 3 October 2026, 09:00 in Denver is 00:00 (next day) in Seoul. Denver is UTC−6; Seoul is UTC+9.

The gap through 2026

1 Jan – 8 MarSeoul is 16 hours ahead of Denver.
8 Mar – 1 NovSeoul is 15 hours ahead of Denver.
1 Nov – 31 DecSeoul is 16 hours ahead of Denver.

Denver moves its clocks forward on 8 March (UTC−7 → UTC−6).
Denver moves its clocks back on 1 November (UTC−6 → UTC−7).

Denver to Seoul, hour by hour

On Monday 5 October.

Denver	Seoul
07:00 Early morning	22:00 Sleeping hours
08:00 Early morning	23:00 Sleeping hours
09:00 Working hours	00:00+1 Sleeping hours
10:00 Working hours	01:00+1 Sleeping hours
11:00 Working hours	02:00+1 Sleeping hours
12:00 Working hours	03:00+1 Sleeping hours
13:00 Working hours	04:00+1 Sleeping hours
14:00 Working hours	05:00+1 Sleeping hours
15:00 Working hours	06:00+1 Sleeping hours
16:00 Working hours	07:00+1 Early morning
17:00 Evening	08:00+1 Early morning
18:00 Evening	09:00+1 Working hours
19:00 Evening	10:00+1 Working hours
20:00 Evening	11:00+1 Working hours
21:00 Evening	12:00+1 Working hours
22:00 Sleeping hours	13:00+1 Working hours

Daylight saving in 2026

Denver moves its clocks forward on Sunday 8 March (UTC−7 → UTC−6).
Denver moves its clocks back on Sunday 1 November (UTC−6 → UTC−7).

1 Jan – 8 MarSeoul is 16 hours ahead of Denver.
8 Mar – 1 NovSeoul is 15 hours ahead of Denver.
1 Nov – 31 DecSeoul is 16 hours ahead of Denver.

Best times for a call

Working hours (09:00–17:00) in Denver and Seoul don't overlap, so any call is early or late for someone.

Denver 16:00Working hoursSeoul 07:00 +1Early morning
Denver 18:00EveningSeoul 09:00 +1Working hours
Denver 19:00EveningSeoul 10:00 +1Working hours

How the time difference calculator works

The difference is each city's offset from UTC on the date you pick, subtracted. Offsets come from the IANA time zone database in your browser.

Because countries change their clocks on different dates — or not at all — the gap between two cities can change for a few weeks a year. The calculator lists every change in the year.

Examples

London is 5 hours ahead of New York for most of the year, but only 4 hours ahead for about three weeks in March and one week in late October.
Dubai doesn't change its clocks, so its gap to London is 4 hours in winter and 3 hours in summer.

Good for

Knowing when a colleague's day starts
Setting expectations for replies across time zones
Planning travel and jet lag

Frequently asked questions

What time is it in Seoul when it's 9 AM in Denver?: 12:00 AM (next day) — as of 3 October 2026. Seoul is 15 hours ahead of Denver.
Does the time difference between Denver and Seoul change?: Yes. In 2026 it's 16 hours or 15 hours, depending on the date, because only Denver changes its clocks.
What's the best time for a call between Denver and Seoul?: There's no hour when both cities are in working hours (09:00–17:00). The fairest is around 16:00 in Denver (07:00 in Seoul).
What time zones are Denver and Seoul in?: Denver uses America/Denver (UTC−6 today); Seoul uses Asia/Seoul (UTC+9 today).

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