Windows 10 shows time in 12-hour format (like 1:40 PM) in the US and some other regions. Switching to 24-hour time (13:40) takes a moment in Settings, and you can also change it in Control Panel for more control, including the long time format and seconds. This guide covers both methods, how the change affects the taskbar clock and apps, and how to switch back.
Quick Answer
Go to Settings > Time & Language > Region, click Change data formats, and set Short time to 13:40 (H:mm). Set Long time to 13:40:07 for seconds.
Method 1: Settings
- Press Windows + I and go to Time & Language > Region. (In some versions it’s Date & time > Date, time, & regional formatting.)
- Under Regional format data, click Change data formats.
- Under Short time, choose 13:40 (or 13:40 (HH:mm) for a leading zero like 09:05).
- Under Long time, choose the 24-hour option with seconds.
The taskbar clock updates immediately.
Method 2: Control Panel (Custom Formats)
- Open Control Panel > Clock and Region > Region (or run intl.cpl).
- On the Formats tab, set Short time to H:mm or HH:mm, and Long time to H:mm:ss or HH:mm:ss.
- For custom patterns, click Additional settings > Time and type your own format.
- Click Apply and OK.
Format Codes
| Code | Meaning | Example |
|---|---|---|
| H | Hour, 24-hour, no leading zero | 9, 13 |
| HH | Hour, 24-hour, leading zero | 09, 13 |
| h / hh | Hour, 12-hour | 1, 01 |
| mm | Minutes | 05, 40 |
| ss | Seconds | 07 |
| tt | AM/PM designator | PM |
Show Seconds on the Taskbar Clock
Windows 10 doesn’t show seconds on the taskbar by default. A registry value (ShowSecondsInSystemClock set to 1 under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced) enables it on many builds; restart Explorer afterward. Back up the registry first.
Does It Change Other Apps?
- Most apps that use Windows’ regional settings (File Explorer, Outlook, Excel’s default time format) switch to 24-hour time.
- Some apps and websites have their own time settings; check their options.
- The lock screen clock follows the same setting.
Switch Back to 12-Hour Time
Repeat the steps and choose 1:40 PM (h:mm tt) for Short time.
The same dialog handles dates too, and you can set a custom date format in Windows 10 such as yyyy-MM-dd while it is open.
Frequently Asked Questions
Does this change my time zone?
No. It only changes how time is displayed. See how to change the time on Windows 10 for time zones.
Does it work in Windows 11?
Yes, under Settings > Time & language > Language & region > Regional format. Windows 10 reached end of support on October 14, 2025.
Summary
- Settings > Time & Language > Region > Change data formats.
- Choose 13:40 for Short time.
- Use Control Panel > Region for custom HH:mm formats.
- Choose h:mm tt to go back to 12-hour time.
Kermit Matthews runs Live2Tech from just outside Philadelphia. He is an IT specialist with over 20 years of experience, from a university help desk to small-business IT, IT management and his own consulting practice, and has written tech guides full time since 2020. Steps are checked against the current software on a real device or the maker’s official documentation. More about Kermit.