What is Server Time / Ticketing Countdown?
Server Time requests the current timestamp returned by Clock-Tani's /api/server-time endpoint (Date.now()) three times, sorts the samples by round-trip delay, selects the middle one, and adds half that delay when estimating the offset from your device clock. If it fails, the page tries worldtimeapi.org and then timeapi.io. If every source fails on the first sync, it shows device time; after a previous successful sync, it continues an estimate using the monotonic clock and labels the stale state. The display updates in milliseconds, but an HTTP-based estimate is not a guarantee of zero error or an official time standard.
The ticketing countdown feature lets you set a target time and watch the countdown in milliseconds — perfect for concert ticket sales, course registration, limited edition purchases, and any situation where precise timing matters. When the target time arrives, a 'GO!' indicator appears with visual feedback.
Key Features
Millisecond Time Display
Uses requestAnimationFrame to show an HTTP-response-based time estimate in milliseconds. Display resolution does not guarantee millisecond accuracy.
Server Time Sync
Samples the Clock-Tani server clock three times, sorts responses by round-trip delay, uses the middle sample, and compensates for half that delay. External time APIs are tried if the first endpoint fails, and the calculated offset is shown on screen.
Ticketing Countdown
Set a target time and watch the countdown in milliseconds. 'GO!' indicator with visual feedback when the target is reached.
Copy Time
Copy the current time in HH:MM:SS.mmm format to your clipboard with one click.
Dark Mode Support
Supports both light and dark themes for comfortable use in any environment.
How to Use
- Step 1: Check Server Time — The page calculates a current-time estimate from an HTTP response and updates the display in milliseconds. Display resolution is not the same as measurement accuracy.
- Step 2: Set Target Time — Enter a time (HH:MM:SS) in your device's local time zone, or use a quick preset. There is no date input: the countdown targets the next occurrence of that time, today or tomorrow. You cannot schedule an event days away; set it on the event date, or the previous evening for a midnight opening.
- Step 3: Start Countdown — Press 'Start Countdown' to see remaining time update with millisecond display resolution.
- Step 4: Confirm GO! — When the target time arrives, 'GO!' remains on screen. Check the service's own opening notice for its actual start time and access rules.
Use Cases
Concert/Event Ticketing
Check the time remaining until an announced ticket release. Follow the seller's notice for the actual opening time and queue rules.
Course Registration
Enter an announced course registration or sign-up time in your device's local time zone and check the countdown. Confirm the site's actual opening separately.
Live Streams/Events
Check the time remaining until a scheduled live stream or limited release.
Development/Debugging
Compare your device clock with Clock-Tani's HTTP-response-based time estimate.
Frequently Asked Questions (FAQ)
How accurate is the server time?
The page queries the timestamp returned by Clock-Tani's server (Date.now()) three times, sorts the samples by round-trip delay, and applies half the delay to the middle sample. Network routes can be asymmetric and processing adds delay, so a millisecond display does not imply millisecond accuracy or zero error.
Will the countdown persist if I close the tab?
No, closing the browser tab resets the countdown. It works normally while the tab is open.
Can I check the difference between server time and my computer time?
Yes. The page shows the calculated difference between your device clock and the time estimated from an HTTP response. It is a reference offset, not a direct reading from an NTP server or national standards laboratory.
Can I use server time with an unstable internet connection?
After initial sync with the server, time is calculated locally, so brief connection issues have little impact. However, extended offline periods may cause drift, so refreshing the page is recommended.
How does time sync work?
The main page requests Clock-Tani's /api/server-time endpoint three times and corrects the middle-latency sample for round-trip delay. If that fails, it tries worldtimeapi.org and then timeapi.io. If the initial sync fails everywhere, it shows device time; after a previous successful sync, it estimates from the last anchor. Separate Korean-only per-site presets can use a target's HTTP Date header, with server and browser round-trip delays considered; the estimated offset may be reused for up to 60 seconds. The header normally has one-second resolution. If a target lookup fails, the displayed source can switch to Clock-Tani, an external time API, or device time, as indicated by the status.
Internet Time Synchronization and This Tool
Clock-Tani is not an NTP client. Its main page receives a timestamp generated with JavaScript's Date.now() by an HTTPS API, measures the request's round trip in the browser, and adds half that duration as an estimate of one-way delay. Separate Korean-only per-site presets can use the target's HTTP Date header when available, consider the server and browser round trips, and reuse the estimated target offset for up to 60 seconds. If a target lookup fails, the display can fall back to Clock-Tani, an external time API, or device time, with its source shown in the status.
Dividing a round trip in half assumes the outgoing and incoming paths have similar delays, so congestion or asymmetric routing can increase the error. HTTP Date headers also normally resolve only to whole seconds. Treat the result as a comparison and countdown aid, not as an official time distribution service or measurement instrument.
Why Your Computer Clock Drifts
Windows, macOS, Android and iOS normally provide network time synchronization, but the chosen server, schedule and correction behavior vary with device settings, management policy and connectivity. Manually changing the time or staying disconnected for a long period can also produce a difference.
Clock-Tani does not change your system clock. It applies a calculated offset from an HTTP response only to the time shown on this page. Before an important deadline, enable your operating system's automatic date and time option and verify the event time in the official service notice as well.
What to Check Before a Sale or Registration Opens
Ticket sellers and schools can change their rules for each event or registration period. Use this table as a preparation checklist, then check the current official notice for the start time, time zone, queue, and refresh rules. A displayed clock alone cannot predict queue order or whether your request will succeed.
| Situation | Check the official notice | Prepare ahead | Use this tool to |
|---|---|---|---|
| Performance or sports tickets | Confirm this sale's date, time zone, presale eligibility, queue, and refresh rules | Check the official booking route, sign-in, identity, and payment requirements | When the sale is the next occurrence of HH:MM:SS, set a reference countdown and check its time source |
| University course registration | Confirm the school's start and close times, time zone, and connection or refresh guidance | Prepare preferred and backup courses; check your school account and verification steps | Use this page as a reference; it does not query your school's server |
| Limited releases or draws | Check whether the entry is first-come or a draw, plus its window and purchase terms | Confirm the official sale link and your account, shipping, and payment details | When the release is the next occurrence of HH:MM:SS, use a reference countdown |
| Application or filing deadline | Confirm the close date, time zone, and what counts as completed submission | Prepare documents and verification; check the submitted status | Treat this clock as separate from any official receipt or filing record |
Separate Korean-only Interpark, YES24, and Melon Ticket presets use a site's HTTP Date header when it is available. The Korean-only course-registration preset does not query a particular school's server. A failed lookup can switch the displayed time source, so check its status. Clock-Tani is not affiliated with these sellers or schools and cannot verify their actual transaction time or guarantee a successful request.
Privacy Notice
This server time tool sends synchronization requests to the Clock-Tani server and may call worldtimeapi.org or timeapi.io if that fails (your IP address is exposed to those services during a request). Target time and sound preferences are saved on this device only when browser storage is available; they are not sent to the server. See the Privacy Policy for data processing by optional analytics, advertising, and other site features.