Operator not supporting time synchronization via NITZ? Device clock lags or runs forward? There is a solution for this issue! Welcome Android application which can actually synchronize the device time with atomic time using NTP over GPRS/EDGE/3G/WiFi connection.

File Version Size Release Date
ClockSync.apk 1.2.6 246KB 26 March, 2016
TimeZoneService.apk 1.3.2 (2017c) 448KB 26 October, 2017

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ClockSync requires rooted device for automatic time synchronization, because Android system doesn't allow user applications to change system time, however you can still use rootless mode


  • Automatic and manual time synchronization (for both rooted and rootless phones)
  • Rootless mode assisted synchronization with countdown and Greenwich Time Signal
  • Displays atomic reference time, system time, clock offset and current date or last synchronization time
  • Gets atomic time from the user specified NTP server
  • Can also set time zone from the geographic location (Detect time zone)
  • System time zone override option (with fixed GTM offset and no transitions)
  • Set time zone from Olson tz database (installed separately) and perform DST/standard time transitions automatically
  • High precision synchronization/update by long tapping on the values
  • Synchronization log and statistics (average drift per day, total drift, sync count, last sync)
  • Update offset by tapping on the Local offset value on the screen
  • NTP details dialog is shown when tapping on Atomic time
  • Tapping on the system time will synchronize the device clock with the atomic clock
  • Update/Synchronize actions are also available from the application menu
  • Automatic synchronization on user specified interval (battery efficient!)
  • Options to synchronize only via Wi-Fi or when device is already awake
  • Optional Haptic feedback when tapping on the active screen elements
  • am/pm and 24-hour time display based on the system setting
  • 3 color themes: ClockSync (Default), Android (Dark), Palm Pre (Light)
  • Compatible with Android 1.5 and higher version including 4.0 and tablets



Usage notes / Known issues

  • When using Wi-Fi Only mode, clock may not sync at all as your system by default disables Wi-Fi when in sleep mode, you should either disable this option or set your Wi-Fi sleep policy to Never
  • Awake Only mode will schedule the update by the specified Interval, however the update will not occur on the interval until your device is awake by you, some other application or a call
  • 15/30 minute intervals and 1/12/24 hour intervals are battery efficient, but not precise. The system will stack up updates with other applications like Twitter, RSS, Mail, etc and perform the actions all together to save battery
  • ClockSync obeys system Background Data setting. If it's disabled, ClockSync will not perform automatic updates
  • Automatic updates performed in background may be not as precise as manual updates because of much higher latency and/or some issue with system time calculation when in background. On my device local offset drifts ~0.3s when updated automatically. I've implemented High precision mode (enabled in settings) which fully wakes the device by turning on the screen and performs 5 requests to the NTP server counting the average drift. It should help to avoid such mistakes
  • No, it's not possible to set system time without root even on FroYo (Android 2.2) where android.permission.SET_TIME was introduced, normal application can't get this permission. Vote for Android bugs: 4581 and 12497
  • System date will be displayed in the US locale, other locales may not have proper translations
  • Automatic start is the only way to set up timers after phone reboots to ensure reliable automatic synchronization, it's done according to Android guidelines. Don't blame ClockSync for this!


  • widget with offset display and one-click sync
  • GPS time support (on hold because of Android bugs 7321 and 15500)
  • Tasker/Locale plug-in


Want a new feature? Spotted a bug? Contact me!

Last modified: 2017/10/26 15:04 (external edit)