Everything You Need to
Master Timezones
ClockinSync is a browser extension built for remote and global teams. It handles every timezone edge case, from DST surprises to public holidays in 100+ countries, so you can focus on the actual work.
See Them Working Live
Every demo below is interactive and pulling real-time data. This is exactly what the extension shows you every day.
ClockinSync cross-references your city list against a database of public holidays for 100+ countries. You get an amber warning 7 days in advance and a red alert on the day itself right on the city card, impossible to miss.
Clock changes silently break recurring meetings. ClockinSync detects every upcoming DST shift for every city in your list and counts down 7 days in advance. On the day it shows the direction (forward/back) and exact time.
ClockinSync scans every page for timezone strings like "3pm EST" or "10:00 PST" and underlines them in purple. Hover any one to see a tooltip with instant conversions for your entire saved city list, no copy-paste, no mental arithmetic.
In any text field across Teams, Slack, Gmail, Notion, or Google Docs, type /time followed by a time and city. A results picker appears with your team's local times, click any row to paste it directly into your message.
Set reminders in any timezone with a full date + time picker, five recurrence options, and configurable pre-alerts. ClockinSync adjusts automatically when clocks change, "9am London every Monday" always fires at the right local time, even after a DST transition.
Never Catch a City Off Guard
ClockinSync checks public holidays for every city in your list, a yellow 7-day heads-up and a red alert on the actual day, right on each city card. No more accidentally scheduling a meeting on a national holiday.
- Amber warning 7 days ahead, time to reschedule
- Red alert on the holiday itself, impossible to miss
- Covers 100+ countries, refreshed annually
Daylight Saving, Handled
DST shifts silently break recurring meetings. ClockinSync detects upcoming clock changes for every city in your list and warns you with a 7-day countdown, so you can adjust before the chaos hits.
- Amber warning up to 7 days before the clock change
- Red alert on the day itself, direction and exact time shown
- Works for every IANA timezone or city, automatically, zero config
Times on Any Page, Converted Instantly
ClockinSync scans every webpage for timezone references like "3pm EST" and underlines them in purple. Hover to see instant conversions for your entire team, no copy-pasting, no mental math.
- Detects times in emails, Teams, Slack, Notion, Google Docs etc.
- Shows all your saved cities converted in one hover
- Green dot = in working hours · Red dot = outside working hours
Hi team, weekly standup is at 3pm EST on Friday. Client presentation at 10am PST Thursday. See you then!
Convert Any Time While You Type
In any text field - Teams, Slack, Gmail, Notion, Google Docs, type /time followed by a time and city to see instant conversions for your whole team.
- /time now - current time across all your cities
- /time 3pm Tokyo or /time 15:25 London convert instantly
- Click a result to paste the formatted time into your text field
Never Miss a Meeting Across Timezones
Set meeting reminders in any timezone with a full date picker, clock, and recurrence options. ClockinSync handles DST adjustments automatically, so "9am London every Monday" always rings at the right local time.
- Full date + time picker, no manual UTC math
- Recurring: once, daily, weekdays, weekly, monthly
- Pre-alerts: get a 10m, 15m, or 1h heads-up
- DST-aware, reminders stay correct after clocks change
Every Detail, Covered
Beyond the five headline features, ClockinSync handles the smaller things that make a big difference in day-to-day use.
Toolbar Popup
Click the ClockinSync icon in your browser toolbar and your entire city list appears in under 50 ms, live times, day/night indicators, and working-hours dots at a glance.
Named Profiles
Save different city sets as named profiles, Work, Clients, Team, Personal. Switch between them in one click to see only the cities that matter right now.
Working Hours Overlap
A colour-coded overlap bar across your team's cards shows instantly when everyone is online at the same time, stop the back-and-forth Teams or Slack messages finding a slot.
Natural Language Bar
Type 3pm London or 15 or 15:27 London or any of the 23000+ cities in the Search Bar of extension and get an instant conversion to your base time without opening a new tab or leaving your current workflow.
Work and OOO Indicator
Each city card shows a green dot (working time) or red dot (out of office) updated in real time. Know at a glance whether it's a reasonable hour before pinging that colleague.
Privacy First
ClockinSync runs entirely in your browser. No account required for Free plan, no private data sent to our servers, no third-party tracking scripts. Your city list and settings never leave your device.
Dark & Light Mode
Automatically matches your OS appearance setting, or toggle it manually. The popup, tooltips, and every UI element look great in both themes.
Clipboard Detection
Copy a time expression like "3:30 PM EST" from anywhere on your screen. ClockinSync detects it and immediately offers a one-click conversion across all your saved cities.
23000+ City Search
Add any city in the world using the built-in search, backed by the full IANA timezone database. If it has a timezone, you can track it.
Up and running in 60 seconds
No account needed for Free users. No configuration. Just install and add your cities.
Install in seconds
Add ClockinSync from the Chrome Web Store, Edge Add-ons, or Firefox AMO. No sign-up required, no permissions beyond your active tab.
Build your city list
Search for any city in the world and pin it to your list. Organise into named profiles, Work, Clients, Team, Personal and switch between them with one click.
Work without friction
Live times in the popup, holiday & DST alerts on every card, /time shortcodes while you type in any app, and meeting reminders that stay accurate through every DST change.
Works in Your Browser
One extension, three browsers, your city list and settings stay consistent wherever you work.
Ready to stop juggling timezones?
Install ClockinSync free today, no account for free users, no credit card, works in Chrome, Edge and Firefox.
Free forever plan · Available for Chrome, Edge & Firefox · 5 stars