Frequently asked questions
Everything you need to know about SyncHour — the free timezone converter and meeting time finder.
What is SyncHour?
What is SyncHour?
SyncHour is a free timezone converter and meeting time finder for distributed and remote teams. You add any combination of cities or time zones, and a colour-coded slider shows you at a glance which hours overlap as working time for everyone. It runs entirely in the browser — no account, no install, no subscription required.
Who is SyncHour for?
SyncHour is built for anyone who regularly schedules meetings across time zones: remote teams, freelancers working with international clients, open-source contributors, digital nomads, and anyone coordinating between different countries. If you have ever typed "what time is 3 PM EST in London?" into a search engine, SyncHour is the tool for you.
Is SyncHour free?
Yes — SyncHour is completely free. There is no sign-up, no paywall, and no premium tier. The project is maintained by Fabio Catapano as an open utility for the global remote-work community.
Does SyncHour work on mobile?
Yes. SyncHour is a responsive web app that works on any modern browser — desktop, tablet, or smartphone. The slider supports touch drag on mobile devices, and all city cards adapt to smaller screens.
Finding the best meeting time
How do I find a meeting time that works across multiple time zones?
Add each city or time zone your team is in using the search bar at the top of the page. SyncHour then displays a 24-hour slider colour-coded by overlap quality: green segments mean everyone is in working hours (9 AM–6 PM), yellow means some people are in early or late hours, and grey means it is outside business hours for at least one location. Drag the slider to any point and the city cards update instantly to show the local time for each participant.
What does the "Best time" button do?
The "Best time" button jumps the slider to the hour where the most cities overlap within standard working hours (9 AM–6 PM). It is calculated by scoring every 15-minute interval across all selected cities and finding the peak — so it genuinely reflects the best slot for your specific combination of locations, not a generic recommendation.
What do the colours on the slider mean?
The slider is divided into 96 fifteen-minute segments, each coloured to reflect the overall meeting quality at that time. Dark green means all (or nearly all) cities are in core working hours. Light green means most cities are in working hours. Yellow means the time falls in early or late hours for at least one location (7–9 AM or 6–8 PM). Grey means it is outside business hours or sleeping time for one or more cities.
How many cities can I add?
You can add up to 10 cities at once. This covers virtually any realistic meeting scenario. You can remove cities at any time by hovering over a city card and clicking the × button.
Can I change the date to plan a future meeting?
Yes. Use the calendar button at the top of the page to select any date. This is important because UTC offsets change with Daylight Saving Time — a meeting scheduled in winter may shift by one or two hours in summer. SyncHour always calculates the correct offset for the selected date.
Sharing & copying times
How do I copy meeting times to paste into an email or Slack message?
Click the "Copy times" button at the bottom of the slider section. This copies a formatted line of text to your clipboard — for example: "📅 Mon 28 Apr — 10:00 AM London / 5:00 AM New York / 6:00 PM Tokyo". You can paste it directly into any message, calendar invite, or document.
How do I share a link to a specific meeting time?
Click "Share link" to copy a URL that encodes your exact city selection and selected time slot. Anyone who opens that link will see the same cities with the slider set to the same moment — no need to re-explain the setup. This is ideal for async teams and calendar invites.
What does the keyboard shortcut ⌘⇧C (Ctrl+Shift+C on Windows) do?
It copies the formatted meeting times to your clipboard from anywhere on the page — the same output as clicking "Copy times" — without needing to reach for the mouse. Use ← and → arrow keys to move the slider by 15 minutes, and hold Shift while pressing an arrow key to jump one hour at a time.
Time zones explained
What is UTC?
UTC (Coordinated Universal Time) is the primary international time standard used by scientists, engineers, and aviation worldwide. It is effectively the successor to GMT and does not change with Daylight Saving Time — it runs at a constant rate year-round. All other time zones are defined as offsets from UTC, such as UTC +1 (one hour ahead) or UTC −5 (five hours behind).
What is a UTC offset?
A UTC offset is the number of hours (and sometimes minutes) that a time zone differs from UTC. For example, London in summer is UTC +1 (British Summer Time), meaning local clocks are one hour ahead of UTC. New York in summer is UTC −4 (Eastern Daylight Time), meaning local clocks are four hours behind UTC. SyncHour displays the current UTC offset for each city beneath its name.
What is the difference between GMT and UTC?
In everyday usage, GMT (Greenwich Mean Time) and UTC are interchangeable — both represent the zero-offset reference point. The technical difference is that GMT is a time zone based on the position of the sun over the Greenwich meridian, while UTC is an atomic-clock-based standard that does not fluctuate. Most software and tools treat them as identical. SyncHour uses UTC internally for all calculations.
What is Daylight Saving Time (DST) and how does SyncHour handle it?
Daylight Saving Time (also called summer time) is the practice of advancing clocks by one hour during warmer months to extend evening daylight. Not all countries observe DST, and the transition dates vary by region. SyncHour uses the IANA timezone database — the same database used by all major operating systems and browsers — which automatically applies the correct DST rules for every city and every date. When you change the date, the UTC offsets update accordingly.
Why does the UTC offset for the same city sometimes change?
Because of Daylight Saving Time. For example, London is GMT (UTC +0) in winter and BST — British Summer Time (UTC +1) — in summer. New York is EST (UTC −5) in winter and EDT (UTC −4) in summer. SyncHour always shows the correct offset for the selected date, so a meeting planned in December will show different offsets than the same meeting planned in July.
Keyboard shortcuts & tips
What keyboard shortcuts does SyncHour support?
SyncHour supports the following keyboard shortcuts: ← and → arrow keys move the slider by 15 minutes; Shift + ← / → jumps by one hour; ⌘⇧C (Mac) or Ctrl+Shift+C (Windows/Linux) copies the formatted meeting times to the clipboard. These shortcuts work from anywhere on the page — you do not need to click the slider first.
Can I bookmark or save a city combination for later?
Yes. Any time you add cities, the URL updates automatically to reflect your selection — for example, ?city=London&city=New+York. You can bookmark that URL in your browser and return to the same setup instantly. Add the time parameter using "Share link" to also preserve the selected hour.