Google Calendar, Outlook, Apple Calendar — none of them can show you when a group across timezones is free before you propose a time. Dedicated tools like Calendly and Doodle don't solve it either. thyme.works does.
| Feature | thyme.works | World Time Buddy | Calendly | Doodle | SavvyCal | Cal.com |
|---|---|---|---|---|---|---|
| Timezone heatmap (visual overlap) | ✓ | ✓ | — | — | — | — |
| DST handled automatically | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Public holiday overlay | ✓ | — | — | — | — | — |
| Real calendar free/busy scanning | ✓ | — | ✓ | — | ✓ | ✓ |
| Google Calendar RSVP invites | ✓ | — | ✓ | — | ✓ | ✓ |
| Attendees need no account | ✓ | — | ✓ | ✓ | ✓ | ✓ |
| AI smart time suggestions | ✓ | — | — | — | — | — |
| Natural language scheduling | ✓ | — | — | — | — | — |
| Zoom / Teams / Webex integration | ✓ | — | ✓ | — | ✓ | ✓ |
| Meeting analytics | ✓ | — | ✓ | — | — | ✓ |
| Open source | — | — | — | — | — | ✓ |
| Pricing starts at | Free | Free / $4.99 | Free / $10 | Free / $6.95 | $12 / month | Free (self-host) / $12 |
World Time Buddy is the go-to for quickly checking what time it is in another city. It has a clean overlap view and a basic scheduler. What it doesn't do: scan real calendars, send invites, or touch AI. If your workflow stops at 'find the overlap window and copy-paste the time into an email', WTB is fine. The moment you need to confirm actual availability rather than assumed working hours, it can't help.
Calendly solved a real problem: letting people book time with you without the back-and-forth. But it's fundamentally a one-sided tool — it shows the organiser's availability and asks the guest to pick. Multi-party scheduling (three people in different timezones finding a slot that works for all) requires round-robin workarounds that feel bolted on. The visual timezone overlap view that thyme.works is built around doesn't exist in Calendly.
Doodle is the oldest approach: propose several slots, ask everyone to vote on which works. It's surprisingly effective for large groups where finding a single perfect slot is impossible. The tradeoff is friction — you propose, they vote, you reconcile, you book, you send the invite manually. Each step is a separate action. For teams that meet repeatedly on predictable schedules, Doodle polls are unnecessary overhead. For one-off large group scheduling, they're still useful.
SavvyCal is a polished Calendly alternative with better timezone UX — it shows the guest's own timezone automatically and lets them overlay their calendar on yours. The quality is high and the design is thoughtful. It's still fundamentally a booking link product: it shows one person's availability, not a multi-party heatmap. If you're an individual selling consulting time or scheduling 1:1s, SavvyCal is worth evaluating. If the problem is coordinating three engineers across three continents, it's the wrong tool.
Cal.com is the open source scheduling platform — think Calendly but with full source access and a self-hosting option. It has a large ecosystem, good integrations, and an API that lets you build scheduling into your own product. The trade-off is complexity: self-hosting requires maintenance, and the hosted version isn't cheaper than competitors. Like SavvyCal, it's optimised for booking-link scheduling, not for the specific problem of coordinating a group across timezones from scratch.
The three platforms that handle the overwhelming majority of calendar invites in the world — and none of them can show you when a group of people across different timezones is actually free, before you propose a time.
| Feature | thyme.works | Google Calendar | Microsoft Outlook | Apple Calendar |
|---|---|---|---|---|
| Visual timezone overlap across attendees | ✓ | — | — | — |
| See all attendees' free/busy before proposing | ✓ | Partial | Partial | — |
| Automatic DST conversion per attendee city | ✓ | — | — | — |
| Suggest best slots across timezones | ✓ | — | — | — |
| Send invite with per-attendee local time | ✓ | — | — | — |
| Works without attendees having the same platform | ✓ | — | — | — |
Google Calendar does one thing well in this space: if everyone is on Google Workspace, the 'Meet with' view shows a merged free/busy grid. But that grid has no timezone context — it shows blocks of busy time without telling you what city each person is in or whether 3pm is 3pm for everyone. Proposing a time still means mentally converting zones yourself, then hoping everyone interprets the invite correctly. There's no heatmap, no overlap window, no AI suggestion. For a product used by hundreds of millions of people to coordinate across time zones every day, the gap is remarkable.
Outlook's Scheduling Assistant shows attendee availability on a timeline — the best native implementation of any calendar platform. The problem is the same one Google has: the timeline is in a single timezone (yours), so an attendee in Singapore who is busy at 9am local time shows as busy at an unlabelled UTC offset. You're left doing the conversion in your head or in a separate tab. Outlook also has a 'Suggested times' feature, but it suggests based on raw availability, not timezone-aware working hours. It will suggest 11pm Singapore time if everyone else is free.
Apple Calendar is the cleanest of the three to look at and the weakest at group scheduling. There is no scheduling assistant, no free/busy grid for attendees, and no timezone overlap view. Creating a meeting across timezones in Apple Calendar means knowing the times yourself, entering the event in one timezone, and trusting that attendees' devices will convert correctly. It does. But finding the right time in the first place — that's entirely on you. Apple Calendar is a display tool, not a scheduling tool.
Calendly, Cal.com, and SavvyCal solve a different problem: sharing your own schedule so others can book into it. That works well for 1:1s with external people — clients, candidates, leads.
thyme.works solves the harder problem: three or four people, different cities, different calendars, trying to find a slot that works for everyone. The heatmap makes the overlap visible instantly. Real calendar scanning replaces the guesswork. The invite goes out automatically.
World Time Buddy tells you what time it is somewhere. Doodle runs a poll. thyme.works finds the slot and books it.
Try it free →