Free online calendar and time tools
Date calculators, timezone converters, ICS file generators, and calendar utilities.
Six tools for scheduling and running things, built on the time zone database your browser already ships. Timezone Converter reads the complete IANA zone list through Intl.supportedValuesOf, so every zone your device knows is searchable rather than a curated shortlist, with quick entries for New York, London, Paris, Dubai, Mumbai, Singapore, Tokyo, Sydney and twenty-odd others. Pick a source time and it renders the same instant in every zone you have added, marks which of them are currently on summer time, and offers a slider that sweeps the hour across all of them at once against a working-day window you set, so an overlap becomes visible rather than calculated. Favourites and the 12- or 24-hour preference persist in your browser's local storage, not in an account. Meeting Time Planner is the multi-participant version of that idea: add people with their own zones and working hours, and it scores every hour of the day by how many of them are inside their own window, then lists the best slots with each person's local time ready to paste into an invitation. ICS Calendar Generator writes a real RFC 5545 file rather than a link: a VEVENT carrying SUMMARY, DESCRIPTION and LOCATION, an optional RRULE for daily, weekly, monthly or yearly repetition, a VALARM reminder block, ATTENDEE lines as mailto entries, an X-WR-TIMEZONE hint, and correct all-day handling with DTSTART as a date value. The downloaded .ics imports into Google Calendar, Outlook, Apple Calendar and anything else that reads the standard, and presets for a team meeting, lunch, birthday, workshop, sprint review or full conference day give you a working starting point. Countdown to Date runs several live counters at once, breaking each interval into years, months, days, hours, minutes and seconds and continuing past zero to count upward from a date that has already passed. Event Timeline turns a day into an ordered run sheet: entries with a start and end time, a category from ceremony and reception through talks, breaks, workshops and transport, an icon, drag-to-reorder, and an export as PNG or straight to the printer, with starting timelines for a wedding day, a conference, a product launch and a birthday party. Seating Chart lays out round and rectangular tables you drag into position, assigns named guests to individual seats with colour-coded groups, takes a bulk paste of a guest list, and exports the plan as a PNG or the assignments as CSV.
5 tools · always free · no account needed
Timezone Converter
Convert time across multiple cities and zones
ICS Calendar Generator
Create downloadable .ics calendar events
Meeting Time Planner
Find overlapping hours across 3+ time zones
Countdown to Date
Countdown to a specific future date with live timer
Seating Chart
Drag-and-drop table layout for weddings and events
How to choose the right tool
Two of these answer when, and four produce something you hand to other people. If you only need to know what time it is elsewhere, or what 14:00 in Copenhagen is in Chicago, Timezone Converter is the direct answer and its overlap slider covers the simple two- or three-person case. Move to Meeting Time Planner once there are enough participants that the answer is a compromise rather than a lookup, because it ranks hours by how many people are inside their own working day. Once a slot is agreed, ICS Calendar Generator turns it into a file everyone can import, which is far more reliable than a time written in the body of an email and is the only option here carrying a reminder and a recurrence rule. Countdown to Date is for a deadline rather than a meeting: a launch, a renewal, a trip, an expiry. The last two belong to the day itself — Event Timeline for the run sheet you print and give to a venue or a compere, Seating Chart for who sits where. Note that the .ics generator writes an event, it does not send an invitation.
Frequently asked questions
Do these tools handle daylight saving time correctly?
Yes, because they do not implement time zones themselves. Every conversion goes through the browser's Intl.DateTimeFormat with a named IANA zone such as Europe/Copenhagen, so the offset used is the one in effect on the date in question, including the transition weekends where Europe and North America change on different dates and the southern hemisphere moves the other way. The converter also marks which zones are currently observing summer time. The accuracy therefore tracks your device's own time zone database, which is updated with the operating system.
Which time zones can I choose from?
All of them your browser knows. The list comes from Intl.supportedValuesOf with the timeZone key, which returns the full IANA set — several hundred entries, including the ones people actually need and the historically awkward ones such as Asia/Kolkata at UTC+5:30, Australia/Adelaide at +9:30 and Pacific/Chatham at +12:45. Quick-pick buttons cover the major financial and tech centres, and the search box filters the whole list. If a brand-new zone has been added to the database and your device has not updated, it will be missing here too.
Will the .ics file work in Google Calendar and Outlook?
It should, because the output follows RFC 5545 rather than any one vendor's dialect: a VCALENDAR wrapper at VERSION 2.0, a VEVENT with SUMMARY, DESCRIPTION, LOCATION and the timestamps, RRULE for recurrence, VALARM for the reminder and ATTENDEE lines as mailto addresses. Google Calendar, Outlook, Apple Calendar, Thunderbird and most others read that format. Behaviour differs slightly at the fringes — how a client displays an all-day event spanning a time zone boundary, or whether it honours an alarm on an imported event — so open the file once yourself before sending it to twenty people.
Does the ICS generator send invitations to attendees?
No. It writes ATTENDEE lines into the file so the addresses travel with the event and appear in the importing calendar, but nothing is transmitted — there is no mail server and no calendar connection behind this page. Sending is your step: attach the downloaded .ics to an email, or import it into your own calendar and use that calendar's invite function, which is the route that gets you RSVP tracking. Think of the generator as producing a correctly formatted event file, not as running a scheduling service.
What is kept between visits, and what disappears on reload?
Two tools remember, four do not. Timezone Converter writes your favourite zones and your 12- or 24-hour preference to this browser's local storage, and Seating Chart saves the tables and guest assignments the same way, so both survive a reload and a restart on this device. Neither syncs anywhere, and both are lost if you clear site data or work in a private window. Meeting Time Planner, ICS Calendar Generator, Countdown to Date and Event Timeline keep nothing: their contents live in the page only. Export the PNG, CSV or .ics before you close the tab.
How does the meeting planner decide which slot is best?
It converts each hour of the day into every participant's local time and counts how many of them fall inside the working window you configured for that specific person, then ranks hours by that count and reports the percentage available. What it optimises is the number of people inside their own normal day, not fairness over repeated meetings, seniority or travel. For a group spread across Europe, North America and Asia there is frequently no hour that suits everyone, and the ranking makes that visible early — at which point the honest options are rotating the awkward slot or recording the session.
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