ICS Calendar Event Generator
指导
ICS Calendar Event Generator
Build a standards-compliant .ics calendar file in seconds, then download it or copy the raw iCalendar text. Fill in the event details, choose a timezone and an optional repeat rule, add a reminder, and you get a clean RFC 5545 file that imports cleanly into Apple Calendar, Google Calendar, Outlook, Fastmail, Thunderbird, Nextcloud, and any other client that speaks iCalendar.
如何使用
- Enter the event title, optional description, and a location or meeting URL.
- 选择 Timed 或 All-day. For timed events, fill in the start and end times.
- Choose a timezone. Use Floating for “whatever zone the calendar opens in”, 世界标准时间 for absolute times, or pick a specific IANA zone such as
America/Los_Angeles. - Optionally set a repeat rule (daily, weekly, monthly, yearly), an interval, and an occurrence count.
- Optionally add a reminder offset, organizer, and a list of attendee emails.
- Click the download icon to save the
.icsfile, or copy the raw iCalendar text and paste it into an email or chat.
特征
- Standards-compliant output – Generates valid
VCALENDAR/VEVENTblocks per RFC 5545, includingPRODID,UID,DTSTAMP, and proper 75-octet line folding. - All-day or timed events – Switches between
DTSTART;VALUE=DATEand full date-time forms automatically. - Smart timezone handling – Choose floating times, UTC with
Zsuffix, or a named IANA zone written as aTZIDparameter. - Recurring events – Emits
RRULEfor daily, weekly, monthly, or yearly repetition with optionalINTERVAL且COUNT. - Reminders – Adds a
VALARMblock with a configurable trigger from 0 minutes up to 1 week before the event. - Organizer and attendees – Emits
ORGANIZER且ATTENDEEproperties withCNdisplay names andmailto:addresses. - Safe text escaping – Commas, semicolons, backslashes, and newlines are escaped exactly as the spec requires, so descriptions never corrupt the file.
- 纯客户端运行 – Everything runs in your browser, so the event details never leave your computer.
何时使用此工具
- Sending a meeting invite from an app or newsletter that has no calendar integration.
- Generating an “Add to calendar” file on an event landing page.
- Recreating a corrupted recurring event without wrestling with a heavyweight client UI.
- Testing how a downstream calendar parses unusual recurrence or alarm combinations.
- Producing bulk event files where the input data lives in a spreadsheet or doc.
常问问题
-
What is an ICS file?
An ICS file is a plain-text calendar payload that follows the iCalendar standard defined by RFC 5545. It begins with a VCALENDAR envelope and contains one or more VEVENT components describing meetings, all-day events, reminders, recurrence rules, and attendees. Almost every modern calendar app understands ICS, which is why it is the de facto interchange format for events between vendors.
-
What is the difference between floating, UTC, and a named timezone?
A floating time has no timezone at all, so the calendar shows the same wall-clock value no matter where you are. A UTC time is anchored to Coordinated Universal Time and shifts on the display side based on the viewer's offset. A named IANA timezone like Europe/Paris emits a TZID parameter, telling the calendar to interpret the time as a local moment in that specific zone, which is the only approach that survives daylight saving transitions correctly.
-
How does RRULE describe a recurring event?
RRULE is an iCalendar property that defines a repeating pattern using a FREQ value (DAILY, WEEKLY, MONTHLY, or YEARLY) together with optional modifiers such as INTERVAL, COUNT, UNTIL, BYDAY, BYMONTHDAY, and BYMONTH. The first instance is anchored by DTSTART and every later instance is derived by applying the rule, which keeps the file compact and lets calendar clients expand or collapse the series on demand.
-
Why is DTEND for an all-day event exclusive?
RFC 5545 specifies that when an event uses VALUE=DATE, DTEND points to the first day after the event ends rather than the last day of the event itself. A one-day event on May 1 therefore has DTSTART;VALUE=DATE:20260501 and DTEND;VALUE=DATE:20260502. This convention mirrors how half-open intervals work in computer science and prevents off-by-one errors when calendars compute duration.
-
What does the UID property guarantee?
UID is a globally unique string identifying a specific event across calendar systems. Two ICS files sharing the same UID are treated as the same event, which is how updates and cancellations propagate: the client receives a new VEVENT with the original UID and a higher SEQUENCE number, then replaces the existing entry. A good UID combines a timestamp with strong randomness and a domain suffix to avoid collisions.
-
How does line folding in iCalendar work?
iCalendar requires content lines to be limited to 75 octets, and longer values are folded by inserting a CRLF followed by a single whitespace character. A parser reverses the operation by stripping any whitespace that immediately follows a CRLF. This rule is essential for compatibility with very old mail transports and is one of the most common sources of malformed ICS files in the wild.
