Turn a spreadsheet into calendar events

Any spreadsheet with one event per row can become a calendar: CSV with any delimiter, .xlsx, .xls, or a Google Sheet you've downloaded. Koyomi detects the title, date, time and location columns, shows you the parsed events, and writes an .ics that every calendar app imports.

The spreadsheet doesn't have to be tidy. A volunteer rota for a community group usually mixes date styles from whoever edited it last, has a Notes column, and puts the venue under a heading like Where. Koyomi reads ISO, US, European and written-out dates side by side, and any column it doesn't recognize is mapped with a dropdown before you download.

Starting from scratch? Grab a spreadsheet template with the right headers, fill it in, and it converts without any mapping. Rows with a date but no time become all-day events; rows missing a title or date are skipped and flagged in the preview, so nothing vanishes silently.

After you download the .ics

Google Calendar

  1. Open calendar.google.com on a computer (the mobile apps can't import files).
  2. Click the gear → Settings → Import & export.
  3. Select the .ics file, choose which calendar to add the events to, and click Import.

Outlook

  1. Outlook on the web / new Outlook: Calendar → Add calendar → Upload from file → pick the .ics and a destination calendar.
  2. Classic Outlook for Windows: File → Open & Export → Import/Export → Import an iCalendar (.ics) file.
  3. Choose Import (merge into your calendar) rather than Open as New, unless you want a separate calendar.

Apple Calendar

  1. Mac: double-click the .ics, or File → Import in Calendar, then pick the calendar to add to.
  2. iPhone / iPad: open the .ics from Files or Mail and tap Add All.
  3. Events added to an iCloud calendar sync to every device.

Frequently asked questions

Which spreadsheet formats can I use?
CSV with comma, semicolon or tab delimiters, .xlsx and .xls. Google Sheets, Numbers, LibreOffice and most booking or HR tools can export to one of those. Nothing is actually uploaded — the file is read in your browser.
What should the columns be called?
Title (or Subject, Event), Start Date, Start Time, End Date, End Time, All Day Event, Location, Description and URL are recognized automatically. Other names are fine — you get a dropdown per column to say what it holds.
Some rows are section headings or blank lines. Will they break the import?
No. Rows without a usable title or date are skipped, and each one is listed with a reason in the preview, so you can fix the spreadsheet if it was meant to be a real event.
Which calendar apps does the file work with?
All of them. The output is a standard .ics file: Google Calendar, Outlook, Apple Calendar, Thunderbird, Proton, Fastmail and any app that can import iCalendar.
Is my spreadsheet uploaded anywhere?
No. Parsing and the .ics file are produced entirely in your browser — the file never leaves your device. That's also why there is no size limit, no queue and no account.
Is this really free?
Yes. Every input format, every option, no sign-up, and nothing added to the calendar file.
Does it support recurring events?
Not yet. Each row becomes one single event. For a weekly class or shift, put one row per occurrence — filling a date column down in a spreadsheet takes seconds.