Convert Excel to ICS

Koyomi opens .xlsx and .xls workbooks directly — no saving as CSV first — and turns the rows into a standard .ics calendar file that Google Calendar, Outlook, Apple Calendar and every other calendar app can import.

Shift rosters are the classic case: an ops or HR spreadsheet with one row per shift, a date column, a start and end time, and a name. Excel stores those dates as real date cells or, after a copy-paste, as serial numbers like 46266. Koyomi reads both correctly, so you don't get every shift landing in January 1900. Workbooks with several sheets show a sheet picker.

Before you download there's a preview of every event, so you can check the roster parsed the way you expect. Everything runs locally in the browser — the workbook is never uploaded, and there is no row limit.

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

Do I have to save my Excel file as CSV first?
No. Drop the .xlsx or .xls straight in. Skipping the CSV step also avoids Excel rewriting your dates into the regional format on export.
My workbook has several sheets. Which one is used?
You pick. When a workbook has more than one sheet, Koyomi shows a sheet picker before parsing, and only the selected sheet becomes events.
Excel shows my dates as numbers like 46266. Is that a problem?
No. Those are Excel date serials, and Koyomi converts them to real dates. Formatted date cells, typed text dates and times written as 9:00 or 9am are all read too.
Can one ICS file hold a whole month of shifts?
Yes. One row becomes one event, and the file holds as many events as the sheet has rows. Calendar apps import the whole file into one calendar in a single step.
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.