Convert XLSX to ICS

Drop an .xlsx file and get back a standard .ics calendar file. Koyomi parses the workbook in your browser, detects the title, date, time and location columns from the headers, and writes an iCalendar file any calendar app can import.

The .xlsx format is what most software produces when you click "Export to Excel" — property-management tools, booking systems, Airtable, Notion. A landlord with lease starts, lease ends, inspections and renewal deadlines in one export can turn it into a calendar in a minute, one row per event, with the property address in the location field.

Dates that mix real date cells with typed text ("1 September 2026" next to 2026-09-15) are handled, and day-first versus month-first is inferred from the data with a manual override if the guess is wrong. Times default to your browser's timezone, or pick another.

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

What's the difference between .xlsx and .xls?
.xlsx is the current Excel format (2007 onward); .xls is the older binary one. Koyomi reads both, plus CSV, so it doesn't matter which one your software exported.
How should I lay out lease start and end dates?
One row per date you want to see. "Lease starts — 12 Oak St" on one row and "Lease ends — 12 Oak St" on another gives you an event on each day that matters, rather than one long block on the calendar.
Can I put the property address in the event?
Yes. A column headed Location is picked up automatically and becomes the event location, which calendar apps show with a map link. If yours is called Address or Property, map it to Location with the dropdown.
The dates parsed month-first but they're day-first. Can I fix it?
Yes. Koyomi infers the order from the data, but when a file is ambiguous (every day number is 12 or under) there's a manual day-first / month-first toggle, and the preview updates immediately.
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.