Import a CSV into Outlook Calendar
Outlook's CSV import is the "Import from another program or file" wizard: pick the file, then map each column to an Outlook field by hand, with no preview and no warning when a date is misread. Koyomi converts the CSV to an .ics instead, which Outlook imports straight into a calendar in one step — desktop, web and the new Outlook alike.
An office manager with a quarter of training sessions in a CSV — session, date, start, end, room, trainer — maps any unrecognized column with a dropdown, sets the timezone the times were written in, and downloads. Because times are stored as exact instants, a 09:00 session written in Berlin time shows as 08:00 for the London team when they import the same file.
Row-level warnings show anything that couldn't be parsed before you download. Outlook on the web and the new Outlook accept only .ics through Add calendar → Upload from file, and that's what Koyomi produces.
After you download the .ics
Outlook
- Outlook on the web / new Outlook: Calendar → Add calendar → Upload from file → pick the .ics and a destination calendar.
- Classic Outlook for Windows: File → Open & Export → Import/Export → Import an iCalendar (.ics) file.
- Choose Import (merge into your calendar) rather than Open as New, unless you want a separate calendar.
Frequently asked questions
- Why does Outlook's own CSV import go wrong?
- It maps columns to fields by hand, reads dates according to your Windows regional settings, and has no way to express a timezone per file. An .ics carries all of that inside it, so Outlook has nothing to guess.
- Import or Open as New — which do I pick in Outlook desktop?
- Import adds the events to your existing calendar. Open as New creates a separate calendar shown side by side. For a schedule you want alongside your own meetings, choose Import; for something to toggle on and off, Open as New.
- Does this work with the new Outlook and Outlook on the web?
- Yes. Both use Add calendar → Upload from file, which takes an .ics and asks which calendar to put it in. That's the only import path they offer — CSV isn't an option there.
- Will Outlook duplicate events if I import the file again?
- In most cases, no. Every event has a stable ID, so re-importing the same spreadsheet updates matching events rather than adding copies. Check after your first re-import, since behaviour varies between Outlook versions.
- 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.