calendr.events

Conversion · 8 minute guide

How to Convert CSV to an ICS Calendar File

A CSV file is a table; an ICS file is a calendar. Conversion is therefore more than changing the extension. Each spreadsheet row must be mapped to an event, and ambiguous dates, timezones, all-day rules and multiline text must be resolved before the result is safe to import.

Published and reviewed by Whitle · September 26, 2026

Quick answer

What matters most.

  • A title and start date are the practical minimum; explicit end dates, times and timezone make the result more reliable.
  • Use ISO-style dates such as 2026-10-02 whenever possible to avoid month/day ambiguity.
  • Preview every mapped row and fix rejected rows before downloading the ICS file.

01

Recommended CSV columns

Your headers do not have to use these exact names when the converter provides explicit column mapping. Mapping is safer than guessing because exports from Excel, Google Sheets, Outlook and internal systems use different labels.

ColumnExamplePurpose
TitleTeam planningThe event name
Start Date2026-10-02Required starting calendar date
Start Time09:30Optional for all-day events
End Date2026-10-02Useful for overnight or multi-day events
End Time10:15The event's finishing time
All DayfalseMakes date-only intent explicit
TimezoneAmerica/TorontoNamed timezone for timed events
LocationStudio 2Optional place
DescriptionBring the draftOptional notes

02

Prepare the spreadsheet

  1. 1Put one event on each row and keep one header row at the top.
  2. 2Replace ambiguous numeric dates such as 03/04/2026 with ISO dates or choose the intended date convention explicitly.
  3. 3Separate date and time columns when possible. Use consistent 24-hour times or unambiguous AM/PM values.
  4. 4Mark all-day events explicitly instead of giving them midnight times.
  5. 5Export as UTF-8 CSV so accented characters and non-Latin text survive.
Important:Do not rename an .xlsx workbook to .csv. Export or save it as CSV, or use the Excel-to-ICS tool for the workbook directly.

03

A clean example

The second row has no time and should be confirmed as an all-day event during mapping. For an all-day ICS event, the end date is exclusive: a one-day event on October 12 ends on October 13 in the file. A good converter handles that detail without displaying the event as two days.

Title,Start Date,Start Time,End Date,End Time,Timezone,Location
Team planning,2026-10-02,09:30,2026-10-02,10:15,America/Toronto,Studio 2
Company holiday,2026-10-12,,,,,

04

Choose dates and timezones deliberately

  • ISO dates: 2026-10-02 is unambiguous and sorts naturally.
  • Numeric dates: 10/02/2026 can mean October 2 or February 10, depending on convention.
  • Named timezone: America/Toronto preserves the intended local clock time across seasonal offset changes.
  • UTC: appropriate when the source times are explicitly universal, not merely because the spreadsheet lacks a timezone column.
  • Floating time: useful for a clock time intended to remain 09:00 wherever it is used, but calendar apps may interpret it differently.

05

Convert and review

  1. 1Open the CSV-to-ICS converter and choose the CSV file or paste its text.
  2. 2Map title, start, end, all-day, timezone, location and description columns.
  3. 3Choose the date convention and default timezone only where the rows need them.
  4. 4Review accepted and rejected rows. Fix errors instead of silently excluding important events.
  5. 5Download the ICS file, open it in a viewer and test-import it into a temporary calendar.

06

What CSV cannot preserve

CSV is a flat table and has no universal calendar schema. It does not naturally represent nested reminders, attendee parameters, timezone definitions, recurring exceptions or arbitrary app-specific properties. Converting an existing ICS file to CSV and back may therefore be lossy even when the visible title and dates look correct.

If your source is already an ICS calendar and you only need to change a few events, use a calendar editor instead of taking a round trip through CSV.

Common questions

A few direct answers.

What columns are required for CSV to ICS?

A usable event needs at least a title and start date. Timed events also need a start time and an explicit timezone decision. End values, location and description are optional but useful.

Can I convert an Excel file to ICS?

Yes. Use an XLSX-to-ICS converter for the workbook directly, or export the worksheet as UTF-8 CSV and map its columns.

Why are my imported dates reversed?

The converter or calendar probably interpreted numeric dates using a different month/day convention. Prefer YYYY-MM-DD or explicitly select the source convention before conversion.

Primary sources.

Provider interfaces and limits can change. We review official documentation when this guide is materially updated.

Tools for this job.

CSV → ICS

Map spreadsheet columns to events and preview before exporting.

Excel → ICS

Convert a local XLSX worksheet using explicit column mapping.

TSV → ICS

Turn tab-separated spreadsheet rows into calendar events.

ICS Validator

Check the whole file without making any changes.

Keep learning

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