twineconvert

free · in-browser · no upload

CSV to ICS
Converter

Drop your CSV file. We'll convert it to ICS right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .csv

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a CSV from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your ICS the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Why convert CSV → ICS

What this conversion is actually for

Bulk-creating calendar events by hand is painful. If your events are in a spreadsheet (a class schedule, a content calendar, a shift roster), converting to .ics lets you import them all into Google Calendar, Apple Calendar, or Outlook in one go.

A real example

You have a 40-row content calendar in Sheets. Add summary, start, and end columns, export CSV, convert to .ics here, import into Google Calendar. Forty events created in one step.

Troubleshooting

"CSV needs a summary or start column".

The converter needs at least a 'summary' or 'start' header to build events. Match the headers: summary, start, end, location, description, allDay. Dates as YYYY-MM-DD HH:MM:SS or YYYY-MM-DD.

All-day events show a time.

Set the allDay column to true and use a date-only start (YYYY-MM-DD). The converter then writes a DATE-valued event the calendar treats as all-day.

Formats involved

About CSV and ICS

CSV, Comma-Separated Values

CSV is plain text, one row per line, fields separated by commas. The simplest possible tabular data format, which is exactly why it remains the most portable: every spreadsheet, database, programming language, and analytics tool reads CSV. Tradeoffs: no formulas, no formatting, no multiple sheets, and various edge cases around quoting fields that contain commas or newlines.

How to open

Excel, Google Sheets, Apple Numbers, LibreOffice Calc, any text editor, every database import wizard, every programming language with one line of code.

Full CSV format guide →
ICS, ICS

ICS is a file format we support converting. Detailed format information is being added, for now, drop your file in the converter above and you'll get the conversion you came for.

How to open

Most operating systems open this format with a default application; if not, search for a free reader/viewer for the format.

Full ICS format guide →

Convert your CSV to other formats

FAQ

Common questions

Is this CSV → ICS converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert CSV to ICS?

Universal tabular data interchange. File interchange. The most common reason to convert is compatibility, ICS works in places where CSV doesn't, or vice versa.

How do I open a CSV file in the first place?

Excel, Google Sheets, Apple Numbers, LibreOffice Calc, any text editor, every database import wizard, every programming language with one line of code.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.