About This Site

📅

Casey Marlin

I build small, honest utilities for calendar files. This site started the usual way: a spreadsheet of events, a calendar that wouldn't take it, and a page of online converters that all wanted my file uploaded to somebody's server first. Calendar data is personal — meeting names, addresses, appointments — so I built the converter I wanted: one that does the whole job in the browser tab and can prove it.

Principles

Client-side or it doesn't ship. Every tool here — CSV to ICS, ICS to CSV and the ICS viewer — parses and generates files entirely in your browser. You can watch the network tab: converting a file makes zero requests.
Standards, actually followed. Generated files implement RFC 5545 properly: CRLF endings, 75-octet line folding, text escaping, unique UIDs and real VTIMEZONE definitions computed from the timezone database in your browser.
Tested against reality. The conversion engine ships with an automated test suite (93 assertions covering parsing, generation and full round trips), and output is validated by importing into Google Calendar, Outlook and Apple Calendar.
Honest docs. The import guides describe what each calendar app actually does in 2026 — including the annoying parts, like Apple Calendar having no CSV import and new Outlook dropping it.

Contact

Found a file the converter mishandles or a guide that's gone stale? Reach out at hello@csvtoics.app— broken-file reports (with the file, if it's shareable) are the most useful thing you can send.