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ICS Calendar File Viewer, Validator & CSV Export

Open, inspect, validate, and convert .ics calendar files to CSV and JSON.

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About ICS Calendar File Viewer, Validator & CSV Export

Free browser-based iCalendar (.ics) viewer and validator. Inspect calendar events, check RFC 5545 compliance, parse attendees, recurrences, and timezones, and export to CSV or JSON with zero server uploads.

What is an ICS file and how do I open it online?

An ICS file (Internet Calendaring and Scheduling, iCalendar standard RFC 5545) is a universal calendar format used by Google Calendar, Apple Calendar, Microsoft Outlook, and Yahoo Calendar to share events, invitations, and appointments. Our free ICS viewer parses the file directly inside your browser so you can view event titles, dates, timezones, locations, attendees, and recurrences without importing them into your personal calendar.

How does the RFC 5545 ICS validator work?

The validator checks your iCalendar file against the official IETF RFC 5545 specification. It verifies mandatory properties (BEGIN/END tags, VERSION:2.0, PRODID, VEVENT UIDs, and DTSTAMP timestamps), checks date-time formatting (UTC vs local timezones), ensures DTEND is chronologically after DTSTART, and detects malformed recurrence rules (RRULE).

Can I export .ics files to CSV for Microsoft Excel and Google Sheets?

Yes! Click "Export to CSV" to generate a clean, spreadsheet-ready CSV file formatted with standard columns (Subject, Start Date, Start Time, End Date, End Time, All Day, Description, Location, Organizer, Status). You can open it in Excel, Numbers, or Google Sheets with one click.

Is my calendar data secure and private?

Yes, 100%. The parser runs entirely client-side using JavaScript in your browser. Your calendar files, meeting notes, attendee email addresses, and private schedules are never transmitted to any external server.

📐 Methodology & Reference Accuracy: Calculations, formulas, and conversions execute locally in your web browser. Output models are benchmarked against official reference standards and updated for 2026.

🔒 This tool runs entirely in your browser. Nothing is uploaded or stored.

Ics Viewer Validator – free online converters
ICS Calendar File Viewer, Validator & CSV Export – free online converters

Background reading: Ics Viewer Validator on Wikipedia. More: all converters.

Frequently Asked Questions about ICS Calendar File Viewer, Validator & CSV Export

How do I open an .ics file on a computer without Outlook or Apple Calendar?

Simply drag and drop your .ics file into this tool or paste its contents. It immediately displays all meetings, start/end times, agendas, and locations directly in your web browser.

What causes common ICS validation errors?

Common errors include missing VERSION:2.0, missing mandatory UID or DTSTAMP fields on VEVENT components, improper line folding (lines exceeding 75 octets without CRLF + space), and invalid ISO 8601 date-time formats.

How do I convert an ICS calendar invite to Excel CSV?

Drop your .ics file into the viewer and click "Download CSV". The tool converts all events into standard comma-separated format compatible with Excel and Google Sheets.

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