Calendar and contacts converter

A contacts export is everybody you know, with their phone numbers and email addresses. A calendar export is where you have been and where you will be, with the names of the people you were with. Neither is something to hand to a website in exchange for a file conversion.

Both run entirely in your browser here. Nothing is transmitted, nothing is stored, and you can verify it by disconnecting from the network and converting anyway.

Calendar entries have structure a flat table does not: recurrence rules, attendees with their own responses, alarms, time zones. Flattening to CSV keeps what fits in columns and necessarily simplifies the rest, which is fine for reviewing or bulk-editing and not a lossless round trip.

The same applies to contacts, where one person can have several numbers, addresses and emails. The pages say how those become columns rather than leaving you to discover it.

Google Calendar exports from Settings, Import and export, which produces one ICS per calendar or a ZIP of all of them. Apple Calendar exports per calendar from the File menu. Outlook exports a single calendar to ICS from Open and Export. Contacts follow the same pattern: Google Contacts offers vCard as an export format, Apple Contacts exports selected cards, and Outlook exports CSV directly.

The difference worth knowing is that some of these hand you one file containing everything and others hand you a folder of separate cards. A folder of individual VCF files is normal from Apple and confusing if you expected one file — each card is a complete vCard and they can be concatenated into a single file with nothing more than a text editor.

An ICS event stores its time either as a local time with a named zone, or as UTC with a Z suffix, or as a floating time with no zone at all. Those are three different things and they behave differently when the file is read somewhere else.

Flattened into a spreadsheet the distinction usually disappears, and an appointment at 09:00 in Berlin becomes the string 09:00 with nothing saying which nine. If the export is going to be re-imported anywhere, keep the original ICS alongside the CSV — the spreadsheet is for reading and editing, not for round-tripping.

vCard 2.1, 3.0 and 4.0 are all in circulation and all use the `.vcf` extension. They encode names, photographs and non-ASCII characters differently, which is why a contacts file exported from one phone sometimes arrives at another with mangled accents or a missing photograph.

Version 3.0 is the most widely accepted and is what most systems export. If a contacts import fails or produces garbled names, the version mismatch is the usual explanation rather than a corrupt file, and converting through CSV is a reliable way to strip the problem out.

The common reason to make one is bulk editing: finding duplicates, fixing a company name across two hundred cards, removing everyone from a former job. A spreadsheet does that in minutes where a contacts application does it one card at a time.

Converting back is where care is needed. Column headings have to match what the target application expects, and each one names them differently — Google, Outlook and Apple all use different labels for the same field. Exporting a small test file from the destination first and matching its headings is far quicker than repairing a failed import of two thousand contacts.

A weekly meeting is one entry in a calendar file with a repeat rule attached, not fifty-two entries. A spreadsheet has nowhere to put that rule, so what lands in the CSV is the series as a single row with its start date, and the individual occurrences are simply not there.

This is worth knowing before counting anything. A year of meetings looks like one line, and a CSV exported for a timesheet or an audit will undercount every repeating commitment in the calendar. Where the occurrences matter, they have to be expanded in the calendar application before the export, not after.

A meeting entry carries the addresses of everyone invited, their response status and often the organiser's account name. Exporting a work calendar therefore exports a partial list of colleagues, clients and their email addresses along with it.

That makes a calendar export a document about other people as well as about you, which is the part that is easy to forget when the file feels like a personal one. It is also why the conversion on this page happens on your own machine: handing that particular file to a server would be handing over somebody else's contact details, not only your own schedule.