Guides

Inventing calendars: Threadbound's Multi-calendar module

By the Threadbound team · October 2026

Start with your main calendar

You don't need a module for a single custom calendar. In Settings, Calendar, you can set the months and their lengths for the project you're in. This is the calendar that positions everything on the Timeline and Board. Changing it re-reads your existing events' dates against the new months. It doesn't rewrite them.

When you need more than one

Plenty of stories have several peoples who count time differently: elves and dwarves, an empire and the old kingdom it replaced. Install Multi-calendar from Settings, Modules (it is per project) and a Calendars tab appears. Add a calendar there with a name and a list of months, each with its number of days.

Aligning calendars

A new calendar's Year 0 starts on the same day as your main calendar's by default, which is rarely what you want. Aligning tells Threadbound how they relate. There are two ways, using the align button beside a calendar:

• By date: give a date in each calendar that is the same day.
• By event: pick an existing event, which already has a date in your main calendar, and say what date it falls on in this calendar.

The by-event route suits stories where a famous day anchors every calendar, like a founding or a battle.

Converting dates

The converter on the Calendars tab turns a date in any calendar into a date in any other, including your main one. Enter the date under "From", choose the calendar to convert "To", and the result appears below.

Secondary dates on the Timeline

With at least one calendar set up, the Timeline toolbar gets a "Secondary dates" checkbox. Switch it on and the ruler shows a smaller second line under each date. It can show two calendars at once, and a small control at the left of the ruler lets you choose which two, labelled by initials ("Elven Reckoning" becomes "ER"). Hover for the full name.

Entering dates in another calendar

When you add or edit an event, a Calendar dropdown appears next to the date fields. Switch it and the same date is shown in that calendar's terms, so you can type a date the way your characters would write it. Threadbound converts it back and stores it against your main calendar, so nothing changes about how the event is positioned.

Editing and deleting

Each calendar on the tab has buttons to align, edit and delete. Deleting asks for confirmation and only removes the calendar and its alignment. Your events keep their dates, because those are stored in the main calendar.

Backups

Calendars are included in Threadbound's normal backup, even while the module is switched off.