Calendar Author — .chroncal

Define a custom calendar system and export a portable .chroncal file. Name your months, set intercalary days, configure leap rules, and anchor your epoch — no code required.

schemas.openchronology.org/v0.3/calendar
↑ Import .chroncal prefill form
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Drop a .chroncal file to edit it
or click to browse · .chroncal or .json
01 Calendar Identity required
Human-readable name of this calendar.
Stable key used in .chron references. Lowercase, hyphens only.
Where this file will live permanently. Enables cross-site referencing.
02 Calendar Structure required
Load preset →
Month-based calendar with named periods and optional leap rules. Suitable for most real and fictional calendars.
Year length 365 days (auto-sum)
days
Leap Rule Settings
The year from which the leap cycle begins counting. Defaults to 0 (calendar epoch).
Name of a single unit in this calendar (e.g. "stardate", "day", "Ma").
One standard Earth day = 86400 s. Required for cross-calendar comparison.
03 Epoch Anchor optional
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Anchors this calendar's epoch to a real-world reference. Required for cross-universe temporal comparison in the viewers.

Universe ID the reference value is expressed in. Use "real" for Earth.
ISO 8601 datetime in the reference universe corresponding to this calendar's year zero.
04 Value Format required
Controls how temporal.*_value strings in .chron files are parsed by this calendar.
.chroncal untitled-calendar.chroncal