Fantasy Calendar Builder

Months, weeks, leap days and moons — named in your own language.

Date tools

Day of year → date

Add days

Year structure
Months and intercalary days
#NameMeaningDaysIntercalaryGroupLock
Unit names

Optional, e.g. Sun / Span / Moon / Winter. Used in labels and dates; blank = default. Plural adds “s” (write “Wolf/Wolves” for a custom plural).

Month groups
Grouping levels above months, innermost first
LevelNameContains

Optional nesting above months (e.g. 3 Months = 1 Season, 4 Seasons = 1 Age). Intercalary entries sit outside the groups.

Leap rule

0 = no leap years. Gregorian is every 4, except every 100, unless every 400.

Week days
Weekday names
#NameMeaningLock

Names from your language

Language: . Import a Seed from Toponym Forge to use your own sounds and roots; missing calendar roots (seasons, numbers, gods, weather…) are coined from its phonology and added to the Seed.

Moons
Moons
NamePeriod (days)Offset (age on year 1, day 1)Colour

Save & export

Free: 1 saved calendar in this browser (saving replaces it), JSON export and a printable year view. Your work also autosaves as a draft.

Forge Pro — coming soon: Not available yet. Subscribe below to hear when it is.

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