A fully custom desktop calendar built for dungeon masters. Design your own months, moon cycles, seasons, and weather — then track every arc of your campaign in one beautiful place.
From moon cycles to weather systems — Cronos handles the details so you can focus on the story.
Define your own month names, day names, and week length. Create multiple calendars and switch between them instantly.
Add as many moons as your world needs. Set custom cycle lengths and reference dates — phases calculate automatically.
Jump-start with built-in presets for Forgotten Realms, the Elder Scrolls Tamrielic calendar, or a generic fantasy world.
Eight biome-specific weather tables generate rich atmospheric descriptions for each day your party travels.
Define seasons with colours and icons. Mark multi-day campaign arcs that render as continuous bars across the calendar grid.
Runs natively on macOS and Windows. All data is stored locally — no accounts, no cloud, no internet required.
Log how your party spends each hour of the day — travelling, resting, exploring, or crafting. A detailed time-of-day breakdown keeps your world feeling alive and consistent between sessions.
Whether you're running Forgotten Realms, a homebrew world, or a sci-fi campaign — Cronos adapts completely. Every calendar, event, and note lives in one clean, offline interface.
Free, open, and runs entirely on your machine. No subscriptions, no accounts, no cloud.
macOS 11 Big Sur or later · Windows 10 / 11 (64-bit) · Web App works in any modern browser
Also from Giant Mushroom Studio
Cronos is completely free and always will be. If it's made your sessions a little richer and you'd like to say thanks, buying me a coffee helps keep the project going.