MSI-CAL-1.0
International Fixed Calendar

A calendar that never breaks: identical months, stable weekdays, and a civilization-scale scheduling grid aligned to the MSI epoch.

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Why the Calendar Matters

Variable month lengths, shifting weekdays, and patchwork conventions create hidden complexity in finance, logistics, education, and software. MSI-CAL defines a fixed annual structure so systems remain stable forever. The calendar is designed to eliminate irregular month lengths, drifting weekdays, and ad-hoc exceptions that complicate planning, accounting, and software systems.

MSI-CAL is built on a simple principle: if dates are permanent, coordination becomes easier at every scale. The same date always falls on the same weekday, year after year, generation after generation.

This stability supports long-term contracts, education schedules, fiscal planning, and recurring civil events without the need for perpetual recalculation.

Calendar Structure. 13 Months × 28 Days

The MSI-CAL year consists of 13 identical months, each containing 28 days. This produces a consistent 364-day grid aligned to weeks. Any additional adjustment days required for solar alignment are handled outside the weekly cycle, preserving the integrity of the calendar grid.

MSI-CAL-1.0 defines a 364-day on-grid year: every month is identical. The week never drifts across the calendar. Reset Day(s) sit outside the week to preserve permanence.

MonthPrimis
CodePR
Weeks4
Days28
Calendar visual
CALENDAR COMPARISON WIDGET
Gregorian ↔ MSI-CAL · Reset Days · Week Stability

Compare Systems

This mini-app will show how dates map from the legacy calendar to MSI-CAL, and how weekdays remain fixed year over year. (Placeholder here — implementation comes later.)

Where MSI-CAL Is Applied

MSI-CAL integrates with MSI-TIME and MSI-ZERO to align civil timekeeping to a unified reference epoch, enabling consistent global coordination.

  • Payroll, accounting, and fiscal period design
  • Logistics planning and recurring schedules
  • Education terms and civil planning
  • Software date arithmetic and reporting stability
Scheduling visual
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