diff --git a/src/index.ts b/src/index.ts
index 41871d9..d6d1b5b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,6 +3,7 @@ import { eventBus } from './core/EventBus.js';
 import { calendarConfig } from './core/CalendarConfig.js';
 import { CalendarTypeFactory } from './factories/CalendarTypeFactory.js';
 import { ManagerFactory } from './factories/ManagerFactory.js';
+import { DateCalculator } from './utils/DateCalculator.js';
 
 /**
  * Initialize the calendar application with simple direct calls
@@ -13,6 +14,9 @@ async function initializeCalendar(): Promise<void> {
     // Use the singleton calendar configuration
     const config = calendarConfig;
     
+    // Initialize DateCalculator with config first
+    DateCalculator.initialize(config);
+    
     // Initialize the CalendarTypeFactory before creating managers
     CalendarTypeFactory.initialize();
     
diff --git a/src/managers/CalendarManager.ts b/src/managers/CalendarManager.ts
index 999cc4c..0200175 100644
--- a/src/managers/CalendarManager.ts
+++ b/src/managers/CalendarManager.ts
@@ -41,7 +41,8 @@ export class CalendarManager {
         this.eventRenderer = eventRenderer;
         this.scrollManager = scrollManager;
         this.eventFilterManager = new EventFilterManager();
-        this.dateCalculator = new DateCalculator(config);
+        DateCalculator.initialize(config);
+        this.dateCalculator = new DateCalculator();
         this.setupEventListeners();
     }
 
@@ -434,10 +435,10 @@ export class CalendarManager {
         const lastDate = new Date(lastDateStr);
         
         // Calculate week number from first date
-        const weekNumber = this.dateCalculator.getWeekNumber(firstDate);
+        const weekNumber = DateCalculator.getWeekNumber(firstDate);
         
         // Format date range
-        const dateRange = this.dateCalculator.formatDateRange(firstDate, lastDate);
+        const dateRange = DateCalculator.formatDateRange(firstDate, lastDate);
         
         // Emit week info update
         this.eventBus.emit(CoreEvents.WEEK_CHANGED, {
diff --git a/src/managers/NavigationManager.ts b/src/managers/NavigationManager.ts
index 9e0784c..90e8cc2 100644
--- a/src/managers/NavigationManager.ts
+++ b/src/managers/NavigationManager.ts
@@ -23,9 +23,10 @@ export class NavigationManager {
 
   constructor(eventBus: IEventBus, eventRenderer: EventRenderingService) {
     this.eventBus = eventBus;
-    this.dateCalculator = new DateCalculator(calendarConfig);
+    DateCalculator.initialize(calendarConfig);
+    this.dateCalculator = new DateCalculator();
     this.navigationRenderer = new NavigationRenderer(eventBus, calendarConfig, eventRenderer);
-    this.currentWeek = this.dateCalculator.getISOWeekStart(new Date());
+    this.currentWeek = DateCalculator.getISOWeekStart(new Date());
     this.targetWeek = new Date(this.currentWeek);
     this.init();
   }
@@ -135,7 +136,7 @@ export class NavigationManager {
 
   private navigateToToday(): void {
     const today = new Date();
-    const todayWeekStart = this.dateCalculator.getISOWeekStart(today);
+    const todayWeekStart = DateCalculator.getISOWeekStart(today);
     
     // Reset to today
     this.targetWeek = new Date(todayWeekStart);
@@ -153,7 +154,7 @@ export class NavigationManager {
   }
 
   private navigateToDate(date: Date): void {
-    const weekStart = this.dateCalculator.getISOWeekStart(date);
+    const weekStart = DateCalculator.getISOWeekStart(date);
     this.targetWeek = new Date(weekStart);
     
     const currentTime = this.currentWeek.getTime();
@@ -247,9 +248,9 @@ export class NavigationManager {
   }
 
   private updateWeekInfo(): void {
-    const weekNumber = this.dateCalculator.getWeekNumber(this.currentWeek);
-    const weekEnd = this.dateCalculator.addDays(this.currentWeek, 6);
-    const dateRange = this.dateCalculator.formatDateRange(this.currentWeek, weekEnd);
+    const weekNumber = DateCalculator.getWeekNumber(this.currentWeek);
+    const weekEnd = DateCalculator.addDays(this.currentWeek, 6);
+    const dateRange = DateCalculator.formatDateRange(this.currentWeek, weekEnd);
     
     // Notify other managers about week info update - DOM manipulation should happen via events
     this.eventBus.emit(CoreEvents.WEEK_CHANGED, {
diff --git a/src/managers/WorkHoursManager.ts b/src/managers/WorkHoursManager.ts
index 1aa8288..e379a67 100644
--- a/src/managers/WorkHoursManager.ts
+++ b/src/managers/WorkHoursManager.ts
@@ -39,7 +39,8 @@ export class WorkHoursManager {
 
   constructor(config: CalendarConfig) {
     this.config = config;
-    this.dateCalculator = new DateCalculator(config);
+    DateCalculator.initialize(config);
+    this.dateCalculator = new DateCalculator();
     
     // Default work schedule - will be loaded from JSON later
     this.workSchedule = {
@@ -64,7 +65,7 @@ export class WorkHoursManager {
    * Get work hours for a specific date
    */
   getWorkHoursForDate(date: Date): DayWorkHours | 'off' {
-    const dateString = this.dateCalculator.formatISODate(date);
+    const dateString = DateCalculator.formatISODate(date);
     
     // Check for date-specific override first
     if (this.workSchedule.dateOverrides[dateString]) {
@@ -83,7 +84,7 @@ export class WorkHoursManager {
     const workHoursMap = new Map<string, DayWorkHours | 'off'>();
     
     dates.forEach(date => {
-      const dateString = this.dateCalculator.formatISODate(date);
+      const dateString = DateCalculator.formatISODate(date);
       const workHours = this.getWorkHoursForDate(date);
       workHoursMap.set(dateString, workHours);
     });
diff --git a/src/renderers/ColumnRenderer.ts b/src/renderers/ColumnRenderer.ts
index 4317736..f9fae00 100644
--- a/src/renderers/ColumnRenderer.ts
+++ b/src/renderers/ColumnRenderer.ts
@@ -32,17 +32,18 @@ export class DateColumnRenderer implements ColumnRenderer {
     const { currentWeek, config } = context;
     
     // Initialize date calculator and work hours manager
-    this.dateCalculator = new DateCalculator(config);
+    DateCalculator.initialize(config);
+    this.dateCalculator = new DateCalculator();
     this.workHoursManager = new WorkHoursManager(config);
     
-    const dates = this.dateCalculator.getWorkWeekDates(currentWeek);
+    const dates = DateCalculator.getWorkWeekDates(currentWeek);
     const dateSettings = config.getDateViewSettings();
     const daysToShow = dates.slice(0, dateSettings.weekDays);
     
 
     daysToShow.forEach((date) => {
       const column = document.createElement('swp-day-column');
-      (column as any).dataset.date = this.dateCalculator.formatISODate(date);
+      (column as any).dataset.date = DateCalculator.formatISODate(date);
       
       // Apply work hours styling
       this.applyWorkHoursToColumn(column, date);
diff --git a/src/renderers/EventRenderer.ts b/src/renderers/EventRenderer.ts
index 2c00be1..aeac023 100644
--- a/src/renderers/EventRenderer.ts
+++ b/src/renderers/EventRenderer.ts
@@ -28,7 +28,10 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
 
   constructor(config: CalendarConfig, dateCalculator?: DateCalculator) {
     this.config = config;
-    this.dateCalculator = dateCalculator || new DateCalculator(config);
+    if (!dateCalculator) {
+      DateCalculator.initialize(config);
+    }
+    this.dateCalculator = dateCalculator || new DateCalculator();
   }
   
   /**
@@ -628,7 +631,7 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
   private calculateEventGridSpan(event: CalendarEvent, dateToColumnMap: Map<string, number>): { startColumn: number, columnSpan: number } {
     const startDate = new Date(event.start);
     const endDate = new Date(event.end);
-    const startDateKey = this.dateCalculator.formatISODate(startDate);
+    const startDateKey = DateCalculator.formatISODate(startDate);
     const startColumn = dateToColumnMap.get(startDateKey);
     
     if (!startColumn) {
@@ -641,7 +644,7 @@ export abstract class BaseEventRenderer implements EventRendererStrategy {
     
     while (currentDate <= endDate) {
       currentDate.setDate(currentDate.getDate() + 1);
-      const dateKey = this.dateCalculator.formatISODate(currentDate);
+      const dateKey = DateCalculator.formatISODate(currentDate);
       const col = dateToColumnMap.get(dateKey);
       if (col) {
         endColumn = col;
@@ -696,7 +699,7 @@ export class DateEventRenderer extends BaseEventRenderer {
 
     const columnEvents = events.filter(event => {
       const eventDate = new Date(event.start);
-      const eventDateStr = this.dateCalculator.formatISODate(eventDate);
+      const eventDateStr = DateCalculator.formatISODate(eventDate);
       const matches = eventDateStr === columnDate;
       
       
diff --git a/src/renderers/HeaderRenderer.ts b/src/renderers/HeaderRenderer.ts
index 9f1eaa2..54dc452 100644
--- a/src/renderers/HeaderRenderer.ts
+++ b/src/renderers/HeaderRenderer.ts
@@ -256,25 +256,26 @@ export class DateHeaderRenderer extends BaseHeaderRenderer {
     const { currentWeek, config } = context;
     
     // Initialize date calculator with config
-    this.dateCalculator = new DateCalculator(config);
+    DateCalculator.initialize(config);
+    this.dateCalculator = new DateCalculator();
     
-    const dates = this.dateCalculator.getWorkWeekDates(currentWeek);
+    const dates = DateCalculator.getWorkWeekDates(currentWeek);
     const weekDays = config.getDateViewSettings().weekDays;
     const daysToShow = dates.slice(0, weekDays);
 
     daysToShow.forEach((date, index) => {
       const header = document.createElement('swp-day-header');
-      if (this.dateCalculator.isToday(date)) {
+      if (DateCalculator.isToday(date)) {
         (header as any).dataset.today = 'true';
       }
       
-      const dayName = this.dateCalculator.getDayName(date, 'short');
+      const dayName = DateCalculator.getDayName(date, 'short');
       
       header.innerHTML = `
         <swp-day-name>${dayName}</swp-day-name>
         <swp-day-date>${date.getDate()}</swp-day-date>
       `;
-      (header as any).dataset.date = this.dateCalculator.formatISODate(date);
+      (header as any).dataset.date = DateCalculator.formatISODate(date);
       
       calendarHeader.appendChild(header);
     });
diff --git a/src/renderers/NavigationRenderer.ts b/src/renderers/NavigationRenderer.ts
index 60efdfd..19f6edb 100644
--- a/src/renderers/NavigationRenderer.ts
+++ b/src/renderers/NavigationRenderer.ts
@@ -24,7 +24,8 @@ export class NavigationRenderer {
     this.eventBus = eventBus;
     this.config = config;
     this.eventRenderer = eventRenderer;
-    this.dateCalculator = new DateCalculator(config);
+    DateCalculator.initialize(config);
+    this.dateCalculator = new DateCalculator();
     this.setupEventListeners();
   }
 
@@ -127,7 +128,7 @@ export class NavigationRenderer {
    * Render a complete container with content and events
    */
   public renderContainer(parentContainer: HTMLElement, weekStart: Date): HTMLElement {
-    const weekEnd = this.dateCalculator.addDays(weekStart, 6);
+    const weekEnd = DateCalculator.addDays(weekStart, 6);
     
     
     // Create new grid container
@@ -179,22 +180,22 @@ export class NavigationRenderer {
     dayColumns.innerHTML = '';
 
     // Get dates using DateCalculator
-    const dates = this.dateCalculator.getWorkWeekDates(weekStart);
+    const dates = DateCalculator.getWorkWeekDates(weekStart);
     
     // Render headers for target week
     dates.forEach((date, i) => {
       const headerElement = document.createElement('swp-day-header');
-      if (this.dateCalculator.isToday(date)) {
+      if (DateCalculator.isToday(date)) {
         headerElement.dataset.today = 'true';
       }
       
-      const dayName = this.dateCalculator.getDayName(date, 'short');
+      const dayName = DateCalculator.getDayName(date, 'short');
       
       headerElement.innerHTML = `
         <swp-day-name>${dayName}</swp-day-name>
         <swp-day-date>${date.getDate()}</swp-day-date>
       `;
-      headerElement.dataset.date = this.dateCalculator.formatISODate(date);
+      headerElement.dataset.date = DateCalculator.formatISODate(date);
       
       header.appendChild(headerElement);
     });
@@ -209,7 +210,7 @@ export class NavigationRenderer {
     // Render day columns for target week
     dates.forEach(date => {
       const column = document.createElement('swp-day-column');
-      column.dataset.date = this.dateCalculator.formatISODate(date);
+      column.dataset.date = DateCalculator.formatISODate(date);
       
       const eventsLayer = document.createElement('swp-events-layer');
       column.appendChild(eventsLayer);
diff --git a/src/strategies/MonthViewStrategy.ts b/src/strategies/MonthViewStrategy.ts
index 5c8b71c..c73642f 100644
--- a/src/strategies/MonthViewStrategy.ts
+++ b/src/strategies/MonthViewStrategy.ts
@@ -11,7 +11,8 @@ export class MonthViewStrategy implements ViewStrategy {
   private dateCalculator: DateCalculator;
   
   constructor() {
-    this.dateCalculator = new DateCalculator(calendarConfig);
+    DateCalculator.initialize(calendarConfig);
+    this.dateCalculator = new DateCalculator();
   }
   
   getLayoutConfig(): ViewLayoutConfig {
@@ -72,7 +73,7 @@ export class MonthViewStrategy implements ViewStrategy {
     dates.forEach(date => {
       const cell = document.createElement('div');
       cell.className = 'month-day-cell';
-      cell.dataset.date = this.dateCalculator.formatISODate(date);
+      cell.dataset.date = DateCalculator.formatISODate(date);
       cell.style.border = '1px solid #e0e0e0';
       cell.style.minHeight = '100px';
       cell.style.padding = '4px';
@@ -86,7 +87,7 @@ export class MonthViewStrategy implements ViewStrategy {
       dayNumber.style.marginBottom = '4px';
       
       // Check if today
-      if (this.dateCalculator.isToday(date)) {
+      if (DateCalculator.isToday(date)) {
         dayNumber.style.color = '#1976d2';
         cell.style.backgroundColor = '#f5f5f5';
       }
@@ -101,12 +102,12 @@ export class MonthViewStrategy implements ViewStrategy {
     const firstOfMonth = new Date(monthDate.getFullYear(), monthDate.getMonth(), 1);
     
     // Get Monday of the week containing first day
-    const startDate = this.dateCalculator.getISOWeekStart(firstOfMonth);
+    const startDate = DateCalculator.getISOWeekStart(firstOfMonth);
     
     // Generate 42 days (6 weeks)
     const dates: Date[] = [];
     for (let i = 0; i < 42; i++) {
-      dates.push(this.dateCalculator.addDays(startDate, i));
+      dates.push(DateCalculator.addDays(startDate, i));
     }
     
     return dates;
@@ -141,10 +142,10 @@ export class MonthViewStrategy implements ViewStrategy {
     const firstOfMonth = new Date(baseDate.getFullYear(), baseDate.getMonth(), 1);
     
     // Get Monday of the week containing first day
-    const startDate = this.dateCalculator.getISOWeekStart(firstOfMonth);
+    const startDate = DateCalculator.getISOWeekStart(firstOfMonth);
     
     // End date is 41 days after start (42 total days)
-    const endDate = this.dateCalculator.addDays(startDate, 41);
+    const endDate = DateCalculator.addDays(startDate, 41);
     
     return {
       startDate,
diff --git a/src/strategies/WeekViewStrategy.ts b/src/strategies/WeekViewStrategy.ts
index 6ac9957..ce22e28 100644
--- a/src/strategies/WeekViewStrategy.ts
+++ b/src/strategies/WeekViewStrategy.ts
@@ -15,7 +15,8 @@ export class WeekViewStrategy implements ViewStrategy {
   private styleManager: GridStyleManager;
   
   constructor() {
-    this.dateCalculator = new DateCalculator(calendarConfig);
+    DateCalculator.initialize(calendarConfig);
+    this.dateCalculator = new DateCalculator();
     this.gridRenderer = new GridRenderer(calendarConfig);
     this.styleManager = new GridStyleManager(calendarConfig);
   }
@@ -42,28 +43,28 @@ export class WeekViewStrategy implements ViewStrategy {
   }
   
   getNextPeriod(currentDate: Date): Date {
-    return this.dateCalculator.addWeeks(currentDate, 1);
+    return DateCalculator.addWeeks(currentDate, 1);
   }
   
   getPreviousPeriod(currentDate: Date): Date {
-    return this.dateCalculator.addWeeks(currentDate, -1);
+    return DateCalculator.addWeeks(currentDate, -1);
   }
   
   getPeriodLabel(date: Date): string {
-    const weekStart = this.dateCalculator.getISOWeekStart(date);
-    const weekEnd = this.dateCalculator.addDays(weekStart, 6);
-    const weekNumber = this.dateCalculator.getWeekNumber(date);
+    const weekStart = DateCalculator.getISOWeekStart(date);
+    const weekEnd = DateCalculator.addDays(weekStart, 6);
+    const weekNumber = DateCalculator.getWeekNumber(date);
     
-    return `Week ${weekNumber}: ${this.dateCalculator.formatDateRange(weekStart, weekEnd)}`;
+    return `Week ${weekNumber}: ${DateCalculator.formatDateRange(weekStart, weekEnd)}`;
   }
   
   getDisplayDates(baseDate: Date): Date[] {
-    return this.dateCalculator.getWorkWeekDates(baseDate);
+    return DateCalculator.getWorkWeekDates(baseDate);
   }
   
   getPeriodRange(baseDate: Date): { startDate: Date; endDate: Date } {
-    const weekStart = this.dateCalculator.getISOWeekStart(baseDate);
-    const weekEnd = this.dateCalculator.addDays(weekStart, 6);
+    const weekStart = DateCalculator.getISOWeekStart(baseDate);
+    const weekEnd = DateCalculator.addDays(weekStart, 6);
     
     return {
       startDate: weekStart,
diff --git a/src/utils/DateCalculator.ts b/src/utils/DateCalculator.ts
index 26e061a..2b51f1d 100644
--- a/src/utils/DateCalculator.ts
+++ b/src/utils/DateCalculator.ts
@@ -6,10 +6,14 @@
 import { CalendarConfig } from '../core/CalendarConfig';
 
 export class DateCalculator {
-  private config: CalendarConfig;
+  private static config: CalendarConfig;
   
-  constructor(config: CalendarConfig) {
-    this.config = config;
+  /**
+   * Initialize DateCalculator with configuration
+   * @param config - Calendar configuration
+   */
+  static initialize(config: CalendarConfig): void {
+    DateCalculator.config = config;
   }
 
   /**
@@ -18,7 +22,7 @@ export class DateCalculator {
    * @param methodName - Name of calling method for error messages
    * @throws Error if date is invalid
    */
-  private validateDate(date: Date, methodName: string): void {
+  private static validateDate(date: Date, methodName: string): void {
     if (!date || !(date instanceof Date) || isNaN(date.getTime())) {
       throw new Error(`${methodName}: Invalid date provided - ${date}`);
     }
@@ -29,14 +33,14 @@ export class DateCalculator {
    * @param weekStart - Any date in the week
    * @returns Array of dates for the configured work days
    */
-  getWorkWeekDates(weekStart: Date): Date[] {
-    this.validateDate(weekStart, 'getWorkWeekDates');
+  static getWorkWeekDates(weekStart: Date): Date[] {
+    DateCalculator.validateDate(weekStart, 'getWorkWeekDates');
     
     const dates: Date[] = [];
-    const workWeekSettings = this.config.getWorkWeekSettings();
+    const workWeekSettings = DateCalculator.config.getWorkWeekSettings();
     
     // Always use ISO week start (Monday)
-    const mondayOfWeek = this.getISOWeekStart(weekStart);
+    const mondayOfWeek = DateCalculator.getISOWeekStart(weekStart);
     
     // Calculate dates for each work day using ISO numbering
     workWeekSettings.workDays.forEach(isoDay => {
@@ -55,8 +59,8 @@ export class DateCalculator {
    * @param date - Any date in the week
    * @returns The Monday of the ISO week
    */
-  getISOWeekStart(date: Date): Date {
-    this.validateDate(date, 'getISOWeekStart');
+  static getISOWeekStart(date: Date): Date {
+    DateCalculator.validateDate(date, 'getISOWeekStart');
     
     const monday = new Date(date);
     const currentDay = monday.getDay();
@@ -72,10 +76,10 @@ export class DateCalculator {
    * @param date - Any date in the week
    * @returns The end date of the ISO week (Sunday)
    */
-  getWeekEnd(date: Date): Date {
-    this.validateDate(date, 'getWeekEnd');
+  static getWeekEnd(date: Date): Date {
+    DateCalculator.validateDate(date, 'getWeekEnd');
     
-    const weekStart = this.getISOWeekStart(date);
+    const weekStart = DateCalculator.getISOWeekStart(date);
     const weekEnd = new Date(weekStart);
     weekEnd.setDate(weekStart.getDate() + 6);
     weekEnd.setHours(23, 59, 59, 999);
@@ -87,7 +91,7 @@ export class DateCalculator {
    * @param date - The date to get week number for
    * @returns Week number (1-53)
    */
-  getWeekNumber(date: Date): number {
+  static getWeekNumber(date: Date): number {
     const d = new Date(Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()));
     const dayNum = d.getUTCDay() || 7;
     d.setUTCDate(d.getUTCDate() + 4 - dayNum);
@@ -102,7 +106,7 @@ export class DateCalculator {
    * @param options - Formatting options
    * @returns Formatted date range string
    */
-  formatDateRange(
+  static formatDateRange(
     start: Date, 
     end: Date, 
     options: {
@@ -137,7 +141,7 @@ export class DateCalculator {
    * @param date - Date to format
    * @returns ISO date string
    */
-  formatISODate(date: Date): string {
+  static formatISODate(date: Date): string {
     return `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`;
   }
 
@@ -146,7 +150,7 @@ export class DateCalculator {
    * @param date - Date to check
    * @returns True if the date is today
    */
-  isToday(date: Date): boolean {
+  static isToday(date: Date): boolean {
     const today = new Date();
     return date.toDateString() === today.toDateString();
   }
@@ -157,7 +161,7 @@ export class DateCalculator {
    * @param days - Number of days to add (can be negative)
    * @returns New date
    */
-  addDays(date: Date, days: number): Date {
+  static addDays(date: Date, days: number): Date {
     const result = new Date(date);
     result.setDate(result.getDate() + days);
     return result;
@@ -169,8 +173,8 @@ export class DateCalculator {
    * @param weeks - Number of weeks to add (can be negative)
    * @returns New date
    */
-  addWeeks(date: Date, weeks: number): Date {
-    return this.addDays(date, weeks * 7);
+  static addWeeks(date: Date, weeks: number): Date {
+    return DateCalculator.addDays(date, weeks * 7);
   }
 
   /**
@@ -178,10 +182,10 @@ export class DateCalculator {
    * @param weekStart - Start of the week
    * @returns Array of 7 dates for the full week
    */
-  getFullWeekDates(weekStart: Date): Date[] {
+  static getFullWeekDates(weekStart: Date): Date[] {
     const dates: Date[] = [];
     for (let i = 0; i < 7; i++) {
-      dates.push(this.addDays(weekStart, i));
+      dates.push(DateCalculator.addDays(weekStart, i));
     }
     return dates;
   }
@@ -192,7 +196,7 @@ export class DateCalculator {
    * @param format - 'short' or 'long'
    * @returns Day name
    */
-  getDayName(date: Date, format: 'short' | 'long' = 'short'): string {
+  static getDayName(date: Date, format: 'short' | 'long' = 'short'): string {
     const formatter = new Intl.DateTimeFormat('en-US', {
       weekday: format
     });
@@ -204,7 +208,7 @@ export class DateCalculator {
    * @param date - Date to format
    * @returns Time string
    */
-  formatTime(date: Date): string {
+  static formatTime(date: Date): string {
     return `${String(date.getHours()).padStart(2, '0')}:${String(date.getMinutes()).padStart(2, '0')}`;
   }
 
@@ -213,7 +217,7 @@ export class DateCalculator {
    * @param date - Date to format
    * @returns 12-hour time string
    */
-  formatTime12(date: Date): string {
+  static formatTime12(date: Date): string {
     const hours = date.getHours();
     const minutes = date.getMinutes();
     const period = hours >= 12 ? 'PM' : 'AM';
@@ -227,7 +231,7 @@ export class DateCalculator {
    * @param minutes - Minutes since midnight
    * @returns Time string
    */
-  minutesToTime(minutes: number): string {
+  static minutesToTime(minutes: number): string {
     const hours = Math.floor(minutes / 60);
     const mins = minutes % 60;
     const period = hours >= 12 ? 'PM' : 'AM';
@@ -241,7 +245,7 @@ export class DateCalculator {
    * @param timeStr - Time string
    * @returns Minutes since midnight
    */
-  timeToMinutes(timeStr: string): number {
+  static timeToMinutes(timeStr: string): number {
     const [time] = timeStr.split('T').pop()!.split('.');
     const [hours, minutes] = time.split(':').map(Number);
     return hours * 60 + minutes;
@@ -252,7 +256,7 @@ export class DateCalculator {
    * @param date - Date or ISO string
    * @returns Minutes since midnight
    */
-  getMinutesSinceMidnight(date: Date | string): number {
+  static getMinutesSinceMidnight(date: Date | string): number {
     const d = typeof date === 'string' ? new Date(date) : date;
     return d.getHours() * 60 + d.getMinutes();
   }
@@ -263,7 +267,7 @@ export class DateCalculator {
    * @param end - End date or ISO string
    * @returns Duration in minutes
    */
-  getDurationMinutes(start: Date | string, end: Date | string): number {
+  static getDurationMinutes(start: Date | string, end: Date | string): number {
     const startDate = typeof start === 'string' ? new Date(start) : start;
     const endDate = typeof end === 'string' ? new Date(end) : end;
     return Math.floor((endDate.getTime() - startDate.getTime()) / 60000);
@@ -275,7 +279,7 @@ export class DateCalculator {
    * @param date2 - Second date
    * @returns True if same day
    */
-  isSameDay(date1: Date, date2: Date): boolean {
+  static isSameDay(date1: Date, date2: Date): boolean {
     return date1.toDateString() === date2.toDateString();
   }
 
@@ -285,15 +289,20 @@ export class DateCalculator {
    * @param end - End date or ISO string
    * @returns True if spans multiple days
    */
-  isMultiDay(start: Date | string, end: Date | string): boolean {
+  static isMultiDay(start: Date | string, end: Date | string): boolean {
     const startDate = typeof start === 'string' ? new Date(start) : start;
     const endDate = typeof end === 'string' ? new Date(end) : end;
-    return !this.isSameDay(startDate, endDate);
+    return !DateCalculator.isSameDay(startDate, endDate);
   }
 
+  // Legacy constructor for backward compatibility
+  constructor() {
+    // Empty constructor - all methods are now static
+  }
 }
 
-// Create singleton instance with config
+// Legacy factory function - deprecated, use static methods instead
 export function createDateCalculator(config: CalendarConfig): DateCalculator {
-  return new DateCalculator(config);
+  DateCalculator.initialize(config);
+  return new DateCalculator();
 }
\ No newline at end of file