Date Add/Subtract Calculator

Calculate new dates by adding or subtracting specific time intervals. Easily compute future and past dates using days, weeks, months, or years for precise planning.

About Date Add/Subtract Calculator

Understanding Date Mathematics

Date calculations are essential for project planning, scheduling, and timeline management. The complexity comes from various calendar systems, business day conventions, and timezone considerations. This calculator helps you navigate these complexities while ensuring accurate results.

Calendar Systems

Gregorian Calendar Rules

• Years: 365 days (366 in leap years)
• Months: 28-31 days
• Weeks: 7 days
• Business Days: Monday-Friday
• Leap Year: ((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)

Key Challenges

Complex leap year calculations
Variable month lengths
Week boundary handling
Business day vs calendar day
International date line effects

Time Units and Conversions

Standard Calendar Units

Years: Gregorian, fiscal, academic, lunar
Months: Calendar, fiscal periods
Weeks: Standard 7-day, business week
Days: Calendar days, business days
Custom periods for specific needs

Business Calendar Components

Working days vs. holidays
Regional weekend patterns
Bank holidays
Fiscal year variations
International conventions

Business Applications

Project Management

Sprint planning and iterations
Project timeline development
Resource allocation periods
Milestone tracking
Gantt chart calculations

Financial Operations

Payment term calculations
Contract duration management
Interest accrual periods
Fiscal year planning
Trading day calculations

Common Edge Cases

Technical Considerations

Date object manipulation complexity
Timezone handling
DST transitions
Leap year edge cases
Month-end rules

Edge Cases

Date validity verification
Century/millennium handling
Historical dates
Future date projections
Calendar reform considerations

Learn More

Temporal Date/Time API Business Day Conventions