Date Calculator

A professional date and workday calculation tool that supports date projection, interval calculation, and workday statistics with a built-in global holiday database. Ideal for project management, shift scheduling, vacation planning, and other scenarios requiring precise date calculations.

Key Features

Bidirectional Date Projection

Two calculation modes for forward and backward date projection:

• Forward mode: Calculate the date N days into the future from a specified date
• Backward mode: Calculate the date N days into the past from a specified date

Perfect for calculating project deadlines, contract expiration dates, trial period end dates, and similar scenarios.

Date Interval Calculation

Enter start and end dates to automatically calculate:

• Total days: Calendar days
• Workdays: Actual working days excluding weekends
• Weekend days: Total Saturdays and Sundays within the period

Supports both forward and reverse date input with automatic calculation order adjustment.

Global Holiday Support

Includes a global holiday database covering statutory holidays from over 200 countries and regions, including:

• National holidays (e.g., Spring Festival, National Day)
• Regional holidays (e.g., state/province-specific holidays)
• Religious holidays (e.g., Christmas, Eid al-Fitr)
• Fixed and movable holidays (e.g., Easter)

When holiday mode is enabled, workday statistics automatically exclude statutory holidays for the selected region.

Three-Tier Region Selection

Provides country, state/province, and city selection with cascading menus:

1. Select country: Choose from over 200 countries
2. Select state/province: Some countries support state-level subdivision (e.g., USA, Canada, China)
3. Select city: Some regions support city-level subdivision

Holiday rules from different levels are automatically merged to ensure accurate results.

Intelligent Workday Calculation

Workday calculation logic:

• Basic mode: Excludes only Saturdays and Sundays
• Holiday mode: Excludes weekends and statutory holidays

Supports calculating long-term project cycles across years and months, automatically handling leap years and varying month lengths.

Use Cases

Project Management

Calculate actual project workdays, excluding weekends and holidays for accurate project timeline estimation. For example: A development task requires 20 workdays starting January 15, 2024. Considering the Spring Festival holiday, when will it actually be completed$1

Human Resources

Calculate employee probation periods, contract terms, annual leave days, etc. Supports calculation by calendar days or workdays to meet different policy requirements. For example: A 3-month probation period (90 days) from the hire date, or calculated as 60 workdays.

Financial Settlement

Calculate billing periods, payment cycles, interest calculation days, etc. Supports date projection accurate to the day, avoiding manual calculation errors.

Vacation Planning

Plan travel and vacation time, view the distribution of workdays and holidays during the period. Combined with holiday data, schedule vacations reasonably and avoid peak travel periods during statutory holidays.

Usage Examples

Calculate Project Deadline

Scenario: Starting March 1, 2024, 30 workdays are needed to complete development.

Steps:

1. Select "Calculate" mode
2. Enable "Calculate holidays" toggle
3. Select country "China"
4. Select date "2024-03-01"
5. Select "Forward" direction
6. Enter "30" days
7. View results:
   • End date: 2024-04-10
   • Total days: 40
   • Workdays: 30
   • Holidays: 10 (including Qingming Festival)

Calculate Remaining Annual Leave

Scenario: Employee used how many workdays of leave from January 1 to June 30, 2024.

Steps:

1. Select "Interval" mode
2. Enable "Calculate holidays" toggle
3. Select country and region
4. Start date: 2024-01-01
5. End date: 2024-06-30
6. View results:
   • Total days: 181
   • Workdays: approximately 124
   • Holidays: 57 (weekends + Spring Festival, Qingming, Labor Day, Dragon Boat Festival)

Cross-Border Project Collaboration

Scenario: Calculate common workdays for teams in China and the USA.

Steps:

1. Calculate workdays separately for both locations
2. Compare holiday differences (e.g., Chinese Spring Festival, American Thanksgiving)
3. Schedule international meetings and collaboration time
4. Avoid scheduling critical tasks during either country's holidays

Important Notes

Holiday Data Accuracy

Holiday data is regularly updated but may have delays. Temporary work adjustments and makeup workdays in some countries may not be updated promptly. For critical scenarios, verify against official announcements.

Region Selection

Some countries only support national-level holidays without state/province subdivision. Select the appropriate region level based on actual needs. The China region supports Taiwan holiday queries.

Workday Definition

Different countries and regions may have different workday definitions (e.g., some Middle Eastern countries have weekends on Friday-Saturday). This tool uses the international standard (Monday-Friday as workdays). Manual adjustments are needed for special cases.

Calculation Mode Differences

Day counting methods differ slightly between "Calculate" and "Interval" modes:

• Calculate mode: Projects specified days from the start date (excluding start date)
• Interval mode: Calculates days between two dates (including both start and end dates)

Choose the correct mode based on business requirements.

Comparison with Similar Tools

Compared to timeanddate.com, online date calculator websites, and similar tools, this tool offers:

1. Integrated global holiday data, no manual lookup needed
2. Three-tier region selection, supporting city-level holiday precision
3. Bidirectional calculation support, easy switching between forward and backward
4. Localized interface for intuitive operation
5. Real-time calculation display, no button clicking required
6. Pure front-end implementation with fast response

Ideal for project managers, HR professionals, and finance personnel who frequently need date and workday calculations.