🛠️ User Guide & Overview: Business Days Calculator

Need to accurately calculate project deadlines, international shipping lead times, contract expiration dates, or administrative processing periods? The Business Days Calculator is a convenient, automated, and precise tool designed to compute working days while accounting for custom work schedules and official public holidays worldwide—including Vietnam, Canada, the US, and over 20 other countries.

 1. Key Features

• 2 Flexible Calculation Modes:

  • Count Between Dates: Calculate the exact number of working days between any two dates.

  • Add/Subtract Days: Starting from a specific date, add or subtract $N$ business days to determine the exact target completion date.

• Customizable Work Schedules:

  • Saturday Schedule: Support for Day Off (0 days), Half Day (0.5 day), or Full Workday (1.0 day).

  • Sunday Schedule: Support for Day Off or Full Workday.

• Auto-Fetch Country Holidays (Live API):

  • Automatically fetches official public holiday data for over 20 popular countries (Vietnam, Canada, United States, Japan, United Kingdom, Australia, South Korea, Singapore, etc.) for any selected year so your data is never outdated.

• Custom Holiday List: Allows you to manually enter internal company holidays or custom days off.

• 1-Click Copy Result: Quickly copy formatted calculation summaries to share via email, Slack, or project management reports.

• 100% Cross-Platform Compatibility: Displays clearly on all operating systems (Windows, macOS, iOS, Android) without missing characters or broken emoji flags.

 2. Step-by-Step Guide

🔹 Scenario 1: Count Business Days Between Two Dates

Example: Calculate the total number of working days between March 1st and March 31st.

1. Select the Count Between Dates tab.

2. Choose your Start Date and End Date.

3. Check Include end date in calculation if you want the calculation to include the final date.

4. Adjust the Saturday / Sunday Schedule dropdowns to match your organization’s work week.

5. Under Auto-Fetch Country Holidays (API), select your target country (e.g., Canada or Vietnam) to automatically pull official holidays for the period.

6. Click Calculate Result.

🔹 Scenario 2: Add or Subtract Working Days

Example: A contract requires delivery 10 business days after May 15th. What is the target date?

1. Select the Add/Subtract Days tab.

2. Pick the Start Date.

3. Under Action, select Add (+) or Subtract (-).

4. Enter the Number of Working Days (e.g., 10 or 5.5).

5. Set up your work schedule and country holiday preferences as needed.

6. Click Calculate Result—the tool will return the exact target date along with the day of the week.

 3. Practical Applications

• Project Management: Build realistic project timelines, sprint milestones, and delivery deadlines.

• Logistics & International Trade: Determine accurate lead times for cross-border shipping and customs clearance (e.g., Vietnam ↔ Canada trade routes) while factoring in destination holidays.

• HR & Payroll: Calculate working days per month, probation periods, and leave allowances.

• Legal & Contracts: Ensure strict compliance with contractual deadlines defined in “business days.”