Date Duration & Business Days

Date Difference & Working Days Studio Pro

Accurately compute calendar days, business working days (excluding weekends & statutory public holidays), detailed Years-Months-Days breakdown, and project deadline forecasting 100% Client-Side.

1. Start Date

2. End Date

Workweek:

Include end date (+1 day) Exclude VN statutory holidays

Exact Duration Breakdown

Total Calendar Days

weeks days

Working / Business Days

Excludes weekends & statutory holidays

Detailed Year - Month - Day Breakdown:

yrs, mos, days

Weekend Days

Holidays

Total Hours

Total Minutes

Forecast Project Deadline: Add or Subtract Days

Start / Base Date:

Operation & Quantity:

Count Mode:

Calculated Target Date Result

The Project Deadline Dilemma: Calendar Days vs Business Working Days

Whether executing commercial construction contracts with a 60-day deadline, guaranteeing 15-day IT SLA deliverables, or calculating statutory legal notice periods, confusing calendar days with business working days triggers expensive project overruns and breach-of-contract penalties.

Standard date difference websites merely subtract calendar timestamps. They critically ignore real-world workplace constraints: weekend schedules (Monday–Friday vs Monday–Saturday workweeks) and statutory public holidays where banking institutions, governmental registries, and corporate offices remain closed.

Date Difference & Business Days Studio Pro by PhuDuy Tools delivers enterprise-grade precision: custom 5-day or 6-day workweek toggles, automated statutory holiday exclusions, inclusive end-date handling, full Years-Months-Days breakdowns, and reverse deadline projection (adding/subtracting workdays) 100% Client-Side.

3 How to Calculate Date Duration & Working Days in 3 Steps

Set Start & End Dates

Select start and end dates via native calendar controls or quick buttons (Today, +7d, +30d, +90d).

Configure Workweek & Holidays

Choose between 5-day (Mon-Fri) or 6-day (Mon-Sat) schedules, toggle statutory holiday deductions and inclusive mode.

Review Results & Forecast Deadlines

Inspect business days, total calendar duration, and full Y-M-D conversion. Switch to Add/Subtract tab to calculate exact delivery deadlines.

Statutory Public Holidays Reference

Official statutory paid public holidays mandated by labor regulation:

Holiday Name	Calendar Date	Mandatory Days	Weekend Compensatory Policy
Tết Dương Lịch	01/01 Dương lịch	1 ngày	Nghỉ bù Thứ Hai nếu rơi vào cuối tuần
Tết Nguyên Đán (Âm lịch)	Cuối tháng Chạp đến mùng 4 Tết	5 ngày	Kéo dài 7 - 9 ngày do cộng ngày cuối tuần
Giỗ Tổ Hùng Vương	10/03 Âm lịch	1 ngày	Nghỉ bù vào ngày làm việc kế tiếp nếu trùng cuối tuần
Ngày Thống Nhất & Quốc Tế Lao Động	30/04 & 01/05 Dương lịch	2 ngày	Nghỉ liên tiếp 2 ngày liền kề, nghỉ bù nếu trùng cuối tuần
Lễ Quốc Khánh	02/09 & 1 ngày liền kề	2 ngày	Chính phủ thông báo ngày liền kề hàng năm

Why PhuDuy Tools Date Difference Calculator Outclasses Others

Exact Business Working Days

Differentiates valid working shifts from weekends, essential for project management, SLA delivery, and payroll calculations.

Add / Subtract Workday Forecasting

Add X business days to your project kickoff date to determine the exact delivery date, automatically skipping weekends and holidays.

Flexible 5-Day or 6-Day Workweeks

Adapt effortlessly between corporate 5-day schedules (Mon–Fri) and manufacturing or retail 6-day operations (Mon–Sat).

Inclusive End-Date Calculation

Align with statutory legal definitions by selecting whether the end date itself is counted or excluded from duration metrics.

Frequently Asked Questions on Date Intervals & Business Days

How does a business day differ from a calendar day? ▾

Calendar days include every consecutive 24-hour day from Monday through Sunday. Business working days strictly encompass standard operational days, excluding weekly rest days (weekends) and statutory official holidays.

How does the "Include End Date" (Inclusive Mode) setting work? ▾

Calculating duration from Monday to Wednesday without inclusive mode yields 2 elapsed days (Monday and Tuesday). Enabling inclusive mode counts the concluding Wednesday as well, resulting in 3 full days. This distinction is vital in payroll and contract warranties.

How do I model timelines if my company operates on Saturdays? ▾

Simply switch the workweek dropdown to "6 Days (Mon–Sat)". The algorithm automatically includes Saturdays as valid working days, excluding only Sundays.

How does Add/Subtract Days assist project managers? ▾

When contractual SLAs stipulate delivery in 30 business days, the engine steps day-by-day skipping weekends and holidays to pinpoint the exact delivery date and day of week.

Are my schedule parameters and contract dates securely private? ▾

100% Client-Side Privacy Guarantee. All date algorithms, holiday checks, and workday iterations execute purely in local browser memory with zero tracking.

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