Date Difference Calculator
Calculate the exact number of days, weeks, months, years, and working weekdays between two calendar dates.
Client-side calculations and instant parameter controls are initializing. All processing occurs securely in your browser.
How to Use the Date Difference Calculator
- 1 Select a start date and an end date.
- 2 Optionally check "Include end date" to count the full duration inclusively.
- 3 View total calendar days, weeks, working weekdays, and equivalent year/month/day breakdown.
Mathematical Formula & Principle
Difference = End Date (UTC ms) − Start Date (UTC ms)
Calculations are performed with IEEE floating point mathematical precision directly in your device memory.
Worked Examples
Month Duration
Accurately measures calendar intervals excluding or including edge dates.
Frequently Asked Questions
- Does this calculator exclude weekends for business days?
- Yes, it separates total duration into working weekdays (Monday–Friday) and weekend days (Saturday–Sunday).
- What does "Include end date" mean?
- Standard date subtraction counts the nights between dates (e.g., Monday to Tuesday is 1 day). Checking "Include end date" counts both boundary days (2 days).
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