Date Difference Calculator – Days, Weeks, Months & Years
Free date difference calculator. Compute exact days, weeks, business days, months and years between two dates. Inclusive/exclusive modes, holidays, and clear step-by-step method.
Date range
Enter ISO dates separated by commas or new lines. Holidays are excluded from business-day counts.
Total days
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Weeks + remainder
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-- remainder days
Calendar breakdown
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How to Use This Calculator
- Enter the start date using the calendar picker.
- Enter the end date that is on or after the start date.
- Choose inclusive (counts start and end) or exclusive (counts the days between).
- Optionally paste holiday dates (ISO format) to exclude them from business-day totals.
- Click Calculate or wait for the live update to see days, weeks, business days, and the years-months-days breakdown.
Methodology
We compute the calendar delta in accordance with the proleptic Gregorian calendar. The exclusive mode measures the whole days between the dates while the inclusive mode adds one day so that both start and end appear on the tally. Business days skip Saturdays and Sundays and also remove any user-listed holidays. Weeks are the integer division of total days by seven, and the remainder captures the leftover days.
Full original guide (expanded)
Why this calculator
- Accurate leap-year and month-length handling following ISO 8601.
- Business days with optional holiday exclusions.
- Accessible, mobile-first, and print-friendly experience.