Date Difference Calculator
Calculate the number of days, weeks, months, and years between two calendar dates.
Formula
Day difference uses UTC midnight normalization. Month and year breakdowns use calendar-aware counting.
Assumptions
- Dates are interpreted in UTC to avoid timezone drift.
- Month and year components use calendar boundaries.
Limitations
- Does not account for business days or holidays.
- Does not handle historical calendar reforms.
Worked example
Jan 1, 2026 to Jul 22, 2026
The difference is 202 days (end date exclusive), or 0 years, 6 months, and 21 days on the calendar breakdown.
Frequently asked questions
Are the start and end dates inclusive?
The day count is exclusive of the end date. For example, Jan 1 to Jan 3 counts as 2 calendar days. The year/month/day breakdown uses calendar boundaries between the earlier and later date.
How is this different from the Age or Business Days calculators?
This tool measures elapsed calendar days only. Use the Age Calculator for chronological age from a birth date, or the Business Days Calculator for weekday and holiday-aware counts.
Last reviewed: 2026-07-22
Category: Date & Time
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