Calculator
Date Difference Calculator — Days Between Dates
- Calculate
- Mobile Friendly
- Accessibility Tested
- Formula Verified
- SEO Optimized
- Fast Loading
- Responsive
Version 1.0.0 · Last reviewed
How it worksShow guide
Introduction
Find the calendar span between two dates — years, months, and days — plus total days, hours, ISO-8601 duration, weekdays, and an inclusive working-day count. Optional times of day refine the hour and minute totals. Everything runs in your browser.
Formula
Absolute calendar difference between two dates in days, with Y/M/D breakdown.
- d1 — Start date
- d2 — End date
Step-by-step
- Pick the start and end dates (or swap them).
- Optionally include times of day.
- Choose a weekend pattern if you need working days.
Worked example
From 1 Jan 2024 to 1 Jan 2025 is exactly 1 year (366 calendar days because 2024 is a leap year).
Use cases
- Project duration between two milestones
- Count days until an event
- Estimate weekdays for leave or contractors
- Produce an ISO duration string for APIs
Frequently asked questions
What if end is before start?
The tool returns the absolute difference and notes that the order is inverted.
Are working days inclusive?
Yes. Monday through Friday in the same week counts as five working days. Custom holidays live on the dedicated Working Days calculator.
Does time of day change the calendar span?
Years, months, and days stay date-based. Hours and minutes use the optional times so an afternoon-to-morning span can be less than a full extra day in clock time.
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