Use this calculator to find total days between two dates, plus business days when you exclude weekends and/or US federal holidays (2026). It’s useful for contract deadlines, event countdowns, pregnancy timelines, and “age in days” style planning.
A days-between-dates calculator counts calendar days or business days between two dates for planning and deadlines.
How to Calculate Days Between Dates
- Select start date
- Select end date
- Choose calendar days or business days if available
- Account for inclusive vs exclusive counting
- Use the result for contracts, travel, or project timelines
The Days Between Dates Formula
Calendar difference inclusive/exclusive per settings; business days exclude weekends/holidays if configured
Where: symbols follow the inputs and conventions used in this calculator (principal, rates, terms, or units as labeled).
Real-World Example
From Jan 15 to Mar 1 spans 45 calendar days in a non–leap year segment.
Quick Reference
- How to calculate Days Between Dates?
- Select start date Select end date Choose calendar days or business days if available Account for inclusive vs exclusive counting Use the result for contracts, travel, or project timelines
- What is the formula for Days Between Dates?
- Calendar difference inclusive/exclusive per settings; business days exclude weekends/holidays if configured
- Can you give a real-world Days Between Dates example?
- From Jan 15 to Mar 1 spans 45 calendar days in a non–leap year segment.
📊 Did You Know?
2026 US Federal Holidays: New Year's Day (2026-01-01), MLK Day (2026-01-19), Presidents' Day (2026-02-16), Memorial Day (2026-05-25), Juneteenth (2026-06-19), Independence Day (2026-07-04), Labor Day (2026-09-07), Columbus Day (2026-10-12), Veterans Day (2026-11-11), Thanksgiving (2026-11-26), Christmas (2026-12-25). (US federal holidays, 2026)
How to Use This Calculator
- Pick a start date and an end date.
- Turn on “Exclude weekends” to count only weekdays.
- Turn on “Exclude US federal holidays (2026)” if your deadline excludes holidays too.
The Formula Explained
Days = |End Date − Start Date| in milliseconds converted to days
Business-day counts are computed by iterating through each day in the range and skipping weekends/holidays based on toggles.
Tips & What Your Results Mean
If you’re using the output for contracts or HR policies, confirm whether “days” means calendar days or business days. Many deadlines are calendar-based, while SLA and operational deadlines often use business days.
For countdowns (events, pregnancy tracking, project phases), total days is usually the clearest number. For staffing and billing timelines, business days can be more practical—especially when holidays create hidden schedule gaps.
Leap years and month lengths are the main sources of mistakes when people do date math manually. Using a calculator avoids “almost correct” answers that are off by one or two days.
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