Date Difference Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
The number of days between two dates is found by subtracting the start date from the end date. Between January 1 and January 8, 2026, 7 calendar days elapse, including 5 business days.
Explanation
This calculator gives three complementary readings of the gap between two dates: the total number of calendar days (every day, weekends included), the number of full weeks it represents, and the number of business days (Monday through Friday only, excluding Saturday and Sunday). The latter is useful for estimating a delivery time, an administrative processing period, or a number of working days between two deadlines. One convention worth knowing: the end date itself isn't counted in the business-day tally, exactly like counting hotel nights (Monday to the following Tuesday counts as one night, not two). This calculator doesn't account for public holidays, which vary by country and sometimes by region: the actual number of business days may therefore be slightly lower if holidays fall within the period.
Example: from January 1 to January 8, 2026
Inputs
Start date: January 1, 2026 (Thursday). End date: January 8, 2026 (Thursday).
Calculation
Calendar days = January 8 − January 1 = 7 days, i.e. 1 full week. Of these 7 days (Thursday through Wednesday), 5 fall on weekdays (Thursday, Friday, Monday, Tuesday, Wednesday) and 2 fall on the weekend (Saturday, Sunday).
Result
7 calendar days, 1 full week, and 5 business days elapse between these two dates.
Frequently asked questions
Why doesn't the number of business days equal calendar days × 5/7?
Because that ratio is only an average: the exact number of business days depends on where the weekends fall within the chosen period, not just its total length. Two 7-day periods can contain 4 or 5 business days depending on the day of the week they start on.
Are public holidays taken into account?
No, this calculator only excludes Saturdays and Sundays. Public holidays vary by country (and sometimes by region or industry), which would make the calculation unreliable without specifying a reference calendar. For a timeline that includes known holidays, subtract those days manually from the result.
Does the end date count as a business day?
No, it's excluded from the count, on the same principle as counting hotel nights or car rental days: Monday to the following Tuesday represents 1 business day (Monday), not 2. If you want to include the end date, add it manually to the result if it falls on a weekday.