Reference formulas and worked examples below keep their stated units. Monetary examples use USD; dimensional examples use US customary units unless labeled otherwise. Metric calculator inputs are converted to these reference units before calculation. Choosing another currency does not convert example amounts or exchange money.
How to use this business day calculator
Count workdays between two dates, or move forward or backward from a starting date. Holidays are only excluded when you enter them; no country calendar is silently assumed.
How the calculation works
Counting mode first applies the start/end inclusion setting. Each remaining date is classified as a weekend, a custom exclusion, or a workday, in that order. Duplicate exclusions and holidays falling on an excluded weekend are not subtracted twice.
Offset mode moves one calendar date at a time in the selected direction, excluding the start. Only workdays consume the requested offset. An offset of zero returns the starting date even if it is not a workday.
All dates are evaluated at UTC midnight solely for date arithmetic. Clock times and daylight-saving shifts do not enter the calculation.
Worked example
September 21–25, 2026 is Monday through Friday. Including both endpoints with Saturday/Sunday excluded gives 5 business days. Adding September 23 to your exclusions gives 4. Adding 10 business days to September 21 with no custom exclusions gives October 5, 2026.
Limits and assumptions
No automatic national, regional, banking, school, or court holiday calendar. You choose the weekend and supply any holidays. Dates are limited to 1900–2100; counting ranges to 3,660 days and offsets to 2,600 workdays. Deadline rules may use different endpoint conventions. This is date arithmetic, not a legal deadline determination.
Frequently asked questions
Are public holidays automatically removed?
No. Paste the relevant dates in the exclusion field. This makes closures explicit and avoids treating one national or regional calendar as universal.
Is the starting date counted when adding days?
No. It is day zero. Adding one workday to a Friday with a Saturday/Sunday weekend returns Monday, unless Monday is in your exclusions.
Can I count backward?
Yes. Choose Add or subtract business days and enter a negative whole number. A zero offset leaves the date unchanged.
What if a holiday is also a weekend?
It is counted as a weekend once and does not subtract another workday. Duplicate holiday dates are also counted only once.
Can I check every included date?
Yes. Open the date-by-date breakdown or download the full valid calculation as CSV. The on-page table previews the first 100 rows for long ranges.