Add Business Days to a Date
Updated: May 2026
When a deadline is expressed as "N business days from today," you need more than simple date arithmetic. Weekends and public holidays must be skipped automatically to land on the correct working day.
Use the Add Days mode to get your exact deadline date in seconds.
Open the Business Days Calculator →When you need to add business days
Many standard deadlines are expressed in business days rather than calendar days. This is intentional — it ensures the deadline always falls on a day when both parties can act. Common situations include:
- Invoice payment terms: Net-10 or Net-30 mean 10 or 30 business days, not 10 or 30 calendar days.
- Delivery commitments: "Dispatched within 3 business days" determines the expected ship date.
- Legal response deadlines: Administrative bodies often give 15 or 30 business days to respond.
- HR processes: Appeal windows, notice periods and probation review dates are calculated in working days.
- Project milestones: Sprint end dates in agile teams are counted in business days.
The algorithm behind the calculation
Adding N business days to a date is straightforward in principle: starting from the day after the start date, advance one calendar day at a time, counting only weekdays that are not holidays. Stop when N business days have been counted. The final day is your deadline.
The complexity arises from two edge cases. First, public holidays must be resolved to their observed dates — in the US, a holiday falling on Saturday is observed on Friday, and one falling on Sunday is observed on Monday. Second, holiday rules change from year to year: Easter is calculated algorithmically, and some governments add one-off bank holidays. Our tool uses rules-based generation to handle any year without hardcoded data.
Excel WORKDAY equivalent
Microsoft Excel users may know the WORKDAY(start_date, days, [holidays]) function, which does exactly this. Our calculator provides the same result online, with no spreadsheet needed. You can also subtract business days (negative direction) to find how far back you need to start — equivalent to WORKDAY(start_date, -N).
- Select "Add Days to a Date" mode.
- Enter your start date.
- Enter the number of business days.
- Choose the country holiday calendar that applies.
- Click Calculate to see the result date.
Counting backwards to find a start date
The backward direction is useful when you know the deadline and need to find the latest possible start date. For example, if a product must be delivered in 10 business days and today is the deadline, work backwards to find when production must begin. Toggle the direction to "Backward" in the tool and enter the deadline date as the start.
Cross-country calculations
When one party is in France and another is in the US, holidays differ. The tool lets you choose a single country calendar, or you can add holidays from multiple countries manually using the Custom Holidays option. For legal certainty, contracts should specify exactly which country's official holiday calendar governs deadline calculations.
Frequently asked questions
What is the equivalent of Excel WORKDAY online?
The Add Days mode in our calculator replicates Excel's WORKDAY function exactly. Enter a start date and a number of business days to get the end date, with weekends and holidays automatically skipped.
Can I subtract business days from a date?
Yes. Use the Backward direction to count backwards. This is useful to find the earliest date you must start a task to meet a known deadline.
Does it account for holidays at the end of the range?
Yes. If the calculated end date would fall on a holiday or weekend, the calculator continues until the next valid business day.