How to Calculate Business Days Between Two Dates

"Delivery within 5 business days." "Payment terms: net 30 business days." "Project deadline: 15 working days from approval."

Business days show up constantly in contracts, shipping estimates, and project timelines. Counting them by hand means pulling up a calendar, crossing off weekends, remembering holidays, and hoping you did not miscount. For a 5-day estimate, that is manageable. For 30 or 60 business days, it is tedious and error-prone.

The Business Days Calculator does this instantly. Enter a start date and the number of business days, and it gives you the exact end date with weekends excluded. Or enter two dates to find out how many business days fall between them.

Why Business Days Are Not Just 'Weekdays'

Business days are weekdays minus public holidays. The distinction matters more than you might think. A period of "10 business days" starting on December 18 stretches much further into January than you would expect, because Christmas and New Year's holidays remove 2 to 4 additional days depending on your country.

The tricky part is that public holidays vary by country, state, and sometimes even city. The US has 11 federal holidays. Germany has 9 national holidays plus additional state-specific ones. If your calculation involves international business, you need to account for the holidays in the relevant jurisdiction.

For most calculations, excluding weekends gets you 90% of the way there. The Business Days Calculator handles weekends automatically. For critical deadlines (legal filings, contract terms), verify against your local holiday calendar manually.

Common Business Day Calculations

Net payment terms: "Net 30" means payment is due within 30 calendar days, not business days. But some contracts specify "30 business days," which is about 6 calendar weeks. Know which one your contract uses before planning cash flow.

Shipping estimates: When a carrier says "5 business days," they mean Monday through Friday, excluding holidays. An order placed on Thursday afternoon usually does not start counting until Friday or even Monday, depending on the carrier's cutoff time.

Project planning: If you promise a deliverable in "2 weeks," does that mean 10 business days or 14 calendar days? Clarifying this upfront prevents misunderstandings. Use the Delivery Date Calculator to set accurate expectations.

Legal deadlines: Court filings, regulatory submissions, and official notices often have deadlines counted in business days. Missing a legal deadline because you miscounted weekends is an expensive mistake.

HR and payroll: Notice periods ("two weeks' notice" is typically 10 business days), probation periods, and vacation accrual are often calculated in business days.

Calculating Business Days in Spreadsheets and Code

If you need business day calculations in a spreadsheet:

Excel/Google Sheets: The NETWORKDAYS function counts business days between two dates, automatically excluding weekends. It also accepts an optional holiday list: ` =NETWORKDAYS(A1, B1, holidays) ` Where holidays is a range containing your holiday dates.

WORKDAY does the reverse: given a start date and a number of business days, it returns the end date: ` =WORKDAY(A1, 15, holidays) `

JavaScript: There is no built-in business day function. You need to loop through dates and check each one: `javascript function addBusinessDays(start, days) { let current = new Date(start); let added = 0; while (added < days) { current.setDate(current.getDate() + 1); const day = current.getDay(); if (day !== 0 && day !== 6) added++; } return current; } `

Python: The numpy library has busday_count and busday_offset for business day arithmetic. The pandas library offers bdate_range for generating sequences of business dates.

For one-off calculations where you do not want to write code or set up a spreadsheet, the online Date Calculator handles the math in your browser.

Time Zone Considerations

Business day calculations get complicated when parties are in different time zones. If you are in New York and your supplier is in Tokyo, "the next business day" starts at different absolute times for each of you. A request sent at 5 PM Eastern on Friday arrives in Tokyo on Saturday morning, their time, which means it will not be processed until Monday.

For international business, establish a reference time zone in your contracts. Common choices are the sender's time zone, the receiver's time zone, or UTC. Specifying "within 5 business days, Eastern Time" removes ambiguity.

Also consider the overlap in working hours. If your business day is 9 AM to 5 PM Eastern and your partner's is 9 AM to 5 PM JST, the overlap is roughly 9 PM to 1 AM Eastern (morning in Tokyo). Communication and approvals that require responses from both sides effectively move at half speed because of the limited overlap window.

FAQ

Does Saturday count as a business day?

In most Western countries, no. Business days are Monday through Friday. However, in some Middle Eastern countries (UAE, Saudi Arabia), the business week runs Sunday through Thursday, and in parts of South Asia, Saturday is a half-working day. Check the convention for the specific country involved.

How do I handle half-day holidays?

Most business day calculations treat half-day holidays as full business days. A company might close at noon on December 24th, but it still counts as a business day for calculation purposes. If you need precision, specify "full business days" in your agreements.

What is the difference between 'business days' and 'working days'?

They are usually interchangeable. Both refer to weekdays excluding public holidays. Some organizations use "working days" to include Saturday as a half-day, but this is uncommon in most English-speaking business contexts. When in doubt, define the term in your contract.

How many business days are there in a year?

In a typical year with 52 weeks, there are 260 weekdays (52 x 5). Subtracting public holidays (typically 8-11 depending on the country), a standard year has about 249-252 business days. Leap years with an extra weekday add one more.