Business Days Calculator

Pick a start date and an end date, and this calculator counts how many weekdays fall between them, Monday through Friday, counting both the start and the end date themselves. It also reports the plain calendar total and how many of those days landed on a weekend. The primary figure, business days, is the one to read for anything quoted in working days. The count runs entirely in your browser and updates the moment you change either date.

The seven-day week behind the count

Business days rest on a much older structure: the seven-day week. That cycle has no direct astronomical basis in the way a day or a year does, since nothing in the motion of the Earth marks off exactly seven of anything. Its origin is usually traced to Babylonian astronomy, itself built on an earlier Sumerian calendar, in which seven wandering bodies were visible to the naked eye against the fixed stars: the Sun, the Moon, and the five planets known to antiquity, namely Mercury, Venus, Mars, Jupiter and Saturn. Seven days also roughly matches the interval between the Moon's phases, since a lunar month of about 29 and a half days splits into four quarters of a little over seven days each.

The Romans carried the scheme forward, attaching a planetary deity to each day, and the seven-day planetary week spread across the empire between the first and third centuries of the common era, displacing an older eight-day market cycle whose days Roman calendars marked with the letters A to H. The two ran side by side for a time: a Pompeii inscription sets a column of nundinal market days beside a column of planetary days, and a graffito from the same town dates 6 February in the year 60 as dies Solis, the earliest known use of the planetary names. Those Roman names still show through: Saturday keeps Saturn, while English borrowed Germanic gods for most of the others. In the year 321, on an edict dated 7 March, the emperor Constantine declared dies Solis, the day of the Sun, an official day of rest on which city magistrates and workshops should pause, though he allowed farmers to keep working their fields. That single legally protected rest day is the distant ancestor of the modern weekend.

From one rest day to two

For most of recorded history the working week left only one day clear. The Jewish Sabbath, running from Friday sundown to nightfall on Saturday, is the oldest weekly day of rest still kept without a break, and Christian Europe kept Sunday. The two-day weekend, by contrast, is barely a century old. It grew in part out of religious accommodation: a New England cotton mill is commonly credited with adopting a five-day week in 1908 so its Jewish workers could keep the Sabbath, at which point running the plant on Sunday to satisfy Christian workers made little sense, and closing both days was the tidy answer. Labor organizing pushed the idea wider through the 1920s.

Ford Motor Company moved its factory workers to a five-day, forty-hour week from May 1926 and announced the change publicly that September, framing it both as rest for workers and as leisure in which they might spend their wages. Federal law then anchored the forty-hour figure. The Fair Labor Standards Act of 1938 capped the standard week at 44 hours to begin with, dropped it to 42 in October 1939 and to 40 from 24 October 1940. Note what the act does not say: it never names Saturday and Sunday, and the Department of Labor still points out that it requires no rest days and no premium for weekend work as such. It only makes hours past 40 in a week expensive. The Monday-to-Friday block this calculator counts is a custom hardened by that pricing rule, not a statutory definition.

How the days are counted

The tool steps through every calendar day from the start to the end and sorts each one into two buckets: a weekday (Monday to Friday) or a weekend day (Saturday or Sunday). Under ISO 8601, the international date standard, the days are numbered Monday = 1 through Sunday = 7, so the test is simply whether a day's number is 6 or 7. Calendars in the United States and Canada often print Sunday in the first column, but that is a display choice and does not change which two days are the weekend. Both endpoints are included, so a range that opens and closes on a weekday always counts at least those two days. Plenty of deadline rules run the other way and begin counting the day after the triggering event. Federal Rule of Civil Procedure 6(a)(1)(A) directs courts to exclude the day of the event that starts the period, and many contracts copy that habit. If that is the convention you need, subtract one from the business-day figure.

business days = total days − weekend days

The total is inclusive, so it works out as end − start + 1. Counting both ends matters. From a Monday to the following Monday is 8 calendar days, not 7, and 6 of them are business days.

There is a shortcut worth knowing if you ever count by hand. Because the pattern repeats every seven days, every whole week inside the range contributes exactly five business days. Take the inclusive total, divide by seven to get the number of complete weeks, multiply that by five, and then walk through only the leftover one to six days, checking each against the weekend. A 31-day span is four complete weeks, worth 20 business days, plus three extra days, and where those three land decides whether the final answer is 21, 22 or 23. A 31-day month can never drop below 21, because three consecutive days hold at most two weekend days, while a 28-day February is exactly four weeks and so always lands on 20.

A worked example

The defaults run from 1 July 2026 to 31 July 2026, a span of 31 calendar days. July 2026 contains four Saturdays (the 4th, 11th, 18th and 25th) and four Sundays (the 5th, 12th, 19th and 26th), so 8 days are weekend days. Subtracting leaves 31 − 8 = 23 business days. Because 1 July is a Wednesday and 31 July is a Friday, both endpoints are weekdays and both are counted, which is why this month sits at the very top of the usual monthly range of 20 to 23.

August 2026 makes the contrast plain. It is the same length, 31 days, but it opens on a Saturday, so it holds five Saturdays and five Sundays, 10 weekend days in all, and returns 21 business days. Two months of identical length, two business-day totals two days apart, which is the reason to count rather than estimate.

Public holidays are not subtracted

This is the one thing to watch. The calculator knows nothing about public holidays, so a bank holiday that lands on a Tuesday still counts as a business day here. Holidays are left out on purpose, because they differ by country and often by region:

• The United States sets federal holidays such as Independence Day and Thanksgiving, but individual states add their own.
• The United Kingdom uses bank holidays, and Scotland and Northern Ireland keep a different list from England and Wales.
• Canada legislates statutory holidays at both the federal and the provincial or territorial level, so the list changes as you cross a provincial border. In Australia the power sits with the states and territories, which declare their own public holidays around a core of days observed nationwide.

If your deadline depends on a specific holiday calendar, count the business days here first, then subtract any holidays that fall on a weekday inside the range.

Where the count gets used

Business-day counting drives a lot of everyday deadlines. Payment terms are the classic trap: an invoice marked net-30 means 30 calendar days from the invoice date, weekends included, not 30 business days, whereas "payable within 10 business days" is exactly what this tool measures. Shipping and delivery estimates are almost always quoted in business days, as are bank transfer clearing times, securities settlement windows, returns periods and contractual notice requirements. When someone promises something in five working days on a Thursday, the convention decides the answer. Counting that Thursday as the first day lands on the following Wednesday, five business days across a seven-day span. Starting the clock the next morning instead lands on the following Thursday, six business days by this tool's inclusive count. Set the start date to match whichever rule the contract uses, then read the business-day figure.

Frequently asked questions

Does the business days calculator include the start and end date?

Yes. Both the start date and the end date are counted whenever they fall on a weekday. From Monday 6 July to Friday 10 July 2026 that gives 5 business days, because all five days are included. If you want the gap between two dates instead, excluding the start, subtract one from the business-day figure.

How many working days are in a typical month?

It ranges from 20 to 23 depending on how the weekends fall. July 2026 has 23 business days across 31 calendar days, near the top of the range because the month opens on a Wednesday and ends on a Friday. A 28-day February usually has exactly 20.

Are public holidays counted as business days here?

Yes, this calculator counts every Monday-to-Friday day and does not remove holidays. A US federal holiday like Thanksgiving, always a Thursday, or a UK bank holiday that lands on a Monday still shows up in the business-day total. Count the range first, then subtract any holidays that fall on a weekday for your own country.

What is the difference between calendar days and business days for net-30 terms?

Net-30 invoice terms almost always mean 30 calendar days, not business days, so weekends are included. Over any 30-day stretch you lose roughly 8 to 10 days to weekends, which leaves about 20 to 22 business days. Always check whether a contract says calendar or business days, because the gap is more than a week.

How do I count business days across two different months?

Enter any start and end date and the calculator handles the month boundary for you. From Monday 27 July to Sunday 2 August 2026 it counts 5 business days out of 7 total, because only the closing Saturday and Sunday are weekend days. There is no limit on how many months or years the range can span.