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Business Days Calculator: Count Working Days

Enter your dates above and press Calculate.

What is this tool?

The business days calculator counts working days between two dates, excluding Saturdays and Sundays, and can also add a number of business days to a starting date. It is the tool for work deadlines, notice periods, delivery estimates and project planning, where calendar days would overstate the time available. Enter your dates below and the result shows business days and calendar days side by side, so the difference is always visible.

How it works

A business day is Monday to Friday. The count includes both the start and end dates when they are business days, and skips weekends entirely. Public holidays are not excluded, because holidays differ by country and year — if your span includes a public holiday, subtract one business day for each holiday in the span. The add-days tool below skips weekends the same way.

Worked example

Worked example: Monday 5 January 2026 to Friday 9 January 2026 is 5 business days, even though the calendar difference is only 4 days, because both end days count. Adding 5 business days to Monday 5 January 2026 gives Monday 12 January 2026, skipping the weekend.

When to use it

Counting working days matters whenever a deadline is set in working time rather than calendar time. A promise of delivery in ten working days is not the same as delivery in ten calendar days, because two weekends sit inside most ten-day calendar spans. The same distinction applies to notice periods, project schedules, hiring start dates, service windows and any agreement that says a reply, a payment or a piece of work is due within a stated number of working days. Using calendar days for such a commitment usually understates the time available, while using working days for a holiday or a trip usually overstates it, so the first step is always to check which unit the commitment actually uses.

Project planning is the most common everyday use. A task that needs twelve working days of effort cannot be fitted into twelve calendar days if the team does not work weekends, and a schedule built on calendar days will look finished on paper a few days before it can actually be finished in practice. Counting the working days first, then mapping them onto the calendar, gives a finish date that survives contact with real weekends. The same logic applies to personal planning: booking annual leave, arranging a house move, or setting a date for an event that depends on offices, banks or suppliers being open all depend on knowing which of the days in a span are working days and which are not.

There are also uses where the count itself is the answer rather than a step toward a date. Someone checking how many working days fall in a month, how many remain before a deadline, or how long a process that only runs on weekdays will take needs a single reliable number, not a rough estimate. A month with five Mondays is not the same as a month with four, and a span that starts on a Friday behaves very differently from one that starts on a Monday. The tool above handles those variations by walking the actual calendar instead of applying an average, which is why it stays accurate across month boundaries, short weeks and spans that begin or end on a weekend.

One boundary is worth stating plainly. This count treats Monday to Friday as working days and Saturday and Sunday as non-working days, and it does not remove public holidays, because holidays differ by country and by year. If a span includes a public holiday, subtract one from the result for each holiday that falls on a weekday inside the span. That manual adjustment keeps the result honest: a tool that silently guessed at holidays would be wrong for every reader in a different country, while a stated rule lets every reader adjust correctly for their own calendar.

Step by step

There are two calculations on this page, and each takes less than a minute. The first counts working days between two dates. The second adds a number of working days to a starting date. Both use the same definition of a working day, so the two results always agree with each other, and either one can be used to check the other.

  1. Enter the start date in the first pair of fields. This is the first day of the span you want to measure, for example the day a task begins or a notice period starts.
  2. Enter the end date in the second field. Both ends count when they fall on weekdays, so a span from a Monday to the Friday of the same week gives five, not four.
  3. Read the result, which shows the working-day count and the calendar-day count for the same span side by side. The comparison is useful: if the two numbers are close, the span contains few weekends; if they differ a lot, weekends make up a large part of it.
  4. If the span includes a public holiday on a weekday, subtract one for each such holiday. The result on screen does not do this for you, because no single holiday list fits every country.
  5. To find a future date instead, use the second pair of fields: enter a starting date and the number of working days to add. The result lands on a working day, skipping any weekends in between.
  6. Check the weekday shown with the result. If it falls on a Saturday or Sunday, something has gone wrong with the inputs, because the add-days calculation never lands on a weekend.

Reading the result well matters as much as entering the dates well. A count of twenty working days does not mean twenty calendar days, and it does not mean four calendar weeks either, unless the span happens to start on a Monday. A span of twenty working days that starts on a Wednesday runs for almost four calendar weeks, because it contains four weekends rather than three. The calendar-day figure shown next to the working-day figure exists to make that difference visible at a glance, and it is worth glancing at it before quoting either number to someone else.

For the add-days calculation, remember that the count starts from the day after the starting date. Adding one working day to a Friday gives the following Monday, not the Friday itself, and adding five working days to a Monday gives the Monday of the following week, not the Friday of the same week. That convention matches how deadlines are usually read: five working days from Monday means five working days of work after Monday, with the result falling on the fifth working day after the start. If your agreement counts the starting day itself, subtract one from the number you enter, and say so when you quote the date.

Common mistakes

The most frequent mistake is counting calendar days and calling them working days. Ten calendar days contain either eight or six working days depending on where the weekends fall, so a deadline quoted in working days and measured in calendar days will be wrong by two to four days in a typical fortnight. The error grows with longer spans: a month of thirty-one calendar days contains twenty-two working days at most, and fewer if it starts or ends awkwardly. Any plan built on the calendar count will therefore promise more working time than actually exists.

The second mistake is forgetting whether the ends of the span count. This page counts both ends when they are weekdays, which is the natural reading of a span from Monday to Friday: five days of work, not four. Other conventions exist, and the danger is mixing them up halfway through a calculation, for example counting both ends in one step and neither end in the next. Pick one convention, state it when the number matters, and use the same convention for every span in the same document or agreement.

A subtler mistake is assuming that every week contributes exactly five working days. A span that starts on a Wednesday and ends on a Tuesday of the following week contains seven working days, not five, because it takes in parts of two working weeks. The same effect appears at month boundaries: a span from late January into early February can contain working days from two different monthly totals, which is why adding monthly working-day figures together sometimes gives a different answer from counting the whole span at once. When a total matters, count the whole span in one calculation rather than adding up monthly pieces.

More worked examples and notes

The examples below all use the same counting rule as the tool above: both ends count when they fall on weekdays, weekends are skipped, and public holidays are not removed. Each one can be checked by entering the same dates into the tool.

Two patterns in these examples are worth remembering. First, adding a multiple of five working days to any starting date lands on the same weekday as the start, because five working days make exactly one working week. Adding ten or twenty working days therefore behaves like adding two or four weeks to the weekday, even though the calendar distance is longer. Second, the working-day count for a span depends on where the span starts, not just on its length: a ten-calendar-day span can contain six, seven or eight working days depending on how many weekends it takes in. That is the whole reason this calculation exists, and it is why a quick estimate based on dividing calendar days by seven and multiplying by five is only ever approximate.

For very long spans the same rule scales without change, but two practical points appear. Public holidays become harder to ignore over a span of months, because a long span will almost certainly contain several, and each one reduces the true working-day count by one. And the effect of the starting weekday washes out over long spans: over a full year the working-day total is close to five sevenths of the calendar total, whatever day the year starts on, because the partial weeks at the two ends become a small fraction of the whole. For short spans, though, the starting weekday is everything, and that is where careful counting pays off most.

Try also

Date Calculator →Days Between Dates Calculator →

Frequently asked questions

How many business days are between two dates?

Enter both dates above. The calculator counts Monday to Friday days including both ends, and shows the calendar-day count next to it for comparison.

Are Saturdays counted?

No. Saturdays and Sundays are excluded, which is the standard definition of a business day in most countries. If your workplace works Saturdays, use the calendar-day count instead.

How are public holidays handled?

They are not excluded automatically, because holidays vary by country. Subtract one business day for each public holiday inside your span, or check the holiday calendar for your country.

Business days in Excel with NETWORKDAYS?

Use =NETWORKDAYS(start, end) for weekdays only, or =NETWORKDAYS(start, end, holidays) with a holiday list. Excel's function excludes the same weekends this calculator does.

Written and checked against the calculator above. Last updated: 21 October 2026. Calculation runs entirely in your browser — no date is sent to a server. This tool gives calendar results only, not medical, legal or financial advice.