How to Calculate Working Days Between Two Dates

Delivery in "10 business days", a project due in 15 working days, a notice period measured in business days — these counts skip Saturdays and Sundays, which makes them trickier than plain calendar counts. The math itself is short; the care goes into handling the partial week at each end and subtracting holidays correctly.

This guide walks through the method that works for any date range, a worked example from November 2026, the holiday rules that trip people up, and how spreadsheets and calculators handle it.

What counts as a working day?

Unless a contract says otherwise, a working day(or "business day") is Monday through Friday. Two immediate consequences:

• A normal full year has 260 working days(365 days − 105 weekend days). 2026 is exactly that: 365 days, 260 working days before holidays.
• A 7-day calendar week always contains exactly 5 working days — which is the key to the shortcut below.

Public holidays are usually not automatically excluded — more on that in the holiday section, because this is where most wrong answers come from.

The method: full weeks first, then the remainder

Step 2 works because every complete 7-day stretch contains exactly one of each weekday. You only need to inspect the leftover partial week (0–6 days) against a calendar to see which of those are Mon–Fri.

Worked example: November 2 to November 30, 2026

November 2, 2026 is a Monday; November 30 is a Monday too. How many working days are in between (not counting the start, counting the end)?

• Calendar days:November 30 − November 2 = 28 days
• Full weeks:28 ÷ 7 = 4 exactly → 4 × 5 = 20 working days, no remainder to check

The answer is 20 working days. Now subtract holidays: Thanksgiving 2026 falls on Thursday, November 26 — inside the range and on a weekday — so the holiday-adjusted count is 19 (many workplaces also treat Friday the 27th as a day off, which would make it 18).

Worked example with a remainder: November 4 to December 25, 2026

How many working days from Wednesday, November 4 until Christmas, Friday, December 25, 2026?

• Calendar days: 51 (26 remaining in November + 25 in December)
• Full weeks:51 ÷ 7 = 7 remainder 2 → 7 × 5 = 35 working days
• Leftover 2 days:the span starts on a Wednesday, so the leftover days are a Wednesday and a Thursday — both working days → +2

Thanksgiving (Thu, Nov 26) falls inside the range, so the holiday-adjusted count is 36. Notice how the remainder step depends on the weekday of the start date— the same 51-day span starting on a Friday would have a different remainder (35 + 1: the two leftover days are a Friday, which counts, and a Saturday, which doesn't).

Holidays: the step that changes the answer

"Business days" and "working days" do not automatically exclude holidays — a Tuesday holiday still counts as a business day under the plain Mon–Fri definition. When a deadline matters, decide which rule applies:

• Contract/legal deadlines.Many jurisdictions push a deadline that lands on a weekend or holiday to the next business day. Check the document's definition section.
• Shipping and service promises.Usually exclude weekends only; holidays may or may not extend the window — retailer "10 business day" shipping commonly excludes the retailer's own holiday list.
• Project planning.Subtract every holiday your team actually takes. A US range spanning Thanksgiving week, Christmas, and New Year can lose 4–6 working days beyond weekends.

Only holidays falling Monday–Friday reduce the count. A holiday on a Saturday (like July 4, 2026) doesn't change a Mon–Fri count at all, though federal observance rules shift some of them to Fridays.

Counting forward: "N business days from today"

The reverse question — today is Wednesday, November 4, 2026; what date is 10 business days from now? — is a walk along the calendar:

• Thu 5, Fri 6 (2) · Mon 9, Tue 10, Wed 11, Thu 12, Fri 13 (7)
• Mon 16, Tue 17, Wed 18 — stop at 10 on Wednesday, November 18

A useful estimate: N business days ≈ N × 1.4 calendar days when starting from a Monday (10 business days ≈ 14 calendar days), but the exact date depends on where weekends fall — and the estimate silently breaks across holidays. For exact answers, the date calculator counts days between two dates with weekends excluded, and you can subtract holidays from its result.

How spreadsheets do it

Excel and Google Sheets have NETWORKDAYS(start, end, [holidays]), which counts Mon–Fri days inclusive of both endpointsand subtracts any holiday list you pass it. Two conventions to note:

• NETWORKDAYS counts both the start and end dates if they are weekdays — the manual method in this guide (start exclusive, end inclusive) will differ by 1 when the start date is a weekday.
• NETWORKDAYS.INTL lets you define which days are weekends (for example, Friday–Saturday weekends in the Middle East).

Common mistakes

• Using 5/7 of the calendar days blindly.51 × 5/7 = 36.4 — close to our 37 but wrong for short spans. A 3-day Friday–Sunday span has 0 or 1 working days, never "about 2".
• Forgetting that the remainder depends on the start weekday. Same length, different start day, different answer.
• Subtracting Saturday holidays.A holiday on a weekend doesn't reduce a Mon–Fri count (though its observed weekday shift might).
• Mixing conventions with collaborators.State the rule: "37 working days, start date excluded, holidays not yet subtracted."

Frequently Asked Questions

How many working days are in a year?

2026 has 260 working days before holidays (365 calendar days − 105 weekend days). Depending on how the weekends fall, years range from 260 to 262; with ~10–11 public holidays on weekdays, a typical US work year lands near 250.

Is Friday a business day? Is Saturday?

Under the standard definition, business days are Monday through Friday, so Friday counts and Saturday does not. Exceptions exist: some industries (retail, healthcare) treat Saturday as a working day, and some countries have Sunday–Thursday or Friday–Saturday work weeks. The counting method is identical once you define which days to exclude.

Do holidays count as business days?

Under the plain Mon–Fri definition, yes — a Tuesday holiday is still a "business day" unless the governing document says to exclude it. For planning purposes, count Mon–Fri first, then subtract weekday holidays explicitly, as in the November examples above.

How long is 10 business days in calendar days?

Exactly 14 calendar days if the span starts on a Monday and crosses no holidays (two full weeks). Starting on other days of the week the landing date shifts a day or two either way, and holidays push it further. That's why shipping estimates say "business days" — it standardizes for weekends, not holidays.

What's the fastest way to get an exact answer?

Use a calculator that excludes weekends for you. Our date calculator computes days between two dates with an exclude-weekends option, then subtract any holidays inside the range by hand.

Related Calculators

• Date Calculator — Days between dates, weekends excluded on request
• Time Card Calculator — Turn weekly work hours into total pay
• How to Calculate Days Between Dates — The calendar-day companion to this guide
• How to Calculate Work Hours on a Time Card — Hours and minutes within working days