Business Days Calculator

A business day — a working day, a weekday in the loose sense — is a day on which normal commerce happens. Two things take a day out of the count, and they are independent of each other: the day of the week, and the holiday calendar you are working to.

Four steps, and the third is the one that separates a right answer from a nearly-right one.

1. 1

   Count the calendar days, endpoints included

   Subtract the earlier date from the later one and add one, because both the first and the last day of the period are days of the period. Do this on plain calendar dates, not on timestamps — a clock-based subtraction can drop or gain a day across a daylight-saving change.

   2026-07-19 − 2026-07-06 + 1 = 14 days
2. 2

   Take out the whole weeks, then the ragged ends

   Divide by seven to get the whole weeks; each contributes exactly two weekend days. Then walk the leftover days one at a time from the start weekday and count how many of those are weekend days too. This is the part a naive five-sevenths estimate gets wrong.

   2 weeks × 2 = 4 weekend days → 10 weekdays
3. 3

   Remove holidays on their observed dates, not their statutory ones

   Look up each public holiday in the range. If it already falls at the weekend it has been shifted — Saturday holidays back to the Friday, Sunday holidays forward to the Monday — so remove the observed date. Never remove a holiday twice, and never remove one that fell on a day you were not working anyway.

   23 weekdays − 1 observed = 22 working days in July 2026
4. 4

   For a deadline, step forward instead of subtracting

   Counting to a date is a different operation from counting between dates. Start on the day after the trigger event and advance one calendar day at a time, ticking off a business day whenever the day is a working one, until the tally is reached. The start date is never counted.

   2026-11-20 + 10 business days → 2026-12-07

Almost every “your calculator is wrong” complaint about working days is really a disagreement about whether the endpoints count. There is no universally correct convention, only the correct one for the question — so here is exactly what each mode of this calculator does, in words.

The two counts always differ by exactly one. If a figure here disagrees with another tool, check this before anything else — it is the explanation nine times out of ten.

One example per situation, with the intermediate arithmetic left in. Switch tabs to see how the working changes when a holiday, a month boundary, or a six-day week is involved.

The holiday set built into this calculator is the eleven federal holidays of 5 U.S.C. § 6103, current as of 2026 and including Juneteenth, which was added in June 2021. Four are fixed dates; the other seven are weekday rules that have to be generated per year rather than looked up, which is exactly where hand-built holiday lists go wrong.

Observed dates, 2026 to 2028

The dates federal offices actually close. The calculator itself is not limited to these years — it generates the rules for any year you give it — but this is the range printed on the page for reference.

Accent-coloured cells are shifted observances. Rule set current as of 2026; a New Year’s Day falling on a Saturday is observed on December 31 of the previous year, so holiday tables must always be generated a year either side of the range they cover.

The counts people look up most often: how many working days are in a given month or year, and what date falls a given number of business days from today. Every figure is generated from the same holiday rules the calculator uses.

The single biggest source of a wrong business-day count is removing a day that the statute never removed. Each of these closes a lot of doors without being a federal holiday, so a deadline written in federal business days keeps running straight through them. If your own office closes, add the dates in the extra days off field on the calculator.

“Business day” is not one calendar, it is several, and they differ in ways that matter when money has to settle. Two correct calculators can give different answers simply because they model different institutions — so it is worth knowing which one your deadline was written against.

Working-day arithmetic is invisible until it is wrong, and then it is expensive. These are the places it matters most.

The five-day week is a convention, not a constant. The calculator lets you switch any day on or off, because a contract that says “working days” without defining them takes its meaning from the week the parties actually keep.

Six things that decide whether two people counting the same period agree on the number.

If the question is broader or narrower than working days, one of these fits better than the tool above.

Sample check: 2026-07-06 to 2026-07-19 is 14 calendar days and 10 working days; 2026 holds 250 working days in total.

Common questions