Working Days Calculator

Weekdays, counted inclusive

Delivery promises, notice periods, project plans and legal deadlines all run on working days, and calendars are full of traps for counting them by hand: months that straddle weekends, holidays inside the window, endpoints that are themselves Saturdays. This page counts Monday to Friday between two dates, both endpoints included when they are themselves weekdays. It deliberately does not subtract public holidays, because those are national or regional facts the tool cannot know; what it guarantees is the five-day-week scaffolding every calendar counts on.

Inclusive counting is the convention to understand before anything else: from Tuesday the 6th to Thursday the 8th is 3 working days, because the Wednesday counts and so do both endpoints. A full Monday to Friday week is 5, a fortnight is 10, and the tool reports the calendar days and weekend days behind the answer so you can audit it.

A worked example, step by step

Problem: a subcontractor starts Monday 5 January 2026 and hands over Friday 30 January 2026. How many working days does the contract calendar show, and how much of January is that?

1. Calendar span: 5 January to 30 January inclusive is 26 days.
2. Weekend days inside: Saturdays 10, 17, 24 and Sundays 11, 18, 25 — six days.
3. Working days: 26 − 6 = 20.
4. Whole-month view: January 2026 starts on a Thursday, has 31 days, and contains 5 Saturdays and 4 Sundays → 22 working days.
5. Q1 all in: 22 + 20 + 22 = 64 working days across January, February and March.

Both answers are useful independently: 20 is what the subcontractor's job tracker should accrue, 22 is what a monthly payroll calendar would bill, and the 2-day gap is exactly the start-and-end half-weeks the month view absorbs.

2026's working-day calendar

261 is the number worth memorising because it anchors so many estimates: a 15-working-day SLA is roughly three real weeks only when no holidays fall inside. After your country's fixed-date holidays (which cluster in spring and December), the true available figure for many offices is 250–255 — and that small subtraction changes delivery promises materially.

Notice periods, SLAs and payment terms

Three real clauses use this count. A 10-working-day notice period from a Friday means the notice ends on the Friday two weeks later, not the calendar Friday after 10 days (which is a Tuesday). A 5-working-day payment term from an invoice dated on the 28th can straddle two months. A 15-working-day delivery promise made on a Thursday before a holiday Monday is a different promise than the same words on a normal Monday. Each clause reads differently to each party; the inclusive convention plus your local holidays is what makes them end in the same meeting room.

Mistakes that quietly break a working-day promise

• Skipping holiday subtraction. The tool counts five-day weeks only; subtract your own list of holidays before promising.
• Assuming "business days" excludes only weekends. Regional holidays, factory shutdowns and industry-specific calendar quirks are on you.
• Starting from the day after and counting inclusive anyway. Doubling up the start boundary adds a day to every estimate.
• Saying "two weeks" when the clause says 10 working days. They are usually 12 calendar days, and the difference lands on the receiver.
• Forgetting the endpoint. The promise from Friday to Friday spans two working-day weeks, 11 days inclusive when the start itself is a weekday.

Keep exploring

• Days Until a Date — the same span read as a pure countdown, with weeks and days split out.
• Date Difference — total date difference without the working-day filter.
• Add Days to a Date — step in the other direction: from a date plus a count, get the end date.
• Guide: Working with Dates and Time.