Business Days Calculator: Holidays and Project Deadlines

Project end date in working days, excluding weekends and holidays

The tool counts working days from the start date, skipping Saturdays, Sundays and the 11 French national public holidays. The effort is first increased by the safety margin, then divided by the number of full-time people: 25 days with a 10% margin make 28 working days, so a project starting on Monday 2 November 2026 ends on Thursday 10 December.

Calculation

• Working days to schedule = (work days × (1 + margin)) ÷ FTE, rounded up.
• The start day counts if it is a working day; the tool then moves forward day by day, skipping weekends and public holidays.
• Holidays are computed for every year the project spans: 1 January, Easter Monday, 1 May, 8 May, Ascension Day, Whit Monday, 14 July, 15 August, 1 November, 11 November, 25 December. Easter is found with the Meeus algorithm and the movable holidays follow from it (+1, +39 and +50 days).
• The whole calculation uses your device's local date.

Examples

Start on Monday 2 November 2026, 25 work days, 10% margin, 1 FTE: 28 working days, ending on Thursday 10 December 2026, i.e. 39 calendar days; Wednesday 11 November is skipped. With 2 FTE, 27.5 ÷ 2 rounded up gives 14 working days and an end on Friday 20 November.

In spring, holidays pile up: the same project starting on Monday 27 April 2026 skips 1 May, 8 May, Ascension Day (Thursday 14 May) and Whit Monday (25 May), and ends on Tuesday 9 June, i.e. 44 calendar days.

Limits

• Only French national holidays are removed: not Good Friday and 26 December in Alsace-Moselle, not the overseas abolition-of-slavery days, not bridge days or leave.
• Whit Monday is treated as a day off, although many French employers use it as the unpaid solidarity day.
• Dividing by FTE assumes the work splits between people with no loss.

This tool sets the schedule; the EVM and profitability calculators track cost and margin.

Sources and dates: the 11 statutory holidays in the French Labour Code (Articles L3133-1 et seq.); 2026 dates from Service-Public.fr, page checked on 1 January 2026 (Easter Monday 6 April, Ascension 14 May, Whit Monday 25 May) (checked 14/10/2026).

Frequently Asked Questions

How many public holidays are there in France?

The French Labour Code lists 11: 1 January, Easter Monday, 1 May, 8 May, Ascension Day, Whit Monday, 14 July, 15 August, 1 November, 11 November and 25 December. Alsace-Moselle adds Good Friday and 26 December, and each overseas department adds its abolition-of-slavery day.

How do I calculate an end date in working days?

Start from the start date and count only Monday-to-Friday days that are not public holidays. 28 working days from Monday 2 November 2026 lead to Thursday 10 December, because 11 November is skipped.

What safety margin should a schedule include?

No standard sets it; the tool suggests 10% by default, applied before rounding. 25 work days thus become 27.5, then 28 working days, 3 days more than the raw estimate.

Does adding a person halve the duration?

In the tool, yes: the effort is divided by the number of FTE, so 28 working days become 14 with 2 people. In practice, tasks that depend on each other and coordination time reduce that gain, so keep the safety margin.

Are next year's public holidays taken into account?

Yes: the tool loads the holidays of every year the project spans. A 10-working-day project starting on Monday 21 December 2026 skips 25 December and 1 January and ends on Tuesday 5 January 2027.

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.