Week numbers 2027: every week and its dates

Pick a week: the tool gives its Monday and Sunday, and whether it contains an Italian holiday. Numbering follows ISO 8601.

Week 1, 2027

Mon 4 January – Sun 10 January

2027 has 52 ISO 8601 weeks.

Monday4 January 2027
Sunday10 January 2027
Holidays that weekEpiphany
Weeks in the year52
How this is calculated

Prepared by Radif Partners · Method · Law 260/1949 and amendments checked on 28 October 2026

Week numbers are used in factories, logistics, shift rotas and company deadlines, and in Italy they follow ISO 8601. There are three rules: the week starts on Monday, week 1 is the one containing the year's first Thursday, and a year has 52 or 53 weeks. In 2027 the first Thursday is 7 January, so week 1 runs from Monday 4 January to Sunday 10 January. The first three days of the year, Friday 1 to Sunday 3 January, belong to week 53 of 2026. 2027 has 52 weeks, and the last one ends on Sunday 2 January 2028. Easter falls in week 12, 4 October in week 40, Christmas Day in week 51. The tool above works out the week number of any date and the days it covers, from Monday to Sunday.

How weeks are counted

ISO 8601 solves a practical problem: a year is not made of whole weeks, so a rule is needed to decide which year the days at the turn belong to. The Thursday rule guarantees that every week has at least four days in the year it is assigned to. Years starting on a Thursday, or on a Wednesday in a leap year, have 53 weeks; 2026 was one of them.

The tool above gives the dates of any week. To see every week at once, with the number next to each row of the month, use the calendar 2027.

Weeks and working days

An ordinary week has five working days, Monday to Friday. In 2027 weeks with a holiday on a weekday have four. The month-by-month count is on working days 2027.

Working days 2027 in Italy

Working days 2027 in Italy

254

Mondays to Fridays in the year261
of which holidays7
First half125
Second half129
Working days in 2027 →

The holidays that shorten a week are those of Law 260 of 1949 as amended, including since 2026 the 4 October holiday of Law 151 of 2025.

Common questions

Why is 1 January 2027 in week 53?

Because an ISO week belongs to the year its Thursday falls in. The week from 28 December 2026 to 3 January 2027 has its Thursday on 31 December 2026, so it is week 53 of 2026. The first week of 2027 starts on Monday 4 January.

Which weeks of 2027 contain an Italian holiday?

Seven weeks have a holiday on a weekday: those of Epiphany, Easter Monday, 2 June, 4 October, All Saints' Day, the Immaculate Conception and the New Year week, which belongs to 2026. The tool lists the holidays of any week you choose.

Does the US calendar number weeks the same way?

No. In the United States the week starts on Sunday and week 1 is the one containing 1 January. So an American and an Italian diary can be a week apart at the start of the year. Italy and the rest of Europe use ISO 8601.

Keep going

Calendar 2027

Printable, with holidays and week numbers

Working days 2027

Month by month, five or six-day week, with the patron saint

Public holidays 2027

Italy’s 2027 public holidays with the weekday

Official sources for this page

Prepared by

Publisher of an independent calendar that works out Italy's national holidays, patron saints' days and long weekends

Updated on · Editorial policy · Contact

As of 2026, Law 260/1949 and its amendments checked on