Weeks Calendar 2027
Explore every ISO week in 2027 with exact Monday-to-Sunday date ranges. This year has 52 ISO weeks, starts on Friday, January 1, and ends on Friday, December 31.
Popular Calculators
Weeks Between Dates
Calculate the number of full weeks and remaining days between two selected dates.
Open Weeks Calculator →Business Days
Count weekdays between dates for deadlines, delivery estimates and work schedules.
Open Business Tool →Date to Week Number
Convert any date into its ISO week number and ISO week-year for reports or planning.
Open Week Number Tool →More Planning Tools
Deadline Calculator
Add days, weeks or business days to a start date and estimate the final deadline.
Open Tool →Project Timeline
Estimate a finish date from a start date, planned weeks and optional buffer time.
Open Tool →Payroll Period
Estimate weekly and biweekly payroll periods for operations and timesheet planning.
Open Tool →Frequently Asked Questions
Is 2027 the current ISO year?
No. This page is focused on the ISO week calendar for 2027, so it shows year-specific week ranges instead of today’s current-week status.
How many weeks are in 2027?
2027 has 52 ISO weeks.
Why do some years have 53 weeks?
An ISO year has 53 weeks when the weekday alignment creates an extra complete Monday-to-Sunday week.
Useful Week Guides
What Week Is It Today?
Find the current ISO week number and see how week numbers help with planning.
Week Number Today
See today’s ISO week number and how it applies to schedules, reports, and planning.
ISO Week Number Explained
A clear explanation of ISO weeks, week-years, and the rule that defines week 1.
Week Number to Date: How to Find ISO Week Dates
Convert an ISO week number into its Monday-to-Sunday calendar date range.
How Many Weeks Are in a Year?
Understand why most years have 52 ISO weeks and some have 53.
Which Years Have 53 ISO Weeks?
Check why some ISO years contain week 53 and which upcoming years have an extra reporting week.