CalculationTime

ISO Week Calendar

A printable week-date tool for ISO week numbers, Monday-start planning, 52 or 53 week-years, and date conversion beside the CalculationTime clockface.

Time Duration Calculator

Week Builder

Build a printable ISO week

CalculationTime ISO Week Calendar

2026-W30

Monday 20 July 2026 to Sunday 26 July 2026
Week-Year
2026
Weeks In Year
53
Business Days
5
Boundary
Clear
Selected dateSunday 26 July 2026
ISO week date2026-W30-7
ISO weekdaySunday
Mon20

20 July 2026

ISO Day
1
Year Day
201
Tue21

21 July 2026

ISO Day
2
Year Day
202
Wed22

22 July 2026

ISO Day
3
Year Day
203
Thu23

23 July 2026

ISO Day
4
Year Day
204
Fri24

24 July 2026

ISO Day
5
Year Day
205
Sat25

25 July 2026

ISO Day
6
Year Day
206
Sun26

26 July 2026

ISO Day
7
Year Day
207

Week-Year Window

ISO 2026 starts Monday 2025-12-29 and the next ISO week-year starts Monday 2027-01-04.

Notes

Sprint goals, release windows, roster notes, deadlines and review checkpoints.

Assumptions

ISO 8601 Monday-start weeks, local browser Gregorian dates, selected sheet range 2026-07-20 to 2026-07-26.

Method

ISO weeks are built from the Thursday rule

ISO week 1 is the week containing the year's first Thursday. The calculator finds the Monday of week 1 from January 4, then adds whole weeks to build the selected Monday to Sunday sheet. Date conversion uses the same Thursday anchor so early January and late December dates can belong to the neighbouring ISO week-year.

Week-year range

The planner accepts ISO week-years from 1900 through 2100 and automatically limits the week number to 52 or 53.

Print path

The print button opens browser print and the print stylesheet keeps the week sheet, converted date result, notes and assumptions.

Limits

This page does not infer public holidays, fiscal calendars, payroll periods or regional work rules. It only calculates ISO week-date structure.

Source Notes

Standards and platform basis

The page labels week numbers using the ISO 8601 week-date convention: weeks start on Monday, and week 1 is the week containing the first Thursday of the Gregorian year. Browser JavaScript Date objects provide the underlying Gregorian date arithmetic.

ReferencesISO 8601 date and time formatECMAScript Date objects