周数计算器
计算任何日期的 ISO 周数
tools.weekNumberCalculator.title
tools.weekNumberCalculator.description
tools.weekNumberCalculator.isoStandard
Week Number Calculator determines the ISO week number for any date and calculates date ranges for specific weeks in international standards.
Características Principales
ISO week number
Week date range
Year week selection
Multi-year support
Monday start option
Week planning
How to Use Week Number Calculator
Enter Date
Select or input a date
Get Week Number
See the ISO week number
View Week Range
Check the date range for that week
Plan Week
Use for weekly scheduling
Casos de Uso
Project management
Weekly reporting
Scheduling systems
Date standardization
Preguntas Frecuentes
What is the ISO week date system?
ISO 8601 defines week 1 as the first week with a Thursday, ensuring weeks start on Monday.
Why are some years 53 weeks long?
Years with 53 weeks occur roughly every 5-6 years when January 1 falls on a Thursday.
How does this differ from US week numbering?
The US system starts weeks on Sunday and counts differently. ISO is international standard.
Can I convert back from week number to dates?
Yes, enter the week number and we'll show the date range for that week.