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Kalkulačka čísla týdne

Week Number Calculator

Date

What is Week Number Calculator?

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Číslo týdne ISO identifikuje týden v roce, do kterého datum spadá. ISO 8601 definuje týden 1 jako obsahující první čtvrtek v roce, přičemž týdny začínají pondělím. Čísla týdnů se pohybují od 1 do 52 nebo 53.

Calkulon makes complex calculations simple — built for students and everyday problem-solvers.

Vzorec

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f(x)ISO 8601 týden 1: první týden se čtvrtkem v novém roce | 1. týden začíná pondělím | 52–53 týdnů v roce

How to Week Number Calculator

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1Week 1 contains the first Thursday of the year
2Weeks always start on Monday
3Year can have 52 or 53 weeks
4Days in late December may belong to week 1 of the next year

Worked Examples

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Example 1

Given:1 January 2024

Výsledek:Monday; Week 1 of 2024 (2024 starts on a Monday — rare!)

Real-World Applications

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Calculating deadlines and project timelines

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Determining exact ages for legal or medical purposes

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Planning events and scheduling across time zones

Week Number Facts

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Fact	Detail
Week starts	Monday (ISO 8601)
Week 1	Contains first Thursday of year
Total weeks	52 (most years) or 53
Max week 53	Occurs in long years
Jan 1 can be	Week 1 or week 52/53 of prior year

Frequently Asked Questions

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What is Week Number?

ISO week number identifies which week of the year a date falls in. ISO 8601 defines week 1 as containing the first Thursday of the year, with weeks starting on Monday

How accurate is the Week Number calculator?

The calculator uses the standard published formula for week number. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Week Number calculator use?

This calculator works with inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Week Number calculator use?

The calculator applies the standard formula for this type of calculation. See the 'How It Works' steps above for the detailed formula breakdown.

References

›ISO week date — Wikipedia

Formula-verified for precision

Reviewed October 2026

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