Excel WEEKNUM Function
Chala mitrano — today WEEKNUM. Turn a date into a week number for planning boards and ISO reports.
चला मित्रांनो — आज WEEKNUM. तारीख week number मध्ये बदला — planning आणि ISO reports साठी.
चलो दोस्तों — आज WEEKNUM. तारीख को week number बनाओ — planning और ISO reports के लिए.
Purpose
Return the week number of the year for a date.
Return value
A week number.
Syntax
Arguments
| Argument | Required? | Description |
|---|---|---|
serial_number | Required | A date. |
return_type | Optional | 1 = week begins Sunday; 2 = Monday; 21 = ISO week system. |
Version
All modern Excel; LibreOffice WEEKNUM. For strict ISO weeks prefer ISOWEEKNUM when available.
How to use — Why → What → How
Why: Warehouses talk in week numbers (‘ship in W44’). WEEKNUM prints that number from any date. Logistics hubs in Nagpur and Hamburg plan by week number. In Indian back offices and foreign sister teams, WEEKNUM shows up on leave, SLA and invoice sheets every week.
What: WEEKNUM returns the week of year. return_type picks Sunday-start, Monday-start, or ISO (21). Read every argument in the table once before you type; each one changes the answer on purpose.
How — numbered steps:
- Type =WEEKNUM(A2,21) for ISO.
- Agree the system with your team.
- Pair with YEAR for unique week keys.
Ravindra Bagale's Tip
Friends, after you learn WEEKNUM, open a real schedule sheet and find one cell this function would fix this week.
Ravindra Bagale's Tip – मराठी
मित्रांनो, WEEKNUM शिकून झाल्यावर खरी schedule sheet उघडा.
Ravindra Bagale's Tip – हिंदी
दोस्तों, WEEKNUM सीखने के बाद असली schedule sheet खोलो.
Ravindra Bagale's Tip
Friends, sleep on WEEKNUM and rebuild example 1 tomorrow without looking.
Ravindra Bagale's Tip – मराठी
मित्रांनो, WEEKNUM वर एक रात्र झोपा आणि उद्या उदाहरण 1 न पाहता पुन्हा लिहा.
Ravindra Bagale's Tip – हिंदी
दोस्तों, WEEKNUM पर एक रात सोकर कल उदाहरण 1 बिना देखे फिर लिखो.
Ravindra Bagale's Tip
Friends, say the business question in plain words before =WEEKNUM.
Ravindra Bagale's Tip – मराठी
मित्रांनो, =WEEKNUM आधी प्रश्न साध्या शब्दांत सांगा.
Ravindra Bagale's Tip – हिंदी
दोस्तों, =WEEKNUM से पहले सवाल सादे शब्दों में बोलो.
Ravindra Bagale's Tip
Friends, after you finish WEEKNUM, open yesterday’s real workbook and find one place this function would have saved ten minutes. That habit turns lessons into salary skills.
Ravindra Bagale's Tip – मराठी
मित्रांनो, WEEKNUM शिकून झाल्यावर कालची खरी वर्कबुक उघडा आणि शोधा जिथे हे फंक्शन दहा मिनिटे वाचवू शकले असते.
Ravindra Bagale's Tip – हिंदी
दोस्तों, WEEKNUM सीखने के बाद कल की असली वर्कबुक खोलो और ढूँढो जहाँ यह फ़ंक्शन दस मिनट बचा सकता था.
Ravindra Bagale's Tip
Friends, treat WEEKNUM like a seatbelt on date sheets — use it before a manager asks why the deadline slipped.
Ravindra Bagale's Tip – मराठी
मित्रांनो, WEEKNUM ला date sheets वरील seatbelt समजा — manager विचारण्यापूर्वी वापरा.
Ravindra Bagale's Tip – हिंदी
दोस्तों, WEEKNUM को date sheets पर seatbelt समझो — manager पूछे उससे पहले इस्तेमाल करो.
Download practice file: practice-weeknum.xlsx (includes sheet About this data, practice sheets, and Answers).
Worked examples
1) Default week
Nagpur dispatch.
| Date | ₹ |
|---|---|
| 2026-10-31 | 15000 |
Result: 44
What it means: ISO week number (return_type 21) for 31 Oct 2026.
2) ISO week
Hamburg €.
| Date | € |
|---|---|
| 2026-10-31 | 820 |
Result: 44
What it means: ISO week for 31 Oct 2026.
3) Monday system
Type 2.
| Date |
|---|
| 2026-01-01 |
Result: 1
What it means: Monday-start numbering.
4) Year+week key
Unique key.
| Date |
|---|
| 2026-10-31 |
Result: 2026-W44
What it means: Stable label for pivots.
5) Compare systems
Same date.
| Date |
|---|
| 2026-01-04 |
Result: (system1 / ISO)
What it means: Systems can disagree near year starts.
6) Filter one week
Keep ISO 44.
| Date |
|---|
| 2026-10-28 |
| 2026-11-05 |
Result: W44 on first row
What it means: Flag matching week.
Common errors and fixes
Notes and tips
- Revisit WEEKNUM errors after quiz.
- Build one example from memory.
- Check formats if wrong.
- Teach a tip in Marathi/Hindi.
- Keep currency consistent in one column.
- Note version fallbacks.
- Drill: tag five dates with week numbers for a dispatch board.
- WEEKNUM vs ISOWEEKNUM: WEEKNUM has systems; ISOWEEKNUM is always ISO weeks.
- Fictional data only.
- Print WEEKNUM revision card.
- Predict before Enter.
- Track top mistake monthly.
- Logistics hubs in Nagpur and Hamburg plan by week number.
- Dates are serials.
- Verify on a known calendar.
- Print the revision card for WEEKNUM and stick it near your monitor for one week of real worksheets.
- When helping a junior, ask them to predict the result before pressing Enter — prediction builds judgement.
- Keep a personal notebook of the one mistake you make most often with this function; review it monthly.
- Share one tip from this page with a classmate in Marathi or Hindi — teaching locks the idea.
- If a result looks wrong, check date formats and regional settings before changing the formula.
- Date serial numbers are how Excel stores dates — formatting only changes the display.
- Share one tip from this page with a classmate in Marathi or Hindi — teaching locks the idea.
- Keep currency symbols consistent inside a single report column even when practice mixes ₹ $ £ € across examples.
- Classroom habit: after WEEKNUM, open yesterday’s real workbook and find one place this function saves time.
- For interviews, explain why calendar days and working days differ on a project that crosses a weekend.
In real work
Drill: tag five dates with week numbers for a dispatch board. Logistics hubs in Nagpur and Hamburg plan by week number. Classroom drill: write three brand-new WEEKNUM formulas on a blank sheet using names from your own city — if you can invent them without the page open, you own the skill. Then break one formula on purpose and watch the error; recovering from that break is half of interview readiness. Always verify with a known calendar date before trusting a long chain of date formulas. Keep a personal notebook of the one mistake you make most often with this function; review it monthly. When Excel versions differ at home and in class, write the fallback formula under the modern one in a comment cell.
How it compares
WEEKNUM vs ISOWEEKNUM: WEEKNUM has systems; ISOWEEKNUM is always ISO.
Interview corner
- ISO?
- return_type 21.
- Why disagree near Jan?
- Different week rules.
- Key with year?
- Concatenate YEAR and week.
Related functions
Practice tasks (10)
- Task 1. WEEKNUM of 31-Oct-2026 default.Default.
- Task 2. ISO week same date.21.
- Task 3. Build YEAR-Wxx key.Join.
- Task 4. Flag ISO 44.IF.
- Task 5. Compare systems on 4 Jan 2026.Both.
- Task 6. Document chosen system.Note.
- Task 7. Explain ISO to classmate.Teach.
- Task 8. Fill week column.Fill.
- Task 9. Interview: why systems differ.Talk.
- Task 10. Bonus: ISOWEEKNUM if available.Related.
Quick quiz
Answers: Q1=21, Q2=Week number, Q3=Systems disagree, Q4=YEAR & WEEKNUM, Q5=ISO (21) (check after you try).
Revision card
Standalone card (no tip or photo strip). QR opens this lesson. Download the PNG and revise offline.
