Negative effect on net profit loss.

No definition available.

Name:	birk_NegativeEffectOnNetProfitLoss
Namespace Prefix:	birk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of Customers

+ References

No definition available.

+ Details

Name:	birk_NumberOfCustomers
Namespace Prefix:	birk_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of concentration of receivables

+ References

No definition available.

+ Details

Name:	birk_PercentageOfConcentrationOfReceivables
Namespace Prefix:	birk_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of currency weakening against major currency.

+ References

No definition available.

+ Details

Name:	birk_PercentageOfCurrencyWeakeningAgainstMajorCurrency
Namespace Prefix:	birk_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of outstanding funds that the entity is obligated to repay.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_55&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_Borrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maturity of borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2024-01-01
-Paragraph 7
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2024-en-r&anchor=para_7&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_BorrowingsMaturity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfFinancialInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The nominal or face amount of a financial instrument, used to calculate payments made on that instrument.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_NotionalAmount
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

A component of equity representing the accumulated portion of gain (loss) on a hedging instrument that is determined to be an effective hedge for cash flow hedges. [Refer: Cash flow hedges [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 9
-IssueDate 2024-01-01
-Paragraph 6.5.11
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2024-en-r&anchor=para_6.5.11&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_ReserveOfCashFlowHedges
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ifrs-full_ConcentrationsOfRiskAxis=birk_AccountsReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_TypesOfRisksAxis=ifrs-full_InterestRateRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=birk_EuroDenominatedFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=birk_UsdDenominatedFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=birk_NewEuroDenominatedFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=birk_NewUSDDenominatedFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=birk_SeniorTermFacilitiesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financial Risk Management Objectives and Policies - Additional Information (Details) € in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2024 EUR (€) Customer	Sep. 30, 2023 EUR (€)	Sep. 30, 2024 USD ($) Customer
Disclosure of detailed information about financial instruments [line items]
Number of customer \| Customer	1		1
Percentage of concentration of receivables	10.00%		10.00%
Weakening of Euro against major currency	10.00%
Reclassified the cash flow hedge reserve of a cumulative loss	€ 0.3
Negative effect on net profit (loss)	€ 7.1	€ 11.6
Accounts Receivables
Disclosure of detailed information about financial instruments [line items]
Percentage of concentration of receivables	13.00%		13.00%
Interest Rate Risk \| Euro Denominated Facility
Disclosure of detailed information about financial instruments [line items]
Notional amount	€ 375.0
Interest Rate Risk \| USD Denominated Facility
Disclosure of detailed information about financial instruments [line items]
Notional amount \| $			$ 850.0
Interest Rate Risk \| New Euro Denominated Facility
Disclosure of detailed information about financial instruments [line items]
Borrowings	€ 375.0
Interest Rate Risk \| New USD Denominated Facility
Disclosure of detailed information about financial instruments [line items]
Borrowings \| $			$ 280.0
Interest Rate Risk \| Senior Term Facilities Agreement
Disclosure of detailed information about financial instruments [line items]
Maturity date	April 30, 2028, but was extinguished and replaced by the term loans under the new Term and Revolving Facilities Agreement (as defined below) effective August 2, 2024