Condensed Consolidated Statements of Operations and Comprehensive Income/(Loss) (Unaudited) - USD ($)	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues	$ 43,130,934	$ 43,518,384
Cost of revenues	26,162,582	25,897,181
Gross profit	16,968,352	17,621,203
Operating expenses
General and administrative	22,538,496	20,363,728
Research and development	3,171,676	1,827,286
Total operating expenses	25,710,172	22,191,014
Operating income/(loss)	(8,741,820)	(4,569,811)
Other income/(expense)
Other income/(expense)	8,758,212	1,821,029
Settlement Agreement - Related Party	3,674,165
Interest Expense	(2,921,345)	(4,607,453)
Total other income/(expense), net	9,511,032	(2,786,424)
Net loss before income taxes	769,212	(7,356,235)
Income tax benefit/(expense)	(375,434)	(2,073,835)
Income/Loss from Continuing operations	393,778	(9,430,070)
Loss from discontinued operations, net of tax	(8,280,047)	(812,895)
Net income/(loss)	(7,886,269)	(10,242,965)
Less income/(loss) in noncontrolling interest	(78,274)	227,116
Net income/(loss) attributable to Cemtrex, Inc. shareholders	(7,807,995)	(10,470,081)
Net income/(loss)	(7,886,269)	(10,242,965)
Other comprehensive income/(loss)
Foreign currency translation gain/(loss)	996,100	57,639
Defined benefit plan actuarial gain/(loss)	87,895
Comprehensive income/(loss)	(6,802,274)	(10,185,326)
Less comprehensive income/(loss) attributable to noncontrolling interest	78,274	(227,116)
Comprehensive income/(loss) attributable to Cemtrex, Inc. shareholders	$ (6,880,548)	$ (9,958,210)
Income/(loss) Per Share-Basic
Income/(loss) Per Share-Basic- Continuing operations	$ 0.02	$ (1.00)
Income/(loss) Per Share-Basic - Discontinued operations	(0.44)	(0.08)
Income/(loss) Per Share-Diluted- Continuing operations
Income/(loss) Per Share-Diluted	0.02	(1.00)
Income/(loss) Per Share-Diluted - Discontinued operations	$ (0.44)	$ (0.08)
Weighted Average Number of Shares-Basic	18,911,746	9,611,516
Weighted Average Number of Shares-Diluted	18,911,746	9,611,516

Settlement agreement related party.

No definition available.

Name:	CETX_SettlementAgreementRelatedParty
Namespace Prefix:	CETX_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(22))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(24))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e557-108580

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(26))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669625-108580

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669619-108580