Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2021	Aug. 01, 2021
Document Information [Line Items]
Entity Registrant Name	BION ENVIRONMENTAL TECHNOLOGIES INC
Entity Central Index Key	0000875729
Trading Symbol	bnet
Current Fiscal Year End Date	--06-30
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		40,727,677
Entity Public Float	$ 41.5
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Title of 12(g) Security	Common Stock, No Par Value