Document And Entity Information - USD ($)	12 Months Ended
	May 31, 2021	Aug. 27, 2021	Nov. 30, 2020
Document Information Line Items
Entity Registrant Name	BIOMERICA INC
Document Type	10-K/A
Current Fiscal Year End Date	--05-31
Entity Common Stock, Shares Outstanding		12,510,210
Entity Public Float			$ 66,938,974
Amendment Flag	true
Amendment Description	As disclosed in our Current Report on Form 8-K filed on September 30, 2021, subsequent to the issuance of the Original Form 10-K, we determined that our calculation and expense of non-cash stock-based compensation, related to issued stock options, as reported in our consolidated financial statements, have been materially understated based on the application of accounting principles generally accepted in the United States. We are filing this Amendment No. 1 on Form 10-K/A to reflect restatements to our consolidated financial statements for the years ended May 31, 2021 and 2020 to correct such errors in our accounting for non-cash stock based compensation
Entity Central Index Key	0000073290
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	May 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes