Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2012	Mar. 02, 2013	Jun. 30, 2012
Document And Entity Information
Entity Registrant Name	ACME UNITED CORP
Entity Central Index Key	0000002098
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Is Entity a Well-known Seasoned Issuer?	No
Is Entity a Voluntary Filer?	No
Is Entity's Reporting Status Current?	Yes
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		3,142,202
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2012
Entity Public Float			$ 26,794,065