Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 03, 2018	Jun. 30, 2017
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, 2017
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	Accelerated Filer
Entity Common Stock, Shares Outstanding		3,374,061
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2017
Entity Public Float			$ 84,519,435