Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document And Entity Information
Entity Registrant Name	ACME UNITED CORP
Entity Central Index Key	0000002098
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Is Entity's Reporting Status Current?	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		3,352,130
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2019
Entity Emerging Growth Company?	false
Entity Small Business?	true