Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 27, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	NOCOPI TECHNOLOGIES INC/MD/
Entity Central Index Key	0000888981
Current Fiscal Year End Date	--12-31
Document Type	10-K
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Public Float			$ 2,325,000
Entity Common Stock Shares Outstanding		58,616,716
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes