Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 31, 2021	Jun. 30, 2020
Document Information [Line Items]
Entity Central Index Key	0001307579
Entity Registrant Name	LIQTECH INTERNATIONAL INC
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-36210
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	20-1431677
Entity Address, Address Line One	Industriparken 22C, DK 2750
Entity Address, City or Town	Ballerup
Entity Address, Country	DK
City Area Code	45
Local Phone Number	31315941
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	LIQT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 118,122,891
Entity Common Stock, Shares Outstanding		21,697,373