Cover - shares	3 Months Ended
	Mar. 31, 2022	May 05, 2022
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-40276
Entity Registrant Name	Semrush Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-4053265
Entity Address, Address Line One	800 Boylston Street, Suite 2475
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02199
City Area Code	(800)
Local Phone Number	851-9959
Title of 12(b) Security	Class A Common Stock, $0.00001 par value per share
Trading Symbol	SEMR
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001831840
Current Fiscal Year End Date	--12-31
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		43,119,803
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		97,975,754