Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 10, 2019
Document Information [Abstract]
Entity Registrant Name	Pinterest, Inc.
Entity Central Index Key	0001506293
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		86,250,000
Class B common stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		456,286,871