Cover Page - shares	6 Months Ended
	Jun. 30, 2026	Jul. 31, 2026
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2026
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q2
Document Transition Report	false
Entity File Number	001-42790
Registrant Name	Heartflow, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-0506743
Entity Address, Address Line One	135 Main Street, Suite 1000
Entity Address, City or Town	San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94105
City Area Code	650
Local Phone Number	241-1221
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	HTFL
Security Exchange Name	NASDAQ
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
Entity Common Stock, Shares Outstanding		86,953,627
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001464521
Amendment Flag	false