Document and Entity Information - shares	9 Months Ended
	Sep. 28, 2024	Oct. 22, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 28, 2024
Document Transition Report	false
Entity File Number	001-33264
Entity Registrant Name	CARPARTS.COM, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	68-0623433
Entity Address, Address Line One	2050 W. 190th Street
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	Torrance
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90504
City Area Code	424
Local Phone Number	702-1455
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	PRTS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Smaller Reporting Company	false
Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		57,399,643
Entity Central Index Key	0001378950
Current Fiscal Year End Date	--12-28
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false