Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2020	Nov. 18, 2020	Mar. 27, 2020
Cover [Abstract]
Entity Registrant Name	PTC Inc.
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2020
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	04-2866152
Title of 12(b) Security	Common Stock, $.01 par value per share
Trading Symbol	PTC
Security Exchange Name	NASDAQ
Entity File Number	0-18059
Amendment Flag	false
Entity Central Index Key	0000857005
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Address, Address Line One	121 Seaport Boulevard
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	781
Local Phone Number	370-5000
Entity Public Float			$ 6,144,651,405
Entity Common Stock, Shares Outstanding		116,662,768
Entity Emerging Growth Company	false
Documents Incorporated by Reference	Portions of the definitive Proxy Statement in connection with the 2021 Annual Meeting of Stockholders (2021 Proxy Statement) are incorporated by reference into Part III.