v3.26.1
Cover
Jun. 05, 2026
Entity Addresses [Line Items]  
Document Type 8-K
Amendment Flag false
Document Period End Date Jun. 05, 2026
Entity File Number 001-42629
Entity Registrant Name FACTORIAL ENERGY INC.
Entity Central Index Key 0002049662
Entity Tax Identification Number 42-2967285
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 805 Middlesex Turnpike
Entity Address, City or Town Billerica
Entity Address, State or Province MA
Entity Address, Postal Zip Code 01821
City Area Code 617
Local Phone Number 315-9733
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Elected Not To Use the Extended Transition Period false
Series A Common Stock, par value $0.00001 per share  
Entity Addresses [Line Items]  
Title of 12(b) Security Series A Common Stock, par value $0.00001 per share
Trading Symbol FAC
Security Exchange Name NASDAQ
Warrants, each whole warrant exercisable for one share of Series A Common Stock at an exercise price of $11.50  
Entity Addresses [Line Items]  
Title of 12(b) Security Warrants, each whole warrant exercisable for one share of Series A Common Stock at an exercise price of $11.50
Trading Symbol FACWW
Security Exchange Name NASDAQ
Former Address [Member]  
Entity Addresses [Line Items]  
Entity Address, Address Line One CARTESIAN GROWTH CORPORATION III
Entity Address, Address Line Two 505 Fifth Avenue
Entity Address, Address Line Three 15th Floor
Entity Address, City or Town New York
Entity Address, State or Province NY
Entity Address, Postal Zip Code 10017