v3.26.1
Form N-1A Cover
Aug. 31, 2025
Prospectus [Line Items]  
Document Type 485BPOS
Amendment Flag false
Registrant Name First Trust Exchange-Traded Fund VIII
Entity Central Index Key 0001667919
Entity Investment Company Type N-1A
Document Period End Date Aug. 31, 2025
Prospectus Date Jun. 05, 2026