v3.25.2
FT Vest U.S. Equity Dual Directional Buffer ETF - November N-1A Cover
Sep. 17, 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 Sep. 17, 2025
Prospectus Date Sep. 18, 2025