Compare
Claude Fable 5 vs Claude Opus 4.8
Input, output, and cached reads all scale by the same multiple between these two, so Claude Opus 4.8 comes out 2.0× cheaper on every shape below — not just some of them. No traffic pattern flips this one.
Per million tokens
Claude Fable 5
Claude Opus 4.8
Monthly cost by workload
Chat assistant
60,000 requests · 1,200 in / 400 out · 30% cached — short prompts, short answers, high volume
Claude Fable 5
$1,726
Claude Opus 4.8
$862.80
Claude Opus 4.8 is 2.0× cheaper on this shape — $862.80 a month.
RAG over documents
20,000 requests · 18,000 in / 700 out · 75% cached — large retrieved context, heavily cached prefix
Claude Fable 5
$1,870
Claude Opus 4.8
$935.00
Claude Opus 4.8 is 2.0× cheaper on this shape — $935.00 a month.
Coding agent
4,000 requests · 45,000 in / 6,000 out · 80% cached — long tool-calling loops, big cached prefix
Claude Fable 5
$1,704
Claude Opus 4.8
$852.00
Claude Opus 4.8 is 2.0× cheaper on this shape — $852.00 a month.