Side-by-side technical and economic comparison between Anthropic's Claude Opus 5 and Google's Gemini 3.8 Flash.
| Metric | Claude Opus 5 | Gemini 3.8 Flash | Advantage |
|---|---|---|---|
| Provider Organization | Anthropic | — | |
| Standard Input / 1M | $5.00 | $0.75 | Gemini 3.8 Flash (85% lower) |
| Cached Input / 1M | $0.50 | $0.075 | Gemini 3.8 Flash lower |
| Output / 1M | $25.00 | $3.75 | Gemini 3.8 Flash lower |
| Context Window | 1M | 1.05M | Gemini 3.8 Flash (1.05M) |
| Max Generation Tokens | 16.4k | 16.4k | Claude Opus 5 |
| Tokenizer Family | Anthropic Claude BPE (~65k vocabulary) | Google Gemini SentencePiece (256k vocabulary) | — |
Opt for Claude Opus 5 when your engineering requirements prioritize Anthropic's ecosystem, specific tokenizer efficiencies (Calibrated Claude Tokenizer (±3%)), or when your expected prompt-to-completion ratios favor its $5/M input rate.
Opt for Gemini 3.8 Flash when looking for Google's tooling integration, specific context window depth (1.05M tokens), or when output generation volume favors its $3.75/M rate.