Claude Opus 5 vs Gemini 3.1 Pro
Both are Flagship-tier models, from Anthropic and Google respectively. Gemini 3.1 Pro is the cheaper choice overall at a 4:1 input:output ratio.
Which is cheaper
- Input price: Gemini 3.1 Pro is cheaper ($2.00 vs $5.00).
- Output price: Gemini 3.1 Pro is cheaper ($12.00 vs $25.00).
- Blended, 4:1 input:output ratio: Gemini 3.1 Pro is 55.6% cheaper ($4.00 vs $9.00 per weighted 1M tokens).
Side by side
| Spec | Claude Opus 5 | Gemini 3.1 Pro |
|---|---|---|
| Provider | Anthropic | |
| Tier | Flagship | Flagship |
| Context window | 1M | 1M |
| Max output | 128K | 66K |
| Input $/1M | $5.00 | $2.00 |
| Output $/1M | $25.00 | $12.00 |
| Cache read $/1M | $0.50 | $0.20 |
| Cache write $/1M | $6.25 | — |
| Modalities | text, image | text, image |
Claude Opus 5. 5-minute cache write shown ($6.25 = 1.25x base input); 1-hour cache write is $10/MTok (2x base). Batch API is 50% off ($2.50/$12.50). Context window and max output cross-checked against platform.claude.com/docs/en/about-claude/models/overview.
Gemini 3.1 Pro. Listed as gemini-3.1-pro-preview. Standard tier for prompts up to 200K tokens; above that, $4 input / $18 output and $0.40 cache read per 1M. Cached context is also billed for storage at $4.50 per 1M tokens per hour.
Sources
Claude Opus 5 — verified August 29, 2026
Gemini 3.1 Pro — verified August 29, 2026
Full Claude Opus 5 pricing page → · Full Gemini 3.1 Pro pricing page →