Claude Opus 5.5 vs Gemini 3.1 Pro
Claude Opus 5.5 costs $4.00 / $20.00 and Gemini 3.1 Pro costs $2.00 / $12.00 per million input / output tokens. At a typical 3:1 mix, Gemini 3.1 Pro is 1.8× cheaper than Claude Opus 5.5.
Claude Opus 5.5
Anthropic
Input
$4.00
per 1M
Output
$20.00
per 1M
Cached
$0.20
1M context
Input
$2.00
per 1M
Output
$12.00
per 1M
Cached
$0.20
1M context
Side by side
Green marks the cheaper price, larger context window, bigger discount or higher score.
| Detail | Claude Opus 5.5 | Gemini 3.1 Pro |
|---|---|---|
| Input per 1M | $4.00 | $2.00 |
| Output per 1M | $20.00 | $12.00 |
| Blended per 1M (3:1) | $8.00 | $4.50 |
| Cached input per 1M | $0.20 | $0.20 |
| Batch or off-peak discount | 50% (batch) | 50% (batch) |
| Long prompts | Same rate at any length | Over 200K: $4 / $18 |
| Context window | 1M | 1M |
| Released | 22 Sep 2026 | Feb 2026 |
| Open weights | No | No |
| Arena text score | 1509 | 1487 |
| Verified | 27 Sep 2026 | 27 Sep 2026 |
Sources: Anthropic pricing and Gemini API pricing.
Monthly cost on three workloads
List prices, no batch discount. The cached share applies where a model has a cache rate.
| Workload | Claude Opus 5.5 | Gemini 3.1 Pro | Difference |
|---|---|---|---|
| Customer chat assistant50,000 conversations a month, about 2,000 tokens in and 400 out each; 50% cached | $610 | $350 | $260 |
| Document Q&A (RAG)20,000 questions a month over retrieved documents, 12,000 in and 600 out; 30% cached | $926 | $494 | $432 |
| Coding agent400 tasks a month, 40 steps each with a growing context; 85% cached | $738 | $449 | $289 |
How they differ
- Gemini 3.1 Pro is cheaper on input ($2 vs $4).
- Gemini 3.1 Pro is cheaper on output ($12 vs $20), which matters most for long answers and reasoning models.
- Gemini 3.1 Pro accepts longer prompts (1M vs 1M tokens).
- On the Arena text leaderboard (25 Sep 2026), Claude Opus 5.5 scores higher (1509 vs 1487). Test both on your own prompts before deciding.
Recent changes
All changes- ▼ 20%Claude Opus 5.5 launched at $4 / $20 per 1M tokens, 20% below Opus 5.
- Anthropic retired Claude Opus 4.1.
- Anthropic launched Claude Opus 5 at $5 / $25.
- Anthropic retired Claude Opus 4 and Claude Sonnet 4.
