Claude Opus 5.5 vs Gemini 3.1 Pro (preview)
There is no quality verdict yet: the AIGROW small-business benchmark has not run Claude Opus 5.5. On price, Gemini 3.1 Pro (preview) costs less: $2 in and $12 out per million tokens, against $4 in and $20 out for Claude Opus 5.5.
Gemini 3.1 Pro is still a preview, so its price can change. US dollars, standard rate, shortest context band. Price only: the benchmark has not run both. Newer comparison: Gemini 4 Argon vs Claude Opus 5.5
- Claude Opus 5.5
- $20.00
- Gemini 3.1 Pro (preview)
- $10.80
- Claude Opus 5.5, per M tokens
- $4 / $20
- Gemini 3.1 Pro (preview), per M tokens
- $2 / $12
3,000 tokens in and 400 out each, at list price.
Anthropic's default flagship against Google's strongest model, with Gemini cheaper on input and output. 1,000 support replies cost $20.00 on Claude Opus 5.5 and $10.80 on Gemini 3.1 Pro (preview), so Claude Opus 5.5 costs 85% more. Claude Opus 5.5 was released on 22 Sep 2026, Gemini 3.1 Pro (preview) was released on 19 Feb 2026.
What each one costs
The API price per million tokens and the cheapest app plan with each model, from the makers’ own pages. Each name opens that model’s full price page.
- Claude Opus 5.5
- On the Anthropic API, Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens. In Claude, the cheapest plan with it is Pro at $20/mo. Plan prices read 20 October 2026. AIGROW API credit runs Claude Opus 5.5 at $1.00 / $5.00 per million input / output tokens, up to 75% below list price. See API credit
- Gemini 3.1 Pro (preview)
- On the Google API, Gemini 3.1 Pro (preview) costs $2 per million input tokens and $12 per million output tokens. In Gemini, the cheapest plan with it is Google AI Pro at $19.99/mo. Plan prices read 20 October 2026.
Side by side
Each maker’s published rate for its standard tier. Cached input is what a repeated prompt prefix costs once the provider has stored it.
| Fact | Claude Opus 5.5 | Gemini 3.1 Pro (preview) |
|---|---|---|
| Maker | Anthropic | |
| Tier | Flagships | Flagships |
| Input, per M tokens | $4.00 | $2.00 |
| Output, per M tokens | $20.00 | $12.00 |
| Cached input | $0.20 | $0.20 |
| Context window | 1M | 1.05M |
| Released | 22 Sep 2026 | 19 Feb 2026 |
| Weights | Closed weights | Closed weights |
What a job costs on each
1,000 runs of each job at the two list prices. The gap moves from job to job because the models price input, output and cached context differently.
| Job | Claude Opus 5.5 | Gemini 3.1 Pro (preview) | Cheaper |
|---|---|---|---|
| Support reply3,000 in, 400 out. | $20.00 | $10.80 | Gemini 3.1 Pro (preview), 46% less |
| Document summary25,000 in, 1,000 out. | $120 | $62.00 | Gemini 3.1 Pro (preview), 48% less |
| Agent task80,000 in (70,000 cached), 3,000 out. | $114 | $70.00 | Gemini 3.1 Pro (preview), 39% less |
The token counts are ours, chosen to look like real work; the prices are the makers’. A model with no published cache price bills the agent task’s repeated context at its full input rate.
The small print
What each base rate leaves out, from the makers’ own pages: surcharges, discounts, promotions and cache pricing.
- Claude Opus 5.5
- Cache read is 0.05x input on this model ($0.20). Cache write $5 (5 min) or $8 (1 h). Fast mode $8 / $40. Batch API 50% off. US-only inference bills 1.1x. Full context window billed at standard rates. Max output 128K. Anthropic’s pricing page
- Gemini 3.1 Pro (preview)
- Preview model, but Google has no GA 3.x Pro and it is widely used. Prompts above 200K tokens: $4 / $18, cached $0.40. Cache storage $4.50 per MTok per hour. Batch 50% off. Max output 65,536. Google’s pricing page
Other comparisons
Every head to head on the list that involves Claude Opus 5.5 or Gemini 3.1 Pro (preview).
- Gemini 4 Argon vs Claude Opus 5.5
- Gemini 4 Argon vs Gemini 3.1 Pro (preview)
- Muse Wonder vs Claude Opus 5.5
- Claude Opus 5.5 vs GPT-6 Astra
- Claude Opus 5.5 vs Claude Opus 5
- Claude Sonnet 5.5 vs Claude Opus 5.5
- Claude Fable 5.1 vs Claude Opus 5.5
- Claude Opus 5.5 vs GPT-6.1 Sol
Run Claude Opus 5.5 up to 75% below list price
AIGROW API credit covers Claude Opus 5.5 at published rates never above the list prices here, and $25 buys $100 of credit.
Prices checked 15 October 2026