Standard Compute
Model comparison 2026

Claude Opus 5.5 vs Gemini 3.1 Pro

Claude Opus 5.5
Anthropic · Frontier · Proprietary
$8.80/1M · 1M ctx
Gemini 3.1 Pro
Google · Frontier · Proprietary
$5.00/1M · 1.0M ctx

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality
Correctness and depth of what it produces
Agentic Ability
Tool calls, instruction-following, and multi-step tasks
Speed
Tokens per second and time-to-first-token
Value for money
How much capability you get per dollar
Reliability
Consistent results: fewer refusals, loops and format breaks

Specs and pricing side by side

Spec
Opus 5.5
Gemini 3.1 Pro
Maker
Anthropic
Google
Blended price / 1M
$8.80
$5.00
Input / output
$4.00 in · $20 out / 1M tokens
$2.00 in · $12 out / 1M tokens
Context window
1M
1.0M
Open weights
No
No
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
10.0
9.2
Agentic Ability
10.0
9.0
Speed
7.6
7.5
Value for money
7.4
8.1
Reliability
9.5
8.8

Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).

Verdict: Opus 5.5 or Gemini 3.1 Pro?

Updated 2026-10-13

Choose Claude Opus 5.5 if you want the hardest coding and agent work, as the default flagship instead of Fable. Choose Gemini 3.1 Pro if you want huge-context and multimodal work, and Gemini CLI users.

In our editorial scoring, Claude Opus 5.5 leads in 4 of five dimensions (output quality, agentic ability, speed and reliability), while Gemini 3.1 Pro leads in 1. On price, Claude Opus 5.5 runs about $8.80 per 1M tokens (blended) and is proprietary; Gemini 3.1 Pro is about $5.00 and proprietary.

Where Opus 5.5 falls short
  • Twice Sonnet 5.5's price per token for a small measured gain
  • Released September 2026, so its long-run track record is still short
Full Opus 5.5 breakdown →
Where Gemini 3.1 Pro falls short
  • Tool use a touch behind Claude/GPT on some agents
  • Preview-tier stability varies
Full Gemini 3.1 Pro breakdown →

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