Claude Opus 4.8 vs Gemini 3.1 Pro Preview: price, scores, context

Side-by-side comparison

Criterion	Claude Opus 4.8	Gemini 3.1 Pro Preview
Developer	Anthropic	Google DeepMind
Released	May 28, 2026	February 19, 2026
Capability index	83.4 / 100	79.3 / 100
Input price	$5	$2
Output price	$25	$12
Cost of a typical task	$0.15	$0.064
Context window	1,000,000 tokens	1,048,576 tokens
Maximum output	128,000 tokens	65,536 tokens
Reasoning mode	Yes	Yes
Tool calling	Yes	Yes
Accepted inputs	text, image, PDF	text, image, video, audio, PDF
Open weights	No	No
Knowledge cutoff	January 2026	January 2025

What are we comparing?

Claude Opus 4.8 and Gemini 3.1 Pro Preview are two mid-range models, balancing quality and cost, one from Anthropic, the other from Google DeepMind. Claude Opus 4.8 was released on May 28, 2026, Gemini 3.1 Pro Preview on February 19, 2026.

All figures below come from public sources checked on October 22, 2026: models.dev and OpenRouter for prices and capabilities, Epoch AI for scores.

Performance

On our capability index, Claude Opus 4.8 scores 83.4 out of 100 and Gemini 3.1 Pro Preview 79.3. Claude Opus 4.8 leads by 4.1 points.

On the 4 benchmarks reported for both, Claude Opus 4.8 wins 3 times and Gemini 3.1 Pro Preview 1:

GPQA Diamond (PhD-level science questions): Claude Opus 4.8 91%, Gemini 3.1 Pro Preview 94.4%
OTIS Mock AIME (competition mathematics problems): Claude Opus 4.8 98.3%, Gemini 3.1 Pro Preview 95.6%
FrontierMath (very hard research-level mathematics): Claude Opus 4.8 80%, Gemini 3.1 Pro Preview 59.6%
APEX-Agents (professional tasks carried out by an agent): Claude Opus 4.8 48.9%, Gemini 3.1 Pro Preview 35.1%

Which one costs less?

Claude Opus 4.8 costs $5 per million input tokens and $25 per million output tokens; Gemini 3.1 Pro Preview costs $2 and $12.

For a typical agent task (read 20,000 tokens, write 2,000), expect $0.15 with Claude Opus 4.8 versus $0.064 with Gemini 3.1 Pro Preview. Gemini 3.1 Pro Preview is 2.3 times cheaper, a gap that adds up quickly over 1,000 tasks: $86 difference.

Run the numbers with your own volumes in the agent cost calculator.

Context and capabilities

Gemini 3.1 Pro Preview reads more in one go: 1,048,576 tokens of context (roughly 1,573 pages), versus 1,000,000 for Claude Opus 4.8.

Reasoning mode: Claude Opus 4.8 yes, Gemini 3.1 Pro Preview yes. Tool calling: Claude Opus 4.8 yes, Gemini 3.1 Pro Preview yes. Image input: Claude Opus 4.8 yes, Gemini 3.1 Pro Preview yes.

Neither publishes its weights: both are used through an API.

Knowledge cutoff: January 2026 for Claude Opus 4.8, January 2025 for Gemini 3.1 Pro Preview.

In short

Our reading of the data:

Choose Claude Opus 4.8 for a higher capability index and a more recent release.
Choose Gemini 3.1 Pro Preview for a lower cost.

This verdict relies on public figures; it does not replace a trial on your own tasks.

Frequently asked questions

Claude Opus 4.8 or Gemini 3.1 Pro Preview: which is better?

On our index (Epoch AI data), Claude Opus 4.8 scores 83.4 and Gemini 3.1 Pro Preview 79.3 out of 100. The best choice also depends on price and on your use case.

Which one is cheaper?

Gemini 3.1 Pro Preview. To read 20,000 tokens and write 2,000, expect $0.15 with Claude Opus 4.8 and $0.064 with Gemini 3.1 Pro Preview (prices as of October 22, 2026).

Which one has the larger context window?

Gemini 3.1 Pro Preview, with 1,048,576 tokens versus 1,000,000.

Can I run Claude Opus 4.8 or Gemini 3.1 Pro Preview on my own servers?

No: both are closed models, available through an API.

Claude Opus 4.8 versus Gemini 3.1 Pro Preview