Claude Opus 4.8 vs Gemini 3.1 Pro

Claude Opus 4.8 versus Gemini 3.1 Pro specifications and price.
metric	Claude Opus 4.8	Gemini 3.1 Pro
Input / 1M	$5.00	$2.00
Output / 1M	$25.00	$12.00
Context	1M	1.0M
Cost @ typical workload	$4,000/mo	$1,800/mo
Modality	text + image	text + image + audio + video
Price source	list	list
Provider	Anthropic	Google

Which should you pick?

On a typical workload, Gemini 3.1 Pro costs $1,800/mo against Claude Opus 4.8's $4,000/mo — roughly 2.2× cheaper. But the ranking depends on your output-to-input ratio: output is the pricier direction for both, so an output-heavy job (code generation, long answers) widens the gap while an input-heavy one (summarization, retrieval) narrows it. If you need to fit more in a single prompt, Gemini 3.1 Pro has the larger 1.0M-token window (~1,573 pages).

These are list and routed market prices, not measured outcomes. Two models at the same rate can still cost different amounts to finish the same task, because verbose or reasoning-heavy models emit more tokens. That gap is exactly what measured cost-per-task captures.

Frequently asked questions

Is Claude Opus 4.8 or Gemini 3.1 Pro cheaper?

For a typical workload (1,500 input + 500 output tokens × 200,000 requests/month), Gemini 3.1 Pro costs $1,800/mo versus $4,000/mo for Claude Opus 4.8 — about 2.2× less. Because output is priced higher than input, the winner can flip if your workload writes much more or less than this; check your own numbers in the calculator.

What's the main difference between Claude Opus 4.8 and Gemini 3.1 Pro?

On price, Claude Opus 4.8 is $5.00/$25.00 per 1M (in/out) and Gemini 3.1 Pro is $2.00/$12.00. Gemini 3.1 Pro has the larger context window at 1.0M tokens.

More comparisons

Claude Opus 4.8 and Gemini 3.1 Pro — full specs and price history.
API cost calculator — compare on your own workload.
All comparisons — the full head-to-head index.