Claude Opus 4.8 vs Gemini 3.1 Pro
Side-by-side comparison of pricing, context window, modalities, licensing, and strengths — with practical guidance on which model fits which workload.
| Spec | Claude Opus 4.8 | Gemini 3.1 Pro |
|---|---|---|
| Provider | Anthropic | |
| Context window | 1M tokens | 1M tokens |
| Input price (per 1M tokens) | $5.00 | $2.00 |
| Output price (per 1M tokens) | $25.00 | $12.00 |
| Example workload (10M in + 2M out) | $100.00 / month | $44.00 / month |
| Modalities | text, image, code | text, image, audio, video, code |
| Knowledge cutoff | Not disclosed | Not disclosed |
| Release date | 2026 | 2026 |
| License | Proprietary | Proprietary |
| Strengths | Long-horizon agents, Coding, Knowledge work, Clear writing | Multimodal reasoning, Computer use, Video input, Long context |
| Open weights | No | No |
Verdict
Anthropic’s agentic specialist against Google’s multimodal generalist. Gemini 3.1 Pro is cheaper per token ($2/$12 vs $5/$25) and accepts video, but its output caps at 64K tokens and pricing steps up past 200K input. Claude Opus 4.8 offers 128K output, flat 1M-context pricing, and is widely preferred for sustained autonomous coding and careful long-form reasoning — many teams ingest huge material with Gemini and hand the high-stakes synthesis to Opus.
When to choose Claude Opus 4.8
Pick Claude Opus 4.8 for complex refactors, long agentic sessions, and the largest single-response outputs (128K tokens).
When to choose Gemini 3.1 Pro
Pick Gemini 3.1 Pro for video/audio inputs, computer use, and flagship quality at a markedly lower sticker price.
Prices and specs reflect published provider information and change frequently — always confirm on the provider's pricing page before committing to a workload.
Frequently asked questions
Which is cheaper: Claude Opus 4.8 or Gemini 3.1 Pro?
Gemini 3.1 Pro is cheaper per token: $2.00 input / $12.00 output per 1M tokens, versus $5.00 / $25.00 for Claude Opus 4.8. Actual costs depend on your input-to-output ratio — try the AI cost calculator for your own numbers.
Which has the larger context window?
Gemini 3.1 Pro supports 1M tokens versus 1M for Claude Opus 4.8 — roughly 1.0× more room for documents, code, and conversation history.
Can I self-host either model?
No — both models are proprietary and available only through their providers' APIs or cloud platforms.
How should I test which model is better for my use case?
Benchmarks are a starting point, not an answer. Run both models on 20–50 examples of your real task and compare outputs blind. Use our token counter to estimate prompt sizes and the cost calculator to project monthly spend before committing.