Anthropic Claude Opus 4.8 (1M) vs Gemini 3.1 Flash
Side-by-side comparison of pricing, context window, capabilities, and a real-cost sample workload.
Option A
Anthropic Claude Opus 4.8 (1M)
by Anthropic
Context: 1M
Input: $5.00 / 1M
Output: $25.00 / 1M
Released: 2026-05
Option B
Gemini 3.1 Flash
by Google
Context: 1M
Input: $0.35 / 1M
Output: $1.40 / 1M
Released: 2026-03
Detailed Comparison
| Dimension | Anthropic Claude Opus 4.8 (1M) | Gemini 3.1 Flash |
|---|---|---|
| Provider | Anthropic | |
| Context window TieTie | 1M | 1M |
| Input price ($/1M) Winner | $5.00 | $0.35 |
| Output price ($/1M) Winner | $25.00 | $1.40 |
| Sample workload cost Winner 1M input + 500K output tokens
|
$17.50 | $1.05 |
| Released Winner | 2026-05 | 2026-03 |
| Tokenizer | claude-4 | gemini |
The verdict
On the dimensions we measured, Gemini 3.1 Flash wins more often - particularly on cost-effectiveness for a typical 1M+0.5M workload.
Anthropic Claude Opus 4.8 (1M) - Key features
Anthropic's most capable Opus-tier model - highly autonomous, state-of-the-art on long-horizon agentic work, knowledge work and memory, with clearer, warmer writing. 1M context at standard pricing.
- Adaptive thinking + effort (low→max)
- State-of-the-art long-horizon agents
- 128K max output tokens
- 1M token context window
- Strong code review & debugging
Gemini 3.1 Flash - Key features
Fast and affordable Gemini 3.1 Flash optimized for high-throughput applications at minimal cost.
- 1M context window
- Ultra-fast inference
- Very low cost
- Good reasoning
- High throughput
How to choose
- Pick the cheaper model if your workload is mostly straightforward classification, extraction, or summarization.
- Pick the bigger context if you process long documents, large codebases, or multi-document research.
- Pick the more recent release if you need state-of-the-art reasoning quality and don't mind paying a bit more.
- Use both via a routing layer - send simple tasks to the cheaper one and complex tasks to the smarter one. This is the highest-ROI optimization in production AI.
Estimate the real cost of either model for your prompts using our Token Calculator.