Head-to-head
Mistral Large 3 vs Claude Opus 4.5: which AI model wins in 2026?
Mistral Large 3 ($1.50/1M out) and Claude Opus 4.5 ($25/1M out) are two of the most-used AI models in 2026. Compare them line by line below, then cast your verdict.
Quick verdict
On Reasoning, pick Claude Opus 4.5: the arena rates it 3.5/5 against 3/5 for Mistral Large 3. On budget, Mistral Large 3 wins: it starts at $1.50/1M out versus $25/1M out for Claude Opus 4.5.
Line-by-line comparison
Strengths and weaknesses
Mistral Large 3
- Apache 2.0 open weights with single-node deployment via FP8/NVFP4 quantization, despite 675B total parameters
- 256K context window, at the upper end for open-weight models, well suited to long-document RAG
- Aggressive flagship pricing at $0.50 in / $1.50 out per 1M tokens, roughly 3-4x cheaper than Western proprietary flagships
- Debuted #2 among open-source non-reasoning models on LMArena (Elo ~1418)
- Native multimodality (2.5B-parameter vision encoder) and 40+ native languages
- Developers on HN praise its strict formatting and instruction following plus production reliability
- Weak deep reasoning: GPQA Diamond ~44% vs high-70s for DeepSeek V3.2 and Kimi K2 Thinking; no reasoning variant at launch
- Trails GLM-4.6, Kimi K2 and DeepSeek on modern coding benchmarks (middling LiveCodeBench v6); HN devs place it a 'different weight class' below Gemini 3, GPT-5.1 and Claude Opus 4.5
- Hallucination-prone on factual QA (SimpleQA ~24%) with weak abstention tuning
- Measured output speed ~49 tok/s on Artificial Analysis, below the ~58 tok/s median for comparable models
- HN criticism that the architecture closely mirrors DeepSeek V3, raising doubts about original R&D
Claude Opus 4.5
- First model past 80% on SWE-bench Verified (80.9% at launch), beating Gemini 3 Pro and GPT-5.1 on real-world coding
- 66% price cut vs Opus 4.1 ($5/$25 vs $15/$75 per 1M tokens) made Opus-tier viable for production workloads
- 48-76% fewer output tokens than Sonnet 4.5 at matched or better quality, compounding the price cut
- Effort parameter (introduced with this model) lets devs trade reasoning depth for cost and latency per call
- Strong hands-on reports: one-shot complex refactors, caught race conditions other models missed, converged in ~4 agentic iterations vs ~10 for rivals
- +29% on Vending-Bench vs Sonnet 4.5, with fewer dead-ends on long-horizon autonomous tasks
- 200K context window only (64K max output), far behind the 1M of Gemini 3 Pro and later Claude models; users reported selective attention above ~70% context fill
- Gated to $100-200/month Max tiers in Claude apps at launch; Pro subscribers were locked out and heavy users still hit limits (HN called it 'penny-wise and pound-foolish')
- Moderate latency; extended thinking adds cost and delay on simple tasks
- Superseded since early 2026: Opus 4.6/4.7/4.8 cost the same $5/$25 with 1M context and higher benchmarks, leaving 4.5 no price advantage
- Legacy API surface: manual budget_tokens extended thinking rather than the adaptive thinking of newer Claude models
Cast your verdict
One recommendation per tool per gladiator. It reshapes the crowd score everyone sees.
The arena’s verdict on Mistral Large 3
Choose Mistral Large 3 if you want an open-weight, EU-governed flagship for multilingual RAG, long-document work, or self-hosted deployments: versus Mistral Large 2 (dense 123B, restrictive research license, $2/$6 API pricing) it is a clear upgrade in context, multimodality, licensing, and cost. Avoid it as your primary coding or deep-reasoning engine; DeepSeek V3.2, GLM-4.6, or proprietary frontier models score materially higher there. Treat it as a cheap, reliable workhorse rather than a frontier performer.
The arena’s verdict on Claude Opus 4.5
Pick Claude Opus 4.5 only if you have a workload already tuned and pinned to this snapshot (claude-opus-4-5-20251101) and need stability. It was a landmark release, the first past 80% on SWE-bench Verified and a 66% price cut over Opus 4.1, but Anthropic now sells Opus 4.6 through 4.8 at the identical $5/$25 rate with a 1M context window and better scores. Anyone starting a new project should choose Opus 4.8 instead, and cost-sensitive users get near-Opus coding from Sonnet 5 at $3/$15 (intro $2/$10 through Aug 2026). Avoid it entirely if your prompts approach the 200K context ceiling.
Keep comparing
Frequently asked questions
Is Mistral Large 3 better than Claude Opus 4.5?
On Reasoning, Claude Opus 4.5 rates higher (3.5/5 vs 3/5). The right pick depends on your use case. The line-by-line comparison on this page breaks down pricing, key specs and arena ratings.
Which is cheaper, Mistral Large 3 or Claude Opus 4.5?
Mistral Large 3 is cheaper: it starts at $1.50/1M out, while Claude Opus 4.5 starts at $25/1M out.
How much do Mistral Large 3 and Claude Opus 4.5 cost per 1M tokens?
Mistral Large 3: $0.50/1M in per 1M input tokens, $1.50/1M out per 1M output tokens. Claude Opus 4.5: $5/1M in per 1M input tokens, $25/1M out per 1M output tokens.