Claude Opus 5.5 vs Mistral Large 4
| Spec | Claude Opus 5.5 | Mistral Large 4 |
|---|---|---|
| Respan Index | 73.7 (#1) | 45.0 (#47) |
| Blended price per 1M | $4 | $1.05 |
| Context window | 1M | 1M |
| Input / output per 1M | $2 / $10 | $0.7 / $2.1 |
| Max output | 128K | - |
| Input | text, vision | text, vision |
| Released | 2026-09-22 | 2026-10-06 |
Respan Index by category
Each category is scored 0 to 100, and how far ahead the winner is. Leads under a point are close to even.
| Category | Claude Opus 5.5 | Mistral Large 4 |
|---|---|---|
| Coding | 66.8 Claude Opus 5.5 | 41.5 Mistral Large 4 |
| Agents | 79.2 Claude Opus 5.5 | 56.0 Mistral Large 4 |
| Reasoning | 83.9 Claude Opus 5.5 | 42.7 Mistral Large 4 |
| Knowledge & language | 70.4 Claude Opus 5.5 | 18.2 Mistral Large 4 |
| Human preference | 61.4 Claude Opus 5.5 | 54.3 Mistral Large 4 |
Benchmarks both report
Claude Opus 5.5 leads on 21 of the 21 benchmarks both report. Higher is better. Each score links to where it was published.
| Benchmark | Claude Opus 5.5 | Mistral Large 4 |
|---|---|---|
| Chess Puzzles (Epoch AI) | 67% | 33% |
| LMArena Agent (LMArena) | 0.2094 | -0.0602 |
| LMArena Elo | 1509 | 1432 |
| LMArena WebDev (LMArena) | 1810 | 1544 |
| LMArena Vision (LMArena) | 1293 | 1252 |
| APEX-Agents (Mercor) | 73.5% | 51.6% |
| FrontierMath Tier 4 v2 (Epoch AI) | 95% | 26.8% |
| FrontierMath Tiers 1-3 v2 (Epoch AI) | 91.2% | 58.6% |
| Furniture Assembly (Epoch AI) | 83.3% | 20.8% |
| GPQA Diamond | 90.6% | 88.1% |
| LiveBench Agentic Coding (LiveBench) | 71.7% | 57.2% |
| LiveBench Coding (LiveBench) | 89.3% | 77.2% |
| LiveBench Data Analysis (LiveBench) | 80.3% | 76.5% |
| LiveBench Instruction Following (LiveBench) | 67% | 64.8% |
| LiveBench Language (LiveBench) | 86.3% | 49.6% |
| LiveBench Mathematics (LiveBench) | 97.1% | 93.6% |
| LiveBench Reasoning (LiveBench) | 92.2% | 83.9% |
| Mystery Game Puzzles (Epoch AI) | 71% | 17% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 100% | 98.3% |
| SimpleQA Verified | 72.2% | 20% |
| Terminal-Bench 4.0 (Vals AI) | 65.2% | 27.8% |
FAQ
Is Claude Opus 5.5 better than Mistral Large 4?
Claude Opus 5.5 scores 73.7 on the Respan Index (#1), ahead of Mistral Large 4 at 45.0 (#47). Claude Opus 5.5 leads on 21 of the 21 benchmarks both report.
Which is cheaper, Claude Opus 5.5 or Mistral Large 4?
Claude Opus 5.5 lists at $2 input and $10 output per 1M tokens; Mistral Large 4 at $0.7 and $2.1. Mistral Large 4 is 3.8x cheaper per token at list price.
Which has the larger context window?
Both accept 1M tokens of context.