Compare / Claude Opus 4.5 vs Mercury 2
Claude Opus 4.5 vs Mercury 2
Which is cheaper, which is more capable, and which does better at each kind of work, from 16 results on 3 sources that measured both models.
Claude Opus 4.5 or Mercury 2? The short answer
- Mercury 2 is cheaper: $0.38 against $10.00 per million tokens, 27 times less.
- Claude Opus 4.5 scores higher on the Artificial Analysis Intelligence Index: 29.1 against 13.8.
- On our business benchmarks, Claude Opus 4.5 ranks higher for agents and tool use, reasoning and knowledge, writing and sticking to the facts.
At a glance
| Claude Opus 4.5 | Mercury 2 | |
|---|---|---|
| Price per million tokens | $5.00 in · $25.00 out | $0.25 in · $0.75 out |
| Blended (3 in : 1 out) | $10.00 | $0.38 |
| Cheapest host, blended | $10.00 (Claude Platform on AWS) | – |
| Intelligence Index | 29.1 | 13.8 |
| Spring Prompt overall | – | – |
| Output speed, tokens a second | – | – |
| Context window | 200,000 tokens | 128,000 tokens |
| Weights | Closed | Closed |
| Developer based in | the US | the US |
Prices are the developer's list price where we have read it, otherwise the typical host on OpenRouter; see every model's price. Intelligence and speed from Artificial Analysis.
Which is better for what
Each model's rank among models available today, for each kind of work, from our own benchmarks and licensed sources. The better rank is in green.
| Use case | Claude Opus 4.5 | Mercury 2 |
|---|---|---|
| Agents and tool useMulti-step tasks with tools: support desks, coding agents, function calls | 36 of 161 | 107 of 161 |
| Professional workReal tasks from banking, consulting and law, business documents and freelance projects | 28 of 51 | not measured |
| Reasoning and knowledgeHard questions across science, maths and general knowledge | 61 of 195 | 109 of 195 |
| WritingWhat people prefer in blind comparisons, and judged writing quality | 16 of 187 | 146 of 187 |
| Sticking to the factsSummarising without inventing things, and factual answers | 71 of 153 | 136 of 153 |
Every shared result
| Benchmark | Metric | Claude Opus 4.5 | Mercury 2 |
|---|---|---|---|
| Arena (formerly LMArena)reported | OverallArena rating | 1,459 | 1,368 |
| Arena (formerly LMArena)reported | Business, management and financeArena rating | 1,472 | 1,340 |
| Arena (formerly LMArena)reported | Creative writingArena rating | 1,469 | 1,292 |
| Arena (formerly LMArena)reported | Expert promptsArena rating | 1,503 | 1,348 |
| Arena (formerly LMArena)reported | Instruction followingArena rating | 1,483 | 1,327 |
| Arena (formerly LMArena)reported | OverallArena rating | 1,474 | 1,343 |
| Arena (formerly LMArena)reported | Writing, literature and languageArena rating | 1,467 | 1,307 |
| Artificial Analysisreported | Artificial Analysis Intelligence Indexindex score | 29.1 | 13.8 |
| Artificial Analysisreported | GPQA Diamond% of questions | 86.6% | 77.0% |
| Artificial Analysisreported | Humanity's Last Exam% of questions | 30.1% | 17.1% |
| Artificial Analysisreported | IFBench% of instructions | 58.0% | 69.8% |
| Artificial Analysisreported | Long-context reasoning (AA-LCR)% of questions | 77.3% | 43.7% |
| Artificial Analysisreported | Terminal-Bench Hard% of tasks | 47.0% | 26.5% |
| Artificial Analysisreported | Τ²-bench telecom% of tasks | 89.5% | 70.8% |
| Vectara Hallucination Leaderboardreported | Answer rate% of documents | 98.7% | 100.0% |
| Vectara Hallucination Leaderboardreported | Hallucination rate% of summaries | 10.9% | 12.3% |
Bold green marks the better value on that metric. Where a source reports ranges that overlap, the difference may not be meaningful; see the benchmark page for ranges.
Quick answers
Is Claude Opus 4.5 better than Mercury 2?
It depends on the task. Among models available today, on our benchmarks and licensed sources, Claude Opus 4.5 ranks higher for agents and tool use, reasoning and knowledge, writing and sticking to the facts.
Which is cheaper, Claude Opus 4.5 or Mercury 2?
Mercury 2 costs $0.38 per million tokens (three input to one output), against $10.00 for Claude Opus 4.5.
Run Claude Opus 4.5 and Mercury 2 on your own prompt
Benchmarks aren't your data. Try both side by side in the playground, with the cost of every answer.