Claude Opus 4.1 vs Mercury 2
Claude Opus 4.1 leads Mercury 2 on the Artificial Analysis Intelligence Index, 22.8 to 10.8, and Mercury 2 costs 100.0x less per output token ($0.75 vs $75.00 per million). Updated October 22, 2026; 31 benchmarks have a result for both.
Claude Opus 4.1 or Mercury 2: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Claude Opus 4.1 for a larger context window (200K against 128K tokens).
- Shared results
- 31
- Claude Opus 4.1 only
- 42
- Mercury 2 only
- 11
- Like-for-like categories
- 6 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Intelligence
AA Intelligence Index
Claude Opus 4.1
Claude Opus 4.1 leads, 22.8 against 10.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Mercury 2 has a AA Agentic Index result, 1.6.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.1 has a GPQA Diamond result, 76.3%.
Directional only
Math
AIME
No call
Only Claude Opus 4.1 has a AIME result, 78.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.1 has a MMLU Pro result, 87.9%.
Directional only
Web design
Design Arena: websites
Claude Opus 4.1
Claude Opus 4.1 leads, 1176 against 1036.
Same board, both measured
Long documents
Listed context window
Claude Opus 4.1
Claude Opus 4.1 takes 200K tokens against 128K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mercury 2
Claude Opus 4.1 $0.052, Mercury 2 $0.0006 per turn.
List prices
At a glance
- Coding index
- Claude Opus 4.1 not benchmarked, Mercury 2 not benchmarked.
- Widest category
- Web design, 20.3 points apart on average over 8 shared benchmarks.
- Widest single gap
- LMArena WebDev: HTML: Claude Opus 4.1 1399 against Mercury 2 1199, 33.3 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.1 $75.00 against Mercury 2 $0.75 per million output tokens, 100.0x apart.
- Context window
- Claude Opus 4.1 takes 200K tokens, Mercury 2 128K.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Claude Opus 4.1 | Bars | Mercury 2 | Ties |
|---|---|---|---|---|
| Coding | 5 | 0 | ||
| Intelligence | 1 | 0 | ||
| Reasoning | 3 | 0 | ||
| Knowledge | 3 | 0 | ||
| Web design | 8 | 0 | ||
| General | 11 | 0 | ||
| All shared boards | 31 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index50
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| LMArena WebDev | 1390 | 1171 | Claude Opus 4.1 |
| AA Coding Index | Not measured | 31.1 | Only Mercury 2 measured |
| LiveCodeBench (Vals AI) | 66.5% | Not measured | Only Claude Opus 4.1 measured |
| SciCode | Not measured | 37.7% | Only Mercury 2 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 26.5% | Only Mercury 2 measured |
| Terminal-Bench | 38.0% | Not measured | Only Claude Opus 4.1 measured |
| WeirdML | 45.9% | 43.2% | Claude Opus 4.1 |
| Cybench | 42.0% | Not measured | Only Claude Opus 4.1 measured |
| ALE-Bench | Not measured | 785.6 | Only Mercury 2 measured |
| LMArena Text: coding | 1479 | 1390 | Claude Opus 4.1 |
| LMArena Text: software and IT | 1456 | 1385 | Claude Opus 4.1 |
| LMArena WebDev: React | Not measured | 1160 | Only Mercury 2 measured |
| LMArena WebDev: HTML | 1399 | 1199 | Claude Opus 4.1 |
| SciCode | 4.6% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 25 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| AA Intelligence Index | 22.8 | 10.8 | Claude Opus 4.1 |
| Epoch Capabilities Index | 144.1 | Not measured | Only Claude Opus 4.1 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 1.6 | Only Mercury 2 measured |
| τ²-Bench Telecom | Not measured | 70.8% | Only Mercury 2 measured |
| METR time horizons | 66.8% | Not measured | Only Claude Opus 4.1 measured |
| GDPval | 43.6% | Not measured | Only Claude Opus 4.1 measured |
| DeepResearch Bench | 48.3% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 36 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| GPQA Diamond | 76.3% | Not measured | Only Claude Opus 4.1 measured |
| MMMU Pro (Vals AI) | 77.5% | Not measured | Only Claude Opus 4.1 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 77.0% | Only Mercury 2 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 17.1% | Only Mercury 2 measured |
| GPQA Diamond (Epoch AI run) | 77.3% | Not measured | Only Claude Opus 4.1 measured |
| SimpleBench | 60.0% | Not measured | Only Claude Opus 4.1 measured |
| Mystery game puzzles | 21.0% | Not measured | Only Claude Opus 4.1 measured |
| EBR-bench | 7.9% | Not measured | Only Claude Opus 4.1 measured |
| VPCT | 35.0% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: hard prompts | 1442 | 1362 | Claude Opus 4.1 |
| LMArena Text: expert | 1438 | 1358 | Claude Opus 4.1 |
| LMArena Text: hard prompts in English | 1451 | 1374 | Claude Opus 4.1 |
| Neither model has a result on the other 10 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| AIME | 78.2% | Not measured | Only Claude Opus 4.1 measured |
| MATH 500 (Vals AI) | 95.4% | Not measured | Only Claude Opus 4.1 measured |
| MGSM (Vals AI) | 94.4% | Not measured | Only Claude Opus 4.1 measured |
| OTIS Mock AIME | 68.9% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tiers 1 to 3 | 12.6% | Not measured | Only Claude Opus 4.1 measured |
| FrontierMath, tier 4 | 2.4% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: math | 1431 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: mathematical work | 1434 | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 5 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| MMLU Pro | 87.9% | Not measured | Only Claude Opus 4.1 measured |
| LegalBench (Vals AI) | 83.5% | Not measured | Only Claude Opus 4.1 measured |
| TaxEval (Vals AI) | 73.7% | Not measured | Only Claude Opus 4.1 measured |
| MortgageTax (Vals AI) | 61.1% | Not measured | Only Claude Opus 4.1 measured |
| MedQA (Vals AI) | 93.6% | Not measured | Only Claude Opus 4.1 measured |
| MedCode (Vals AI) | 47.2% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: science | 1422 | 1343 | Claude Opus 4.1 |
| LMArena Text: medicine and healthcare | 1416 | 1363 | Claude Opus 4.1 |
| LMArena Text: legal and government | 1421 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: business and finance | 1406 | 1349 | Claude Opus 4.1 |
| FACTS Benchmark Suite | 40.4% | Not measured | Only Claude Opus 4.1 measured |
| Neither model has a result on the other 7 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index80
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| Design Arena: websites | 1176 | 1036 | Claude Opus 4.1 |
| Design Arena: UI components | 1162 | 996 | Claude Opus 4.1 |
| Design Arena: game dev | 1171 | 984 | Claude Opus 4.1 |
| Design Arena: data viz | 1166 | 1009 | Claude Opus 4.1 |
| Design Arena: 3D | 1152 | 982 | Claude Opus 4.1 |
| Design Arena: all code categories | 1170 | 1021 | Claude Opus 4.1 |
| Design Arena: SVG | 1152 | 998 | Claude Opus 4.1 |
| Design Arena: ASCII art | 1167 | 988 | Claude Opus 4.1 |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index110
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 31.4% | Not measured | Only Claude Opus 4.1 measured |
| MedScribe (Vals AI) | 73.9% | Not measured | Only Claude Opus 4.1 measured |
| IFBench | Not measured | 69.8% | Only Mercury 2 measured |
| Long context reasoning (AA-LCR) | Not measured | 43.7% | Only Mercury 2 measured |
| DTBench | 80.0% | Not measured | Only Claude Opus 4.1 measured |
| LMCA | 37.1% | Not measured | Only Claude Opus 4.1 measured |
| Creative writing (Lech Mazur) | 84.7% | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text | 1419 | 1354 | Claude Opus 4.1 |
| LMArena Text: instruction following | 1435 | 1328 | Claude Opus 4.1 |
| LMArena Text: creative writing | 1412 | 1286 | Claude Opus 4.1 |
| LMArena Text: English | 1433 | 1378 | Claude Opus 4.1 |
| LMArena Text: non-English | 1405 | 1330 | Claude Opus 4.1 |
| LMArena Text: Chinese | 1427 | 1414 | Claude Opus 4.1 |
| LMArena Text: German | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Japanese | 1377 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Korean | 1381 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: French | 1433 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Spanish | 1448 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: Russian | 1422 | 1304 | Claude Opus 4.1 |
| LMArena Text: Polish | 1413 | Not measured | Only Claude Opus 4.1 measured |
| LMArena Text: multi-turn | 1444 | 1357 | Claude Opus 4.1 |
| LMArena Text: longer queries | 1455 | 1329 | Claude Opus 4.1 |
| LMArena Text: writing and language | 1418 | 1300 | Claude Opus 4.1 |
| LMArena Text: entertainment and media | 1398 | 1314 | Claude Opus 4.1 |
| Neither model has a result on the other 22 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.1 | Mercury 2 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Mercury 2 costs less
Repository review
50K input + 3K output tokens
Mercury 2 costs less
Agent loop
200K input + 10K output tokens
Mercury 2 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Anthropic Claude Opus 4.1 | Inception Mercury 2 |
|---|---|---|
| Maker | Anthropic | Inception |
| Weights | No public weights listed | No public weights listed |
| Released | August 5, 2025 | March 4, 2026 |
| Context window | 200K | 128K |
| Input $/Mtok | $15.00 | $0.25 |
| Output $/Mtok | $75.00 | $0.75 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 1 | 1 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.1 better than Mercury 2 for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Claude Opus 4.1 for a larger context window (200K against 128K tokens).
Which is cheaper, Claude Opus 4.1 or Mercury 2?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Mercury 2 costs $0.25 and $0.75. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Opus 4.1 or Mercury 2?
Claude Opus 4.1, with 200K tokens against 128K.
How many benchmarks is the Claude Opus 4.1 vs Mercury 2 comparison based on?
31 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and Mercury 2's on 1. Where only one model has a result, the page says so instead of naming a winner.