Model comparison
Claude Opus 4.1 vs Mercury 2.5
Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 33.5 on the Noometry Index. Mercury 2.5 costs 444× less per token, which makes it the better buy when Claude Opus 4.1's lead doesn't matter for your workload.
Last verified . 1 shared benchmarks.
Summary
- They share 1 benchmark with published results for both. Claude Opus 4.1 scores higher in 2 categories and Mercury 2.5 in 1 category; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 4.1 leads 32.2 to 22.4.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $15 / $75 for Claude Opus 4.1.
- Mercury 2.5 accepts more context: 260K tokens versus 200K.
Side by side
| Claude Opus 4.1 | Mercury 2.5 | |
|---|---|---|
| Provider | Anthropic | Inception |
| Noometry Index | 41.0 | 33.5 |
| Released | 2025-08-05 | 2026-09-08 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 260K |
| Max output | 32K | 66K |
| Input $ / M tokens | $15 | $0.04 |
| Output $ / M tokens | $75 | $0.15 |
| Results tracked | 48 | 4 |
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Category by category
Coding Claude Opus 4.1 leads
Claude Opus 4.1: 44.4 (#73), Mercury 2.5: 39.5 (#156)
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| ALE-Bench | 674.77 | 301.65 |
| SWE-bench Verified | 73.3% | — |
| LMArena WebDev | 1390 | — |
| SciCode | — | 38.5% |
| WeirdML | 45.9% | — |
| LMArena Coding | 1479 | — |
| AlgoTune | 1.34 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.1: 35.0 (#41), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| Terminal-Bench | 38% | — |
| GDPval | 43.6% | — |
| Cybench | 42% | — |
| DeepResearch Bench | 48.3% | — |
| LMArena Search | 1148 | — |
| METR Time Horizons | 66.8% | — |
Reasoning Claude Opus 4.1 leads
Claude Opus 4.1: 32.2 (#76), Mercury 2.5: 22.4 (#193)
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| SimpleBench | 60% | — |
| CritPt | — | 0% |
| Chess Puzzles | 7% | — |
| EnigmaEval | 7.2% | — |
| EBR-Bench | 7.9% | — |
| LMArena Hard Prompts | 1443 | — |
| Mystery Game Puzzles | 21% | — |
| DTBench | 80% | — |
| LMCA | 37.1% | — |
| Epoch Capabilities Index | 144.12 | — |
| ForecastBench | 62 | — |
Math Too close to call
Claude Opus 4.1: 22.3 (#277), Mercury 2.5: 23.3 (#272)
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 12.6% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 68.9% | — |
| ProofBench | — | 3% |
| LMArena Math | 1431 | — |
| FrontierMath (Feb 2025 set) | 7.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Not comparable
Claude Opus 4.1: 42.0 (#101), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| GPQA Diamond | 77.3% | — |
| Humanity's Last Exam | 11.5% | — |
| Confabulations | 17.1% | — |
| Vectara Hallucination Rate | 11.8% | — |
| LMArena Expert | 1439 | — |
Multimodal Not comparable
Claude Opus 4.1: 26.8 (#119), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| VPCT | 35% | — |
Multilingual Not comparable
Claude Opus 4.1: 52.0 (#95), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1405 | — |
| LMArena Chinese | 1427 | — |
| LMArena French | 1431 | — |
| LMArena German | 1413 | — |
| LMArena Japanese | 1378 | — |
| LMArena Korean | 1380 | — |
| LMArena Russian | 1422 | — |
| LMArena Spanish | 1448 | — |
Instruction Following Not comparable
Claude Opus 4.1: 75.6 (#58), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1435 | — |
Long Context Not comparable
Claude Opus 4.1: 44.5 (#63), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1455 | — |
Writing & Preference Not comparable
Claude Opus 4.1: 62.4 (#74), Mercury 2.5: —
| Benchmark | Claude Opus 4.1 | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1419 | — |
| LMArena Creative Writing | 1412 | — |
| Short-Story Creative Writing | 84.7% | — |
| LMArena Multi-Turn | 1444 | — |
Frequently asked questions
Is Claude Opus 4.1 better than Mercury 2.5?
Claude Opus 4.1 is the stronger model overall, scoring 41.0 to 33.5 on the Noometry Index. Mercury 2.5 costs 444× less per token, which makes it the better buy when Claude Opus 4.1's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 4.1 or Mercury 2.5?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; Claude Opus 4.1 lists at $15 and $75.
Is Claude Opus 4.1 or Mercury 2.5 better for coding?
Claude Opus 4.1 scores higher on coding benchmarks: 44.4 versus 39.5 in the Noometry coding category.
Which has the bigger context window?
Mercury 2.5 does, with 260K tokens against 200K.
How many benchmarks do Claude Opus 4.1 and Mercury 2.5 share?
1 benchmark has published results for both models. Claude Opus 4.1 has 48 scored results on Noometry and Mercury 2.5 has 4.