Model comparison
Claude Opus 4.8 vs Mercury 2.5
Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 33.5 on the Noometry Index. Mercury 2.5 costs 148× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.
Last verified . 4 shared benchmarks.
Summary
- They share 4 benchmarks with published results for both. Claude Opus 4.8 scores higher in 3 categories and Mercury 2.5 in 0 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 4.8 leads 78.4 to 23.3.
- The biggest single-benchmark swing is ProofBench: 69% for Claude Opus 4.8 and 3% for Mercury 2.5.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $5 / $25 for Claude Opus 4.8.
- Claude Opus 4.8 accepts more context: 1M tokens versus 260K.
Side by side
| Claude Opus 4.8 | Mercury 2.5 | |
|---|---|---|
| Provider | Anthropic | Inception |
| Noometry Index | 60.7 | 33.5 |
| Released | 2026-05-28 | 2026-09-08 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 260K |
| Max output | 128K | 66K |
| Input $ / M tokens | $5 | $0.04 |
| Output $ / M tokens | $25 | $0.15 |
| Results tracked | 65 | 4 |
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Category by category
Coding Claude Opus 4.8 leads
Claude Opus 4.8: 59.9 (#12), Mercury 2.5: 39.5 (#156)
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| SciCode | 53.5% | 38.5% |
| ALE-Bench | 1,564 | 301.65 |
| DeepSWE | 59% | — |
| FrontierCode | 46.5% | — |
| LMArena WebDev | 1556 | — |
| GSO | 47.1% | — |
| WeirdML | 82.9% | — |
| LMArena Coding | 1490 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.8: 47.6 (#11), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| APEX-Agents | 48.9% | — |
| OSWorld 2.0 | 20.6% | — |
| Remote Labor Index | 8.3% | — |
| τ²-bench Banking | 39.7% | — |
| DeepResearch Bench | 50.2% | — |
| PostTrainBench | 33.8% | — |
| GBAEval | 70.9% | — |
| GDP.pdf | 24% | — |
| LMArena Search | 1204 | — |
| Vending-Bench 2 | 5,787 | — |
Reasoning Claude Opus 4.8 leads
Claude Opus 4.8: 64.7 (#16), Mercury 2.5: 22.4 (#193)
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| CritPt | 20.9% | 0% |
| ARC-AGI-2 | 72.1% | — |
| SimpleBench | 64.8% | — |
| Kagi LLM Benchmark | 88.8% | — |
| NYT Connections (extended) | 91.1% | — |
| ARC-AGI-1 | 92.5% | — |
| Chess Puzzles | 34% | — |
| EnigmaEval | 23.5% | — |
| EBR-Bench | 28.6% | — |
| LMArena Hard Prompts | 1482 | — |
| Mystery Game Puzzles | 36% | — |
| DTBench | 94.9% | — |
| LMCA | 57.5% | — |
| Surface Evolver Bench | 87.5% | — |
| Bench to the Future 3 | 0.14 | — |
| Epoch Capabilities Index | 158.21 | — |
| ForecastBench | 59.9 | — |
Math Claude Opus 4.8 leads
Claude Opus 4.8: 78.4 (#13), Mercury 2.5: 23.3 (#272)
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| ProofBench | 69% | 3% |
| FrontierMath (Tiers 1-3) | 80% | — |
| FrontierMath Tier 4 | 56.1% | — |
| MathArena Final-Answer Competitions | 91.8% | — |
| OTIS Mock AIME 2024-2025 | 98.3% | — |
| LMArena Math | 1487 | — |
| FrontierMath (Feb 2025 set) | 47.2% | — |
| FrontierMath Tier 4 (v1) | 31.3% | — |
Knowledge Not comparable
Claude Opus 4.8: 61.3 (#29), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| GPQA Diamond | 91% | — |
| SimpleQA Verified | 53% | — |
| LMArena Expert | 1502 | — |
Multimodal Not comparable
Claude Opus 4.8: 42.9 (#26), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| LMArena Vision | 1294 | — |
| Blueprint-Bench 2 | 14.5% | — |
| Furniture Assembly | 42.5% | — |
| LMArena Document | 1475 | — |
Multilingual Not comparable
Claude Opus 4.8: 55.2 (#33), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1450 | — |
| LMArena Chinese | 1507 | — |
| LMArena French | 1481 | — |
| LMArena German | 1472 | — |
| LMArena Japanese | 1440 | — |
| LMArena Korean | 1432 | — |
| LMArena Russian | 1474 | — |
| LMArena Spanish | 1466 | — |
Instruction Following Not comparable
Claude Opus 4.8: 77.4 (#24), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1476 | — |
Long Context Not comparable
Claude Opus 4.8: 45.4 (#35), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1483 | — |
Writing & Preference Not comparable
Claude Opus 4.8: 72.0 (#16), Mercury 2.5: —
| Benchmark | Claude Opus 4.8 | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1461 | — |
| LMArena Creative Writing | 1454 | — |
| EQ-Bench Creative Writing | 1840 | — |
| EQ-Bench 4 | 1281 | — |
| LMArena Multi-Turn | 1476 | — |
Frequently asked questions
Is Claude Opus 4.8 better than Mercury 2.5?
Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 33.5 on the Noometry Index. Mercury 2.5 costs 148× less per token, which makes it the better buy when Claude Opus 4.8's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 4.8 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 4.8 lists at $5 and $25.
Is Claude Opus 4.8 or Mercury 2.5 better for coding?
Claude Opus 4.8 scores higher on coding benchmarks: 59.9 versus 39.5 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 4.8 does, with 1M tokens against 260K.
How many benchmarks do Claude Opus 4.8 and Mercury 2.5 share?
4 benchmarks have published results for both models. Claude Opus 4.8 has 65 scored results on Noometry and Mercury 2.5 has 4.