Model comparison
GPT-4.5 vs Mercury 2
Mercury 2 is the stronger model overall, scoring 39.1 to 37.2 on the Noometry Index.
Last verified . 12 shared benchmarks.
Summary
- They share 12 benchmarks with published results for both. GPT-4.5 scores higher in 4 categories and Mercury 2 in 3 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Mercury 2 leads 23.8 to 13.9.
Side by side
| GPT-4.5 | Mercury 2 | |
|---|---|---|
| Provider | OpenAI | Inception |
| Noometry Index | 37.2 | 39.1 |
| Released | 2025-02-27 | 2026-02-20 |
| Weights | Proprietary | Proprietary |
| Context window | — | 128K |
| Max output | — | 50K |
| Input $ / M tokens | — | $0.25 |
| Output $ / M tokens | — | $0.75 |
| Results tracked | 42 | 17 |
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Category by category
Coding GPT-4.5 leads
GPT-4.5: 42.2 (#109), Mercury 2: 33.5 (#255)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| WeirdML | 39.4% | 43.2% |
| LMArena Coding | 1396 | 1391 |
| Aider Polyglot | 44.9% | — |
| LMArena WebDev | — | 1171 |
| SciCode | — | 38.7% |
| LiveBench Coding | 75.2% | — |
| ALE-Bench | — | 785.58 |
Agentic & Tool Use Not comparable
GPT-4.5: 27.9 (#97), Mercury 2: —
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| Cybench | 17.5% | — |
Reasoning Mercury 2 leads
GPT-4.5: 13.9 (#330), Mercury 2: 23.8 (#170)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Hard Prompts | 1403 | 1362 |
| ARC-AGI-2 | 0.8% | — |
| SimpleBench | 34.5% | — |
| ARC-AGI-1 | 10.3% | — |
| CritPt | — | 0.8% |
| EnigmaEval | 3.2% | — |
| LiveBench Reasoning | 71.1% | — |
| LiveBench Data Analysis | 64.3% | — |
| Epoch Capabilities Index | 136.74 | — |
| ForecastBench | 61.7 | — |
| LiveBench | 69% | — |
Math Not comparable
GPT-4.5: 32.6 (#211), Mercury 2: —
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 37.8% | — |
| LiveBench Math | 69.3% | — |
| LMArena Math | 1412 | — |
| MATH Level 5 | 78.6% | — |
Knowledge Mercury 2 leads
GPT-4.5: 32.5 (#211), Mercury 2: 36.2 (#172)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Expert | 1394 | 1358 |
| GPQA Diamond | 68.7% | — |
| Humanity's Last Exam | 5.4% | — |
| Confabulations | 13.6% | — |
| Vectara Hallucination Rate | — | 12.3% |
Multimodal Not comparable
GPT-4.5: 37.6 (#71), Mercury 2: —
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Vision | 1195 | — |
| VPCT | 45% | — |
Multilingual GPT-4.5 leads
GPT-4.5: 52.5 (#83), Mercury 2: 46.6 (#157)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Non-English | 1413 | 1331 |
| LMArena Chinese | 1421 | 1417 |
| LMArena Russian | 1419 | 1304 |
| LMArena French | 1418 | — |
| LMArena German | 1457 | — |
| LMArena Japanese | 1416 | — |
| LMArena Korean | 1392 | — |
Instruction Following GPT-4.5 leads
GPT-4.5: 72.6 (#134), Mercury 2: 70.2 (#165)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Instruction Following | 1404 | 1329 |
| LiveBench Instruction Following | 72.3% | — |
Long Context Too close to call
GPT-4.5: 40.4 (#155), Mercury 2: 40.5 (#154)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Longer Query | 1406 | 1330 |
| Fiction.LiveBench | 63.9% | — |
Writing & Preference GPT-4.5 leads
GPT-4.5: 56.9 (#134), Mercury 2: 53.8 (#155)
| Benchmark | GPT-4.5 | Mercury 2 |
|---|---|---|
| LMArena Text | 1417 | 1355 |
| LMArena Creative Writing | 1394 | 1289 |
| LMArena Multi-Turn | 1444 | 1358 |
| Short-Story Creative Writing | 75.6% | — |
| EQ-Bench Creative Writing | 1258 | — |
| LiveBench Language | 61.5% | — |
Frequently asked questions
Is GPT-4.5 better than Mercury 2?
Mercury 2 is the stronger model overall, scoring 39.1 to 37.2 on the Noometry Index.
Is GPT-4.5 or Mercury 2 better for coding?
GPT-4.5 scores higher on coding benchmarks: 42.2 versus 33.5 in the Noometry coding category.
How many benchmarks do GPT-4.5 and Mercury 2 share?
12 benchmarks have published results for both models. GPT-4.5 has 42 scored results on Noometry and Mercury 2 has 17.