Model comparison
GPT-6.1 Sol vs Mercury 2
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 39.1 on the Noometry Index. Mercury 2 costs 11× less per token, which makes it the better buy when GPT-6.1 Sol's lead doesn't matter for your workload.
Last verified . 14 shared benchmarks.
Summary
- They share 14 benchmarks with published results for both. GPT-6.1 Sol scores higher in 7 categories and Mercury 2 in 0 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-6.1 Sol leads 81.9 to 23.8.
- The biggest single-benchmark swing is CritPt: 31.7% for GPT-6.1 Sol and 0.8% for Mercury 2.
- Mercury 2 is cheaper at $0.25 / $0.75 per million input/output tokens, against $2 / $10 for GPT-6.1 Sol.
- GPT-6.1 Sol accepts more context: 1.05M tokens versus 128K.
Side by side
| GPT-6.1 Sol | Mercury 2 | |
|---|---|---|
| Provider | OpenAI | Inception |
| Noometry Index | 65.6 | 39.1 |
| Released | 2026-09-29 | 2026-02-20 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 128K |
| Max output | 128K | 50K |
| Input $ / M tokens | $2 | $0.25 |
| Output $ / M tokens | $10 | $0.75 |
| Results tracked | 34 | 17 |
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Category by category
Coding GPT-6.1 Sol leads
GPT-6.1 Sol: 63.2 (#8), Mercury 2: 33.5 (#255)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena WebDev | 1755 | 1171 |
| SciCode | 55.8% | 38.7% |
| LMArena Coding | 1487 | 1391 |
| DeepSWE | 75.2% | — |
| FrontierCode | 50.2% | — |
| WeirdML | — | 43.2% |
| ALE-Bench | — | 785.58 |
Agentic & Tool Use Not comparable
GPT-6.1 Sol: 39.6 (#26), Mercury 2: —
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| APEX-Agents | 60% | — |
| GDP.pdf | 32% | — |
Reasoning GPT-6.1 Sol leads
GPT-6.1 Sol: 81.9 (#2), Mercury 2: 23.8 (#170)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| CritPt | 31.7% | 0.8% |
| LMArena Hard Prompts | 1466 | 1362 |
| ARC-AGI-2 | 94.2% | — |
| NYT Connections (extended) | 95.5% | — |
| ARC-AGI-1 | 98.5% | — |
| Chess Puzzles | 61% | — |
| EBR-Bench | 54.3% | — |
| Mystery Game Puzzles | 80% | — |
| Epoch Capabilities Index | 166.09 | — |
Math Not comparable
GPT-6.1 Sol: 93.7 (#1), Mercury 2: —
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 93.7% | — |
| FrontierMath Tier 4 | 100% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 99% | — |
| LMArena Math | 1464 | — |
Knowledge GPT-6.1 Sol leads
GPT-6.1 Sol: 71.8 (#4), Mercury 2: 36.2 (#172)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Expert | 1502 | 1358 |
| GPQA Diamond | 95.4% | — |
| SimpleQA Verified | 73.9% | — |
| Vectara Hallucination Rate | — | 12.3% |
Multimodal Not comparable
GPT-6.1 Sol: 52.7 (#5), Mercury 2: —
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Vision | 1288 | — |
| Furniture Assembly | 80% | — |
Multilingual GPT-6.1 Sol leads
GPT-6.1 Sol: 54.3 (#46), Mercury 2: 46.6 (#157)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Non-English | 1438 | 1331 |
| LMArena Chinese | 1477 | 1417 |
| LMArena Russian | 1455 | 1304 |
Instruction Following GPT-6.1 Sol leads
GPT-6.1 Sol: 77.0 (#29), Mercury 2: 70.2 (#165)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Instruction Following | 1468 | 1329 |
Long Context GPT-6.1 Sol leads
GPT-6.1 Sol: 44.9 (#54), Mercury 2: 40.5 (#154)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Longer Query | 1465 | 1330 |
Writing & Preference GPT-6.1 Sol leads
GPT-6.1 Sol: 63.6 (#63), Mercury 2: 53.8 (#155)
| Benchmark | GPT-6.1 Sol | Mercury 2 |
|---|---|---|
| LMArena Text | 1447 | 1355 |
| LMArena Creative Writing | 1432 | 1289 |
| LMArena Multi-Turn | 1449 | 1358 |
Frequently asked questions
Is GPT-6.1 Sol better than Mercury 2?
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 39.1 on the Noometry Index. Mercury 2 costs 11× less per token, which makes it the better buy when GPT-6.1 Sol's lead doesn't matter for your workload.
Which is cheaper, GPT-6.1 Sol or Mercury 2?
Mercury 2 is cheaper. It lists at $0.25 per million input tokens and $0.75 per million output tokens; GPT-6.1 Sol lists at $2 and $10.
Is GPT-6.1 Sol or Mercury 2 better for coding?
GPT-6.1 Sol scores higher on coding benchmarks: 63.2 versus 33.5 in the Noometry coding category.
Which has the bigger context window?
GPT-6.1 Sol does, with 1.05M tokens against 128K.
How many benchmarks do GPT-6.1 Sol and Mercury 2 share?
14 benchmarks have published results for both models. GPT-6.1 Sol has 34 scored results on Noometry and Mercury 2 has 17.