# GPT-6.1 Sol vs Mercury 2.5

> GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 33.5 on the Noometry Index. Mercury 2.5 costs 59× less per token, which makes it the better buy when GPT-6.1 Sol's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gpt-6-1-sol-vs-mercury-2-5
- Last updated: 2026-10-12
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. GPT-6.1 Sol 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 GPT-6.1 Sol leads 93.7 to 23.3.
- The biggest single-benchmark swing is ProofBench: 99% for GPT-6.1 Sol and 3% for Mercury 2.5.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $2 / $10 for GPT-6.1 Sol.
- GPT-6.1 Sol accepts more context: 1.05M tokens versus 260K.

## Snapshot

| | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| Provider | OpenAI | Inception |
| Noometry Index | 65.6 | 33.5 |
| Rank | 6 | 242 |
| Context | 1.05M | 260K |
| Input $/M | $2 | $0.04 |
| Output $/M | $10 | $0.15 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-6.1 Sol: 63.2 (#8)
- Mercury 2.5: 39.5 (#156)

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| SciCode | 55.8% | 38.5% |
| DeepSWE | 75.2% | — |
| FrontierCode | 50.2% | — |
| LMArena WebDev | 1755 | — |
| LMArena Coding | 1487 | — |
| ALE-Bench | — | 301.65 |

## Agentic & Tool Use

- GPT-6.1 Sol: 39.6 (#26)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| APEX-Agents | 60% | — |
| GDP.pdf | 32% | — |

## Reasoning

- GPT-6.1 Sol: 81.9 (#2)
- Mercury 2.5: 22.4 (#193)

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| CritPt | 31.7% | 0% |
| ARC-AGI-2 | 94.2% | — |
| NYT Connections (extended) | 95.5% | — |
| ARC-AGI-1 | 98.5% | — |
| Chess Puzzles | 61% | — |
| EBR-Bench | 54.3% | — |
| LMArena Hard Prompts | 1466 | — |
| Mystery Game Puzzles | 80% | — |
| Epoch Capabilities Index | 166.09 | — |

## Math

- GPT-6.1 Sol: 93.7 (#1)
- Mercury 2.5: 23.3 (#272)

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| ProofBench | 99% | 3% |
| FrontierMath (Tiers 1-3) | 93.7% | — |
| FrontierMath Tier 4 | 100% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| LMArena Math | 1464 | — |

## Knowledge

- GPT-6.1 Sol: 71.8 (#4)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| GPQA Diamond | 95.4% | — |
| SimpleQA Verified | 73.9% | — |
| LMArena Expert | 1502 | — |

## Multimodal

- GPT-6.1 Sol: 52.7 (#5)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| LMArena Vision | 1288 | — |
| Furniture Assembly | 80% | — |

## Multilingual

- GPT-6.1 Sol: 54.3 (#46)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| LMArena Non-English | 1438 | — |
| LMArena Chinese | 1477 | — |
| LMArena Russian | 1455 | — |

## Instruction Following

- GPT-6.1 Sol: 77.0 (#29)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| LMArena Instruction Following | 1468 | — |

## Long Context

- GPT-6.1 Sol: 44.9 (#54)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| LMArena Longer Query | 1465 | — |

## Writing & Preference

- GPT-6.1 Sol: 63.6 (#63)
- Mercury 2.5: —

| Benchmark | GPT-6.1 Sol | Mercury 2.5 |
|---|---|---|
| LMArena Text | 1447 | — |
| LMArena Creative Writing | 1432 | — |
| LMArena Multi-Turn | 1449 | — |

## FAQ

### Is GPT-6.1 Sol better than Mercury 2.5?

GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 33.5 on the Noometry Index. Mercury 2.5 costs 59× 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 2.5?

Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; GPT-6.1 Sol lists at $2 and $10.

### Is GPT-6.1 Sol or Mercury 2.5 better for coding?

GPT-6.1 Sol scores higher on coding benchmarks: 63.2 versus 39.5 in the Noometry coding category.

### Which has the bigger context window?

GPT-6.1 Sol does, with 1.05M tokens against 260K.

### How many benchmarks do GPT-6.1 Sol and Mercury 2.5 share?

3 benchmarks have published results for both models. GPT-6.1 Sol has 34 scored results on Noometry and Mercury 2.5 has 4.