# Devstral Small 2505 vs Mercury 2

> Mercury 2 is the stronger model overall, scoring 39.1 to 34.3 on the Noometry Index. Devstral Small 2505 costs 2.5× less per token, which makes it the better buy when Mercury 2's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/devstral-small-vs-mercury-2
- Last updated: 2026-10-11
- Shared benchmarks: 2

## Summary

- They share 2 benchmarks with published results for both. Devstral Small 2505 scores higher in 1 category and Mercury 2 in 1 category; 2 gaps are clear of the uncertainty.
- The widest gap is in coding, where Devstral Small 2505 leads 38.9 to 33.5.
- The biggest single-benchmark swing is SciCode: 28.8% for Devstral Small 2505 and 38.7% for Mercury 2.
- Devstral Small 2505 is cheaper at $0.10 / $0.30 per million input/output tokens, against $0.25 / $0.75 for Mercury 2.
- Devstral Small 2505 has downloadable open weights; the other is API-only.

## Snapshot

| | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| Provider | Mistral AI | Inception |
| Noometry Index | 34.3 | 39.1 |
| Rank | 233 | 175 |
| Context | 128K | 128K |
| Input $/M | $0.10 | $0.25 |
| Output $/M | $0.30 | $0.75 |
| Weights | Open | Proprietary |

## Coding

- Devstral Small 2505: 38.9 (#166)
- Mercury 2: 33.5 (#255)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| SciCode | 28.8% | 38.7% |
| SWE-bench Verified (bash only) | 56.4% | — |
| LMArena WebDev | — | 1171 |
| WeirdML | — | 43.2% |
| LMArena Coding | — | 1391 |
| ALE-Bench | — | 785.58 |

## Reasoning

- Devstral Small 2505: 19.7 (#252)
- Mercury 2: 23.8 (#170)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| CritPt | 0% | 0.8% |
| Kagi LLM Benchmark | 37.7% | — |
| LMArena Hard Prompts | — | 1362 |

## Knowledge

- Devstral Small 2505: —
- Mercury 2: 36.2 (#172)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| Vectara Hallucination Rate | — | 12.3% |
| LMArena Expert | — | 1358 |

## Multilingual

- Devstral Small 2505: —
- Mercury 2: 46.6 (#157)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| LMArena Non-English | — | 1331 |
| LMArena Chinese | — | 1417 |
| LMArena Russian | — | 1304 |

## Instruction Following

- Devstral Small 2505: —
- Mercury 2: 70.2 (#165)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| LMArena Instruction Following | — | 1329 |

## Long Context

- Devstral Small 2505: —
- Mercury 2: 40.5 (#154)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| LMArena Longer Query | — | 1330 |

## Writing & Preference

- Devstral Small 2505: —
- Mercury 2: 53.8 (#155)

| Benchmark | Devstral Small 2505 | Mercury 2 |
|---|---|---|
| LMArena Text | — | 1355 |
| LMArena Creative Writing | — | 1289 |
| LMArena Multi-Turn | — | 1358 |

## FAQ

### Is Devstral Small 2505 better than Mercury 2?

Mercury 2 is the stronger model overall, scoring 39.1 to 34.3 on the Noometry Index. Devstral Small 2505 costs 2.5× less per token, which makes it the better buy when Mercury 2's lead doesn't matter for your workload.

### Which is cheaper, Devstral Small 2505 or Mercury 2?

Devstral Small 2505 is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Mercury 2 lists at $0.25 and $0.75.

### Is Devstral Small 2505 or Mercury 2 better for coding?

Devstral Small 2505 scores higher on coding benchmarks: 38.9 versus 33.5 in the Noometry coding category.

### Which has the bigger context window?

Both accept 128K tokens.

### How many benchmarks do Devstral Small 2505 and Mercury 2 share?

2 benchmarks have published results for both models. Devstral Small 2505 has 4 scored results on Noometry and Mercury 2 has 17.