# Devstral Small 2505 vs GPT-5.3 Codex

> GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 34.3 on the Noometry Index. Devstral Small 2505 costs 32× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/devstral-small-vs-gpt-5-3-codex
- Last updated: 2026-10-11
- Shared benchmarks: 0

## Summary

- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 38.9.
- Devstral Small 2505 is cheaper at $0.10 / $0.30 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- GPT-5.3 Codex accepts more context: 400K tokens versus 128K.
- Devstral Small 2505 has downloadable open weights; the other is API-only.

## Snapshot

| | Devstral Small 2505 | GPT-5.3 Codex |
|---|---|---|
| Provider | Mistral AI | OpenAI |
| Noometry Index | 34.3 | 45.8 |
| Rank | 233 | 69 |
| Context | 128K | 400K |
| Input $/M | $0.10 | $1.75 |
| Output $/M | $0.30 | $14 |
| Weights | Open | Proprietary |

## Coding

- Devstral Small 2505: 38.9 (#166)
- GPT-5.3 Codex: 48.6 (#56)

| Benchmark | Devstral Small 2505 | GPT-5.3 Codex |
|---|---|---|
| SWE-bench Verified | — | 74.8% |
| SWE-bench Verified (bash only) | 56.4% | — |
| LMArena WebDev | — | 1409 |
| SciCode | 28.8% | — |
| WeirdML | — | 79.3% |
| ALE-Bench | — | 1,655 |

## Agentic & Tool Use

- Devstral Small 2505: —
- GPT-5.3 Codex: 48.0 (#9)

| Benchmark | Devstral Small 2505 | GPT-5.3 Codex |
|---|---|---|
| Terminal-Bench | — | 78.4% |
| METR Time Horizons | — | 74.5% |
| Vending-Bench 2 | — | 5,940 |

## Reasoning

- Devstral Small 2505: 19.7 (#252)
- GPT-5.3 Codex: —

| Benchmark | Devstral Small 2505 | GPT-5.3 Codex |
|---|---|---|
| Kagi LLM Benchmark | 37.7% | — |
| CritPt | 0% | — |
| Epoch Capabilities Index | — | 156.77 |

## FAQ

### Is Devstral Small 2505 better than GPT-5.3 Codex?

GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 34.3 on the Noometry Index. Devstral Small 2505 costs 32× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.

### Which is cheaper, Devstral Small 2505 or GPT-5.3 Codex?

Devstral Small 2505 is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.

### Is Devstral Small 2505 or GPT-5.3 Codex better for coding?

GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 38.9 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.3 Codex does, with 400K tokens against 128K.

### How many benchmarks do Devstral Small 2505 and GPT-5.3 Codex share?

0 benchmarks have published results for both models. Devstral Small 2505 has 4 scored results on Noometry and GPT-5.3 Codex has 8.