Model comparison
Devstral Small 2505 vs Step 5 Preview
Step 5 Preview is the stronger model overall, scoring 43.8 to 33.9 on the Noometry Index. Devstral Small 2505 costs 9.5× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Mistral AI
StepFunSummary
- They share 2 benchmarks with published results for both. Devstral Small 2505 scores higher in 0 categories and Step 5 Preview in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 38.0 to 19.1.
- The biggest single-benchmark swing is SciCode: 28.8% for Devstral Small 2505 and 58.9% for Step 5 Preview.
- Devstral Small 2505 is cheaper at $0.10 / $0.30 per million input/output tokens, against $1 / $2.70 for Step 5 Preview.
- Step 5 Preview accepts more context: 1.02M tokens versus 128K.
- Devstral Small 2505 has downloadable open weights; the other is API-only.
Side by side
| Devstral Small 2505 | Step 5 Preview | |
|---|---|---|
| Provider | Mistral AI | StepFun |
| Noometry Index | 33.9 | 43.8 |
| Released | 2025-05-07 | 2026-09-16 |
| Weights | Open | Proprietary |
| Context window | 128K | 1.02M |
| Max output | 128K | 66K |
| Input $ / M tokens | $0.10 | $1 |
| Output $ / M tokens | $0.30 | $2.70 |
| Results tracked | 4 | 3 |
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Category by category
Coding Step 5 Preview leads
Devstral Small 2505: 38.6 (#160), Step 5 Preview: 50.6 (#40)
| Benchmark | Devstral Small 2505 | Step 5 Preview |
|---|---|---|
| SciCode | 28.8% | 58.9% |
| SWE-bench Verified (bash only) | 56.4% | — |
| LMArena WebDev | — | 1569 |
Reasoning Step 5 Preview leads
Devstral Small 2505: 19.1 (#243), Step 5 Preview: 38.0 (#58)
| Benchmark | Devstral Small 2505 | Step 5 Preview |
|---|---|---|
| CritPt | 0% | 20.9% |
| Kagi LLM Benchmark | 37.7% | — |
Frequently asked questions
Is Devstral Small 2505 better than Step 5 Preview?
Step 5 Preview is the stronger model overall, scoring 43.8 to 33.9 on the Noometry Index. Devstral Small 2505 costs 9.5× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.
Which is cheaper, Devstral Small 2505 or Step 5 Preview?
Devstral Small 2505 is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; Step 5 Preview lists at $1 and $2.70.
Is Devstral Small 2505 or Step 5 Preview better for coding?
Step 5 Preview scores higher on coding benchmarks: 50.6 versus 38.6 in the Noometry coding category.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 128K.
How many benchmarks do Devstral Small 2505 and Step 5 Preview share?
2 benchmarks have published results for both models. Devstral Small 2505 has 4 scored results on Noometry and Step 5 Preview has 3.