Model comparison
GPT-5.3 Codex vs Mistral Medium 3.5
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 40.2 on the Noometry Index. Mistral Medium 3.5 costs 1.6× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
Mistral AISummary
- They share 2 benchmarks with published results for both. GPT-5.3 Codex scores higher in 1 category and Mistral Medium 3.5 in 0 categories; one gap is clear of the uncertainty.
- The widest gap is in coding, where GPT-5.3 Codex leads 48.6 to 36.0.
- Mistral Medium 3.5 is cheaper at $1.50 / $7.50 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- GPT-5.3 Codex accepts more context: 400K tokens versus 262K.
- Mistral Medium 3.5 has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Mistral Medium 3.5 | |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Noometry Index | 45.8 | 40.2 |
| Released | 2026-02-05 | — |
| Weights | Proprietary | Open |
| Context window | 400K | 262K |
| Max output | 128K | 210K |
| Input $ / M tokens | $1.75 | $1.50 |
| Output $ / M tokens | $14 | $7.50 |
| Results tracked | 8 | 22 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), Mistral Medium 3.5: 36.0 (#213)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena WebDev | 1409 | 1264 |
| SWE-bench Verified | 74.8% | — |
| WeirdML | 79.3% | — |
| LMArena Coding | — | 1461 |
| ALE-Bench | 1,655 | — |
Agentic & Tool Use Not comparable
GPT-5.3 Codex: 48.0 (#9), Mistral Medium 3.5: —
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| Terminal-Bench | 78.4% | — |
| METR Time Horizons | 74.5% | — |
| Vending-Bench 2 | 5,940 | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 17.3 (#295)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| Epoch Capabilities Index | 156.77 | 141.35 |
| Kagi LLM Benchmark | — | 41.4% |
| NYT Connections (extended) | — | 12.9% |
| LMArena Hard Prompts | — | 1436 |
Math Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 39.1 (#113)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Math | — | 1431 |
Knowledge Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 40.0 (#126)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Expert | — | 1432 |
Multimodal Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 38.3 (#65)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Vision | — | 1223 |
Multilingual Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 51.9 (#100)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Non-English | — | 1404 |
| LMArena Chinese | — | 1442 |
| LMArena French | — | 1448 |
| LMArena German | — | 1451 |
| LMArena Korean | — | 1385 |
| LMArena Russian | — | 1395 |
| LMArena Spanish | — | 1409 |
Instruction Following Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 74.6 (#90)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Instruction Following | — | 1415 |
Long Context Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 43.2 (#103)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Longer Query | — | 1415 |
Writing & Preference Not comparable
GPT-5.3 Codex: —, Mistral Medium 3.5: 58.5 (#117)
| Benchmark | GPT-5.3 Codex | Mistral Medium 3.5 |
|---|---|---|
| LMArena Text | — | 1421 |
| LMArena Creative Writing | — | 1374 |
| EQ-Bench 4 | — | 993 |
| LMArena Multi-Turn | — | 1423 |
Frequently asked questions
Is GPT-5.3 Codex better than Mistral Medium 3.5?
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 40.2 on the Noometry Index. Mistral Medium 3.5 costs 1.6× 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, GPT-5.3 Codex or Mistral Medium 3.5?
Mistral Medium 3.5 is cheaper. It lists at $1.50 per million input tokens and $7.50 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.
Is GPT-5.3 Codex or Mistral Medium 3.5 better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 36.0 in the Noometry coding category.
Which has the bigger context window?
GPT-5.3 Codex does, with 400K tokens against 262K.
How many benchmarks do GPT-5.3 Codex and Mistral Medium 3.5 share?
2 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Mistral Medium 3.5 has 22.