Mistral: Mistral Medium 3.5 vs OpenAI: GPT-5.3-Codex
Side-by-side comparison of specs, pricing, benchmark scores, and task rankings. Updated 2026-11-07.
| Mistral: Mistral Medium 3.5 | OpenAI: GPT-5.3-Codex | |
|---|---|---|
| Vendor | mistralai | openai |
| Quality Score | 100 | 100 |
| Benchmark Score | 53.0 | 73.4 |
| Input Price | $1.50/M | $1.75/M |
| Output Price | $7.50/M | $14.00/M |
| Context Window | 262,144 | 400,000 |
| Max Output | 209,715 | 128,000 |
| Tool Calling | ✓ | ✓ |
| Structured Output | ✓ | ✓ |
| Reasoning Mode | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio | - | - |
| Benchmark Scores | ||
| ai_index | 49.4 | 73.0 |
| ai_index_agentic | 31.3 | - |
| ai_index_coding | 77.4 | - |
The verdict
For a sample job of 1 million input tokens and 250,000 output tokens, Mistral Medium 3.5 costs $3.38 and GPT-5.3-Codex costs $5.25, so Mistral Medium 3.5 is about 1.6 times cheaper for the same work.
GPT-5.3-Codex reads up to 400,000 tokens at once, roughly 600 pages of text, against about 393 pages for Mistral Medium 3.5.
On our blended benchmark score GPT-5.3-Codex leads 73.4 to 53.0.
Across the 19 tasks where they differ, Mistral Medium 3.5 scores higher on 15 (SQL Generation, Code Review, Bug Fixing and others), GPT-5.3-Codex on 4 (Code Completion, Code Refactoring, Code Documentation and others).
Mistral Medium 3.5 was released in April 2026 and GPT-5.3-Codex in February 2026.
Pick Mistral Medium 3.5 if you need lower cost or the stronger all-round task scores; pick GPT-5.3-Codex if you need long documents or benchmark performance.
Costs use current list prices per million tokens; page counts assume about 0.75 words per token and 500 words per page.
Who wins by task?
| Task | Mistral: Mistral Medium 3.5 | OpenAI: GPT-5.3-Codex |
|---|---|---|
| SQL Generation | 153 | 141 |
| Code Review | 147 | 145 |
| Code Completion | 116 | 118 |
| Code Refactoring | 144 | 147 |
| Bug Fixing | 155 | 149 |
| Unit Test Generation | 140 | 132 |
| Code Documentation | 131 | 135 |
| Regex Writing | 128 | 124 |
| CI/CD Pipelines | 132 | 128 |
| Frontend Component Design | 137 | 130 |
| Data Analysis | 151 | 134 |
| CSV / Spreadsheet Cleanup | 142 | 135 |
| ETL Scripting | 138 | 138 |
| JSON Extraction | 134 | 120 |
| Bulk Data Labeling | 123 | 117 |
| OCR / Document Parsing | 139 | 134 |
| Table Extraction from PDFs | 139 | 134 |
| Long-Document Summarization | 141 | 148 |
| Short-Form Summarization | 119 | 116 |
Scores reflect capability match + benchmark data + pricing for each task. Methodology →