# Mistral Medium 3.5 128B vs o3

> Side-by-side benchmark comparison for Mistral Medium 3.5 128B and o3 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/mistral-medium-3-5-128b-vs-o3
- Last updated: September 10, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for Mistral Medium 3.5 128B and o3.

## Summary

- Mistral Medium 3.5 128B and o3 do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | Mistral Medium 3.5 128B | o3 |
|----------|----------|----------|
| Creator | Mistral | OpenAI |
| Type | Open Weight | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 256K | 200K |
| Independent public score (not head-to-head) | 30.13 | 47.55 |
| Benchmarks Covered | 7 | 2 |
| Pricing (input/output) | $1.50 / $7.50 | $2.00 / $8.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 21.9 (Supported · #150/152)
- o3 public-lane score: Coming soon

| Benchmark | Mistral Medium 3.5 128B | o3 | Winner |
|-----------|-----------|-----------|--------|
| τ³-bench results | 91.4% | Coming soon | Coming soon |
| Gert Labs | 39.10% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 39.0% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 36.9 (Estimated · #127/151)
- o3 public-lane score: Coming soon

| Benchmark | Mistral Medium 3.5 128B | o3 | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 77.6% | Coming soon | Coming soon |
| SWE-bench (Vals) | 66.4% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 55.6 (Unranked · 1 rankable row)
- o3 public-lane score: 63.3 (Unranked · 1 rankable row)

### Reasoning

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 68.6 (Unranked · 2 rankable rows)
- o3 public-lane score: 72.3 (Unranked · 2 rankable rows)

### Knowledge

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 39 (Supported · #140/183)
- o3 public-lane score: 49 (Estimated · #87/183)

| Benchmark | Mistral Medium 3.5 128B | o3 | Winner |
|-----------|-----------|-----------|--------|
| GPQA Diamond (Vals) | 34.8% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 75.3% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: 84 (#48/123)
- o3 public-lane score: 87.4 (#33/123)

### Mathematics

- Winner: Insufficient shared evidence
- Mistral Medium 3.5 128B public-lane score: Coming soon
- o3 public-lane score: 37.8 (Unranked · 2 rankable rows)

| Benchmark | Mistral Medium 3.5 128B | o3 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | Coming soon | 18.685% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 2.083% | Coming soon |

## FAQ

### Can I compare Mistral Medium 3.5 128B and o3 on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [Mistral Medium 3.5 128B vs o3-pro](/compare/mistral-medium-3-5-128b-vs-o3-pro)
- [o3 vs o3-pro](/compare/o3-vs-o3-pro)
- [Mistral Medium 3.5 128B vs o3-mini](/compare/mistral-medium-3-5-128b-vs-o3-mini)
- [o3 vs o3-mini](/compare/o3-vs-o3-mini)

## Explore More

- [Mistral Medium 3.5 128B profile](/models/mistral-medium-3-5-128b)
- [o3 profile](/models/o3)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)