Mistral Medium 3.5 Open vs 
o3 Paid
Mistral Medium 3.5 vs o3 compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
Mistral Medium 3.5 vs o3 specs
| Spec | Mistral Medium 3.5 | o3 |
|---|---|---|
| Maker | Mistral AI | OpenAI |
| Type | Open-weight | Proprietary |
| Context window | 262K tokens | 200K tokens |
| Input price | $1.5/M · free self-host | $2/M |
| Output price | $7.5/M · free self-host | $8/M |
| Vision / multimodal | Yes | Yes |
| Tool / function calling | Yes | Yes |
| Self-hostable | Yes | No (API only) |
| License | Apache 2.0 | Proprietary |
Feature comparison
| Capability | Mistral Medium 3.5 | o3 |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✓ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✗ | ✗ |
Benchmarks: Mistral Medium 3.5 vs o3
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Mistral Medium 3.5 and o3 score
| Criterion | Mistral Medium 3.5 | o3 |
|---|---|---|
| Cost-efficiency | 4.0 | 3.5 |
| Context window | 4.0 | 4.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 5.0 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Mistral Medium 3.5 Open
Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...
o3 Paid
o3 is a well-rounded and powerful model across domains. It sets a new standard for math, science, coding, and visual reasoning tasks. It also excels at technical writing and instruction-following....
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is Mistral Medium 3.5 as good as o3?
Mistral Medium 3.5 is open-weight and competitive on many tasks, but o3 may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run Mistral Medium 3.5 locally?
Yes. Mistral Medium 3.5 has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. o3 is API-only and cannot be self-hosted.
Mistral Medium 3.5 vs o3 — which should I pick in 2026?
Choose Mistral Medium 3.5 if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose o3 if you want frontier capability through a managed API with zero infrastructure to run.
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