Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | o3 | Mistral Medium |
|---|---|---|
| Input ($/M tokens) | $2 | $1.5 |
| Output ($/M tokens) | $8 | $7.5 |
Verdict. o3 wins the overall benchmark matchup 1–0 across 1 overlapping categories, but raw benchmark score is only one input to the decision.
Pricing. Both models sit in the mid-tier bracket for output-token pricing. At 1.1× the per-million-token cost, Mistral Medium is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Mistral Medium makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. o3 is strongest on Intelligence Index (20.2). Mistral Medium leads on Intelligence Index (5.5).
Speed. Throughput is comparable — 144 tok/s vs 142 tok/s — so generation speed shouldn't drive your choice here. Look at the per-benchmark wins instead.
Provider. OpenAI and Mistral sell to overlapping but distinct developer audiences: OpenAI tends to ship frontier reasoning models with premium positioning, while Mistral often prices more aggressively. Your existing vendor relationships, billing, and SLA preferences may matter as much as the raw numbers above.
Workload cost. Workload scenarios (per million requests at 30M input + 15M output tokens): o3 costs $180.00 ($2160/year); Mistral Medium costs $157.50 ($1890/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): o3 ≈ $26.00/run, Mistral Medium ≈ $22.50/run. At agent/realtime scale (200M input / 100M output per million requests): o3 ≈ $1200/run, Mistral Medium ≈ $1050/run. Mistral Medium becomes more attractive at higher volume — the absolute per-token pricing difference compounds when you ship at scale.
Recommendation. Both models have legitimate use cases — the right answer depends on whether you are optimizing for benchmark ceiling, latency, or unit cost. Start with the cheaper / faster model, evaluate against your specific task, and only switch if the upgrade shows a meaningful lift.
Data from Artificial Analysis API — 12 benchmarks
Mistral Medium is cheaper overall. Its blended price (3:1 input/output ratio) is $3.00/M tokens vs $3.50/M for o3.
o3 wins 1 out of 12 benchmarks compared to 0 for Mistral Medium. See the detailed benchmark chart above for per-category results.
o3 generates tokens faster at 144 tok/s vs 142 tok/s. However, Mistral Medium has lower time-to-first-token (2.23s vs 4.51s).
Choose based on your priorities: Mistral Medium for lower cost, o3 for stronger benchmark performance, and o3 for faster generation. For latency-sensitive apps, check the TTFT comparison above.