ZMIME
Comparison · 2 models · Updated Oct 4, 2026

o3-pro vs Mistral Medium 3

Too close to call on our weighted score (Mistral Medium 3 53, o3-pro 51). The right pick depends on what you value most.

  1. OpenAI

    o3-pro

    Released Jun 10, 2025

    51/100
    • ECI147.4
    • Price$20.00 / $80.00
    • Context200K
  2. Mistral AI

    Mistral Medium 3

    Released May 7, 2025

    53/100
    • ECI134.1
    • Price$0.40 / $2.00
    • Context131K
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01 — Verdict

Too close to call

It is close. Our weighted score puts them within 1 points (Mistral Medium 3 53/100, o3-pro 51/100), so choose by what matters most for your work: o3-pro for raw capability and Mistral Medium 3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • Capabilityo3-proCapabilities Index (ECI): o3-pro 147.4 · Mistral Medium 3 134.1
  • Lowest priceMistral Medium 3Mistral Medium 3 $0.80 · o3-pro $35.00 per 1M tokens (3:1 blend)
  • Longest contexto3-proo3-pro 200,000 · Mistral Medium 3 131,072 tokens
  • Widest inputsSame inputso3-pro: Text, Images · Mistral Medium 3: Text, Images
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeighto3-proMistral Medium 3
CapabilityCapabilities Index (ECI)50%7558
Price25%054
Inputs & features15%7050
Context window10%3224
Overall100%51/10053/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

o3-pro vs Mistral Medium 3 specifications side by side
Specificationo3-proOpenAIMistral Medium 3Mistral AI
Capability
Capabilities Index (ECI)147.4 (best)134.1
ECI rank#60 of 148 (best)#117 of 148
GPQA DiamondGraduate-level science questions—59.5%
OTIS Mock AIME 2024–2025Competition mathematics—32.2%
Price per million tokens
Input$20.00$0.40 (best)
Output$80.00$2.00 (best)
Cached input——
Blended (3:1)$35.00$0.80 (best)
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIOfficial Mistral API
Limits
Context window200,000 tokens (best)131,072 tokens
Max output100,000 tokens131,072 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · highNo
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryProprietary
API model IDo3-promistral-medium-2505
API providers6 (best)5
ReleasedJun 10, 2025May 7, 2025
Knowledge cutoffMay 2024May 2025
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • o3-pro$360.00
  • Mistral Medium 3$8.00
04 — Questions

Which should you choose?

Which is better: o3-pro or Mistral Medium 3?

It is close. Our weighted score puts them within 1 points (Mistral Medium 3 53/100, o3-pro 51/100), so choose by what matters most for your work: o3-pro for raw capability and Mistral Medium 3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, o3-pro or Mistral Medium 3?

Mistral Medium 3 is cheaper at $0.40 input / $2.00 output per million tokens (official Mistral API price). o3-pro costs $20.00 input / $80.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $0.80 per million tokens for Mistral Medium 3 versus $35.00 for o3-pro (44× as much).

Which scores higher on benchmarks?

o3-pro scores higher on the Capabilities Index (ECI): o3-pro 147.4 (#60 of 148) and Mistral Medium 3 134.1 (#117 of 148). Their confidence ranges do not overlap (145.8–149.7 vs 130.5–135.6), so the gap is a real one.

Which is better for coding?

There are no published SWE-bench Verified results for o3-pro and Mistral Medium 3 yet, so there is no like-for-like coding score. On overall capability, o3-pro leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

o3-pro has the largest context window at 200,000 tokens, against 131,072 for Mistral Medium 3. Maximum output per response: o3-pro up to 100,000, Mistral Medium 3 up to 131,072 tokens.

Which can read images, PDFs, audio or video?

o3-pro accepts text and images; Mistral Medium 3 accepts text and images. They handle the same number of input types.

Are any of these open source?

No. o3-pro and Mistral Medium 3 are proprietary and only available through APIs and apps.

Which is newer?

o3-pro is the newest, released Jun 10, 2025. Mistral Medium 3 came out May 7, 2025. Knowledge cutoff: o3-pro May 2024, Mistral Medium 3 May 2025.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.