ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT OSS 20B vs Mistral Small 3.2

GPT OSS 20B comes out ahead, 64 to 60 on our weighted score, and it is the cheaper option too.

  1. Our pick

    OpenAI

    GPT OSS 20B

    Released Aug 5, 2025

    64/100
    • ECI137.8
    • Price$0.07 / $0.295
    • Context131K
    Full specs Remove GPT OSS 20B

  2. Mistral AI

    Mistral Small 3.2

    Released Jun 20, 2025

    60/100
    • ECI131.7
    • Price$0.10 / $0.30
    • Context128K
    Full specs Remove Mistral Small 3.2

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT OSS 20B is our pick

GPT OSS 20B is the better all-round choice, scoring 64/100 against Mistral Small 3.2 (60). It leads on capability and price. Mistral Small 3.2 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT OSS 20BCapabilities Index (ECI): GPT OSS 20B 137.8 · Mistral Small 3.2 131.7
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.126 · Mistral Small 3.2 $0.15 per 1M tokens (3:1 blend)
  • Longest contextGPT OSS 20BGPT OSS 20B 131,072 · Mistral Small 3.2 128,000 tokens
  • Widest inputsMistral Small 3.2GPT OSS 20B: Text · Mistral Small 3.2: Text, Images
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightGPT OSS 20BMistral Small 3.2
CapabilityCapabilities Index (ECI)50%6355
Price25%9289
Inputs & features15%4550
Context window10%2424
Overall100%64/10060/100
02 — Side by side

Every spec in one table

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

GPT OSS 20B vs Mistral Small 3.2 specifications side by side
SpecificationGPT OSS 20BOpenAIMistral Small 3.2Mistral AI
Capability
Capabilities Index (ECI)137.8 (best)131.7
ECI rank#108 of 148 (best)#123 of 148
GPQA DiamondGraduate-level science questions60.8% (best)49.1%
OTIS Mock AIME 2024–2025Competition mathematics65.3% (best)30.3%
Price per million tokens
Input$0.07 (best)$0.10
Output$0.295 (best)$0.30
Cached input——
Blended (3:1)$0.126 (best)$0.15
Long-context rateSame rateSame rate
Price sourceMedian of 18 providersOfficial Mistral API
Limits
Context window131,072 tokens (best)128,000 tokens
Max output32,768 tokens (best)16,384 tokens
Inputs and features
TextYesYes
ImagesNoYes
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesNo
Tool callingYesYes
Structured outputYesNo
Availability
WeightsOpenOpen
API model ID—mistral-small-2506
API providers19 (best)6
ReleasedAug 5, 2025Jun 20, 2025
Knowledge cutoff—Mar 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.

  • GPT OSS 20B$1.29
  • Mistral Small 3.2$1.60
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or Mistral Small 3.2?

GPT OSS 20B is the better all-round choice, scoring 64/100 against Mistral Small 3.2 (60). It leads on capability and price. Mistral Small 3.2 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 20B or Mistral Small 3.2?

GPT OSS 20B is cheaper at $0.07 input / $0.295 output per million tokens (median across 18 API providers). Mistral Small 3.2 costs $0.10 input / $0.30 output per million tokens (official Mistral API price). At a typical mix of three input tokens to one output token, that is $0.126 per million tokens for GPT OSS 20B versus $0.15 for Mistral Small 3.2 (1.2× as much).

Which scores higher on benchmarks?

GPT OSS 20B scores higher on the Capabilities Index (ECI): GPT OSS 20B 137.8 (#108 of 148) and Mistral Small 3.2 131.7 (#123 of 148). The confidence ranges of the top two overlap (133.0–139.6 vs 126.6–133.9), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT OSS 20B 60.8%, Mistral Small 3.2 49.1%; OTIS Mock AIME 2024–2025 — GPT OSS 20B 65.3%, Mistral Small 3.2 30.3%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and Mistral Small 3.2 yet, so there is no like-for-like coding score. On overall capability, GPT OSS 20B 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?

GPT OSS 20B has the largest context window at 131,072 tokens, against 128,000 for Mistral Small 3.2. Maximum output per response: GPT OSS 20B up to 32,768, Mistral Small 3.2 up to 16,384 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; Mistral Small 3.2 accepts text and images. Mistral Small 3.2 handles the widest range of inputs.

Are any of these open source?

Yes, both publish their weights, so you can self-host them.

Which is newer?

GPT OSS 20B is the newest, released Aug 5, 2025. Mistral Small 3.2 came out Jun 20, 2025. Knowledge cutoff: Mistral Small 3.2 Mar 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.

05 — Keep comparing

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