ZMIME
Comparison · 2 models · Updated Oct 4, 2026

GPT OSS 20B vs GPT OSS 120B

Too close to call on our weighted score (GPT OSS 20B 64, GPT OSS 120B 61). The right pick depends on what you value most.

  1. 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. OpenAI

    GPT OSS 120B

    Released Aug 5, 2025

    61/100
    • ECI140.0
    • Price$0.15 / $0.60
    • Context131K
    Full specs Remove GPT OSS 120B

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01 — Verdict

Too close to call

It is close. Our weighted score puts them within 2 points (GPT OSS 20B 64/100, GPT OSS 120B 61/100), so choose by what matters most for your work: GPT OSS 120B for raw capability and GPT OSS 20B on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT OSS 120BCapabilities Index (ECI): GPT OSS 120B 140.0 · GPT OSS 20B 137.8
  • Lowest priceGPT OSS 20BGPT OSS 20B $0.126 · GPT OSS 120B $0.263 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT OSS 20B 131,072 · GPT OSS 120B 131,072 tokens
  • Widest inputsSame inputsGPT OSS 20B: Text · GPT OSS 120B: Text
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightGPT OSS 20BGPT OSS 120B
CapabilityCapabilities Index (ECI)50%6365
Price25%9277
Inputs & features15%4545
Context window10%2424
Overall100%64/10061/100
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 GPT OSS 120B specifications side by side
SpecificationGPT OSS 20BOpenAIGPT OSS 120BOpenAI
Capability
Capabilities Index (ECI)137.8140.0 (best)
ECI rank#108 of 148#99 of 148 (best)
GPQA DiamondGraduate-level science questions60.8%75.8% (best)
OTIS Mock AIME 2024–2025Competition mathematics65.3%88.9% (best)
Price per million tokens
Input$0.07 (best)$0.15
Output$0.295 (best)$0.60
Cached input——
Blended (3:1)$0.126 (best)$0.263
Long-context rateSame rateSame rate
Price sourceMedian of 18 providersMedian of 36 providers
Limits
Context window131,072 tokens131,072 tokens
Max output32,768 tokens32,768 tokens
Inputs and features
TextYesYes
ImagesNoNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYesYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsOpenOpen
API model ID——
API providers1939 (best)
ReleasedAug 5, 2025Aug 5, 2025
Knowledge cutoff——
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
  • GPT OSS 120B$2.70
04 — Questions

Which should you choose?

Which is better: GPT OSS 20B or GPT OSS 120B?

It is close. Our weighted score puts them within 2 points (GPT OSS 20B 64/100, GPT OSS 120B 61/100), so choose by what matters most for your work: GPT OSS 120B for raw capability and GPT OSS 20B on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT OSS 20B or GPT OSS 120B?

GPT OSS 20B is cheaper at $0.07 input / $0.295 output per million tokens (median across 18 API providers). GPT OSS 120B costs $0.15 input / $0.60 output per million tokens (median across 36 API providers). At a typical mix of three input tokens to one output token, that is $0.126 per million tokens for GPT OSS 20B versus $0.263 for GPT OSS 120B (2.1× as much).

Which scores higher on benchmarks?

GPT OSS 120B scores higher on the Capabilities Index (ECI): GPT OSS 120B 140.0 (#99 of 148) and GPT OSS 20B 137.8 (#108 of 148). The confidence ranges of the top two overlap (135.3–142.3 vs 133.0–139.6), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT OSS 120B 75.8%, GPT OSS 20B 60.8%; OTIS Mock AIME 2024–2025 — GPT OSS 120B 88.9%, GPT OSS 20B 65.3%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT OSS 20B and GPT OSS 120B yet, so there is no like-for-like coding score. On overall capability, GPT OSS 120B 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 and GPT OSS 120B share the same 131,072-token context window. Maximum output per response: GPT OSS 20B up to 32,768, GPT OSS 120B up to 32,768 tokens.

Which can read images, PDFs, audio or video?

GPT OSS 20B accepts text; GPT OSS 120B accepts text. They handle the same number of input types.

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. GPT OSS 120B came out Aug 5, 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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