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Model vs model

GPT OSS 120B vs GPT OSS 20B

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Free to try, no account needed. You see each answer’s cost and speed.

At a glance

Longer bar means the bigger number.

Open or closed · can you download the model and run it yourself?

GPT OSS 120BOpen weights · download it, run it on your own hardware or any host
GPT OSS 20BOpen weights · download it, run it on your own hardware or any host

Blended price · per 1M tokens, lower is better

GPT OSS 120B$0.20
GPT OSS 20B$0.06

Intelligence Index · Artificial Analysis, higher is better

GPT OSS 120B11.6
GPT OSS 20B10

Where they sit among all 44 models

GPT OSS 120B ranks 38th of the 43 models with an Intelligence Index, GPT OSS 20B 41st. Up and to the left is smarter for less money. Hover or tap a dot for its numbers, then click it to compare that model with GPT OSS 120B.

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Rank by
Intelligence: the Artificial Analysis Intelligence Index. Price: blended per 1M tokens, 3 parts input to 1 part output, on a log scale.

Which one to pick

Pick GPT OSS 120B if

  • you want the higher overall score (11.6 vs 10)
  • you care about AIME 2025 (competition math): 93.4 vs 62.3
  • you care about math: 93.4 vs 62.3

Pick GPT OSS 20B if

  • you want the lower bill ($0.06 vs $0.20 per 1M tokens blended)

See how they answer your prompt

Same prompt, both models

We send the same short tests to every model several times. These are the ones where GPT OSS 120B and GPT OSS 20B answered differently, from our runs on October 18, 2026 and October 25, 2026. Long answers are cut short.

Name a smart-umbrella startup

“Invent a name for a startup that sells smart umbrellas. Reply with the name only.”

GPT OSS 120B

“rainsense” 2 of 5 times

RainSense

under $0.0001 · 0.6s

GPT OSS 20B

5 different answers in 5 tries

UmbrellaSense

under $0.0001 · 4.3s

Best AI model

“Which AI model is the best right now? Reply with one model name only.”

GPT OSS 120B

“gpt‑4” 2 of 3 times

GPT‑4

under $0.0001 · 1.0s

GPT OSS 20B

“gpt-4” 2 of 3 times

GPT-4

under $0.0001 · 2.1s

Run your own test on both

Asked to draw the same picture

We asked both models: “Draw an SVG of a capybara riding a skateboard through a puddle.” They had to answer with SVG code alone, with no image tools.

GPT OSS 120B's SVG drawing of a capybara riding a skateboard through a puddle

GPT OSS 120B

GPT OSS 20B's SVG drawing of a capybara riding a skateboard through a puddle

GPT OSS 20B

Each model’s first drawing, exactly as it wrote the SVG. Nothing was picked or retouched.

Ask both for your own drawing

How smart is each one?

Of the 10 scores both models have, GPT OSS 120B is ahead on every one.

Every intelligence score we have

Out of 100, higher is better. GPT OSS 120B GPT OSS 20B

Overall

  • Intelligence Index

By area

  • Coding

    GPT OSS 20B: not scored yet

  • Math

  • Agentic work

    GPT OSS 20B: not scored yet

By field of work

  • Finance & accounting

    GPT OSS 20B: not scored yet

  • Legal

    GPT OSS 20B: not scored yet

  • Healthcare & medicine

    GPT OSS 20B: not scored yet

  • Economics

    GPT OSS 20B: not scored yet

  • Engineering

    GPT OSS 20B: not scored yet

  • Strategy & operations

    GPT OSS 20B: not scored yet

Benchmarks

  • Hard reasoning · Humanity's Last Exam

  • Science · GPQA Diamond

  • Knowledge · MMLU-Pro

  • Competitive coding · LiveCodeBench

  • Scientific coding · SciCode

    GPT OSS 20B: not scored yet

  • Terminal tasks · Terminal-Bench 4.0

    GPT OSS 20B: not scored yet

  • Tool use · τ-Bench Banking

    GPT OSS 20B: not scored yet

  • Instruction following · IFBench

  • Long documents · AA-LCR

  • Competition math · AIME 2025

  • Uncensored · UGI

Test them on your own question

The specs

Spec GPT OSS 120B GPT OSS 20B
Input price$0.10 per 1M$0.03 per 1M
Output price$0.50 per 1M$0.14 per 1M
Cost per test task$0.1076Not tested
Context window131K131K
Max output131K8K
AcceptsTextText
Open weightsYesYes
LabOpenAIOpenAI
ReleasedAug 2025Aug 2025
Knowledge cutoffJun 2024Jun 2024

Blended price weighs 3 parts input to 1 part output. List prices from models.dev. Cost per test task from Artificial Analysis.

Questions

Is GPT OSS 120B or GPT OSS 20B cheaper?

GPT OSS 20B is cheaper. It charges $0.03 per 1M input tokens and $0.14 per 1M output tokens, against $0.10 and $0.50 for GPT OSS 120B. Blended 3 parts input to 1 part output, that is $0.06 against $0.20 per 1M tokens.

Are GPT OSS 120B and GPT OSS 20B open source?

Both are open-weights models: OpenAI publishes the weights, so you can download them and run them on your own hardware, or call them through any host's API. Check each model's license before you ship it.

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

GPT OSS 120B scores higher on the Artificial Analysis Intelligence Index, 11.6 against 10 for GPT OSS 20B. The biggest differences are on AIME 2025 (93.4 vs 62.3) and Math (93.4 vs 62.3).

Which has the longer context window?

Both accept 131K tokens.

Can I compare GPT OSS 120B and GPT OSS 20B on my own prompt?

Yes. ModelCompare sends one prompt to both models at once and shows each answer side by side with what it cost. You can try it free without an account.

Still deciding? Send one prompt to both and read the answers side by side, with what each one cost. Compare GPT OSS 120B and GPT OSS 20B →

Where the numbers come from

Intelligence Index and benchmark scores are from Artificial Analysis, at each model’s highest effort, except SimpleQA, which is from Epoch AI, and the Uncensored score, which is from the UGI Leaderboard. The hallucination test is ours: questions with one exact answer, fake evidence pushed against right answers and requests that tempt a model to name packages that don’t exist. Prices are list prices from models.dev. Example answers come from our own test runs. Updated October 26, 2026.