gpt-oss-20b

openai/gpt-oss-20b

This model processes text and generates text. It has a context length of 131,072 tokens and supports tool use and reasoning capabilities. It is an open-weight model, with input priced at $0.018 per million tokens and output at $0.09 per million tokens.

  • tool use
  • structured outputs
  • reasoning
  • open-weight

At a glance

provideropenai
releasedJan 1, 1970
context131K
input / M$0.018

Specifications

What the API gives you

Context window
131K tokens
Max output
33K tokens
Input price
$0.018 / 1M tokens
Output price
$0.090 / 1M tokens
Cache read
$0.009 / 1M tokens
Modalities
text → text
Knowledge cutoff
Jun 30, 2024
Released
Jan 1, 1970

Measured evidence

Public benchmark record

Design Arena Website
854 Elo2026-10-20
GPQA Diamond (Epoch AI)‡
60.8% ± 2.52026-08-27medium effort, evaluated 2026-08-27
GPQA Diamond (Epoch AI)‡
46% ± 3.62026-08-06high effort, evaluated 2026-08-06
LMArena Creative Writing
1201 Elo2026-10-15
LMArena Instruction Following
1236 Elo2026-10-15
LMArena Long Query
1250 Elo2026-10-15
LMArena Math
1317 Elo2026-10-15
LMArena Text
1317 Elo2026-10-15
OTIS Mock AIME (Epoch AI)‡
50.8% ± 6.72026-08-27high effort, evaluated 2026-08-27

LMArena data licensed CC-BY-4.0. Aider (Apache-2.0) and SWE-bench (MIT) are open. Design Arena uses blind human preference. ‡ Submitted scaffold plus model result. Compare the harness and effort settings, not only the model name.

Open-weight model on Hugging Face.

Task evidence

How broad is the support?

Each status is exact to this model version and the selected task. Official release claims remain provisional.

  • Best LLM for Logic & Problem SolvingEstablished evidence

    55% of intended weighted task evidence across 2 independent sources. 5 of 5 configured evaluation feeds currently have results.

  • Best LLM for Math & ReasoningEstablished evidence

    44% of intended weighted task evidence across 3 independent sources. 7 of 7 configured evaluation feeds currently have results.

  • Best LLM for Competition MathEstablished evidence

    37% of intended weighted task evidence across 2 independent sources. 6 of 6 configured evaluation feeds currently have results.

  • Best LLM for Business WritingProvisional evidence

    67% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following. 4 of 4 configured evaluation feeds currently have results.

  • Best LLM for Marketing CopyProvisional evidence

    67% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following. 4 of 4 configured evaluation feeds currently have results.

  • Best LLM for Chat & RoleplayProvisional evidence

    67% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 4 of 4 configured evaluation feeds currently have results.

Show all 25 tasks
  • Best LLM for Roleplay & CharacterProvisional evidence

    67% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 4 of 4 configured evaluation feeds currently have results.

  • Best LLM for Creative WritingProvisional evidence

    56% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 4 of 4 configured evaluation feeds currently have results.

  • Best LLM for WritingProvisional evidence

    56% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 4 of 4 configured evaluation feeds currently have results.

  • Best LLM for a General AssistantProvisional evidence

    41% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from SimpleQA Verified (Epoch AI) or LiveBench Instruction Following. 6 of 6 configured evaluation feeds currently have results.

  • Best Open-Weight LLM for Self-HostingProvisional evidence

    27% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or Route reliability. 2 of 3 configured evaluation feeds currently have results.

  • Best Value LLMProvisional evidence

    25% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or Route reliability. 2 of 3 configured evaluation feeds currently have results.

  • Best LLM for Massive ContextProvisional evidence

    20% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LMArena Document or LongBench v2. 2 of 3 configured evaluation feeds currently have results.

  • Best LLM for Fast SummariesProvisional evidence

    17% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or Route reliability. 2 of 3 configured evaluation feeds currently have results.

  • Best LLM for Literary TranslationProvisional evidence

    17% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 3 of 4 configured evaluation feeds currently have results.

  • Best LLM for Everyday TranslationProvisional evidence

    17% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 3 of 4 configured evaluation feeds currently have results.

  • Best LLM for TranslationProvisional evidence

    17% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or LiveBench Language. 3 of 4 configured evaluation feeds currently have results.

  • Best LLM for Frontend & UIProvisional evidence

    14% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from Design Arena Coding or Design Arena UI. 6 of 6 configured evaluation feeds currently have results.

  • Best LLM for JSON & Schema OutputProvisional evidence

    12% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from Berkeley Function Calling or LiveBench Data Analysis. 3 of 4 configured evaluation feeds currently have results.

  • Best LLM for Structured Data ExtractionProvisional evidence

    12% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from Berkeley Function Calling or LiveBench Data Analysis. 3 of 4 configured evaluation feeds currently have results.

  • Best LLM for RAG & Long ContextProvisional evidence

    11% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from FACTS Grounding or LMArena Document. 5 of 6 configured evaluation feeds currently have results.

  • Best LLM for Document SummarizationProvisional evidence

    10% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from FACTS Grounding or LiveBench Instruction Following. 5 of 6 configured evaluation feeds currently have results.

  • Best LLM for SummarizationProvisional evidence

    10% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from FACTS Grounding or LiveBench Instruction Following. 5 of 6 configured evaluation feeds currently have results.

  • Best Cheap LLM for High VolumeProvisional evidence

    10% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or Route reliability. 2 of 3 configured evaluation feeds currently have results.

  • Cheapest Capable LLMProvisional evidence

    10% of intended weighted task evidence across 1 independent source; broader independent confirmation is still missing from LiveBench Instruction Following or Route reliability. 2 of 3 configured evaluation feeds currently have results.

Recommendation coverage

Where this model appears

Not currently included in a published recommendation. The task evidence panel above says exactly what is confirmed and what is still missing.

Catalog data via OpenRouter and models.dev. Last checked within the past 6 hours.