The AI arena is free today

Open Playground

Model Comparison

GLM-4.5 vs GPT OSS 20BWhich is better in 2026?

GLM-4.5 significantly outperforms across most benchmarks. GPT OSS 20B is 8.0x cheaper per token.

Verdict: GLM-4.5 vs GPT OSS 20B — which is better?

GLM-4.5 (by Zhipu AI) and GPT OSS 20B (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

GLM-4.5 outperforms in 3 benchmarks (GPQA, Humanity's Last Exam, TAU-bench Retail), while GPT OSS 20B is better at 0 benchmarks. GLM-4.5 significantly outperforms across most benchmarks.

On price, GPT OSS 20B is roughly 8.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Choose GLM-4.5 if…

  • you want the strongest raw capability — it leads on 3 of 3 shared benchmarks

Choose GPT OSS 20B if…

  • cost matters — it's about 8.0x cheaper per token
  • you want the most recent training data — it shipped Aug 2025

Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GLM-4.5 outperforms in 3 benchmarks (GPQA, Humanity's Last Exam, TAU-bench Retail), while GPT OSS 20B is better at 0 benchmarks.

GLM-4.5 significantly outperforms across most benchmarks.

Fri Aug 07 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 20B costs less

For input processing, GLM-4.5 ($0.40/1M tokens) is 8.0x more expensive than GPT OSS 20B ($0.05/1M tokens).

For output processing, GLM-4.5 ($1.60/1M tokens) is 8.0x more expensive than GPT OSS 20B ($0.20/1M tokens).

In conclusion, GLM-4.5 is more expensive than GPT OSS 20B.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Fri Aug 07 2026 • llm-stats.com
Zhipu AI
GLM-4.5
Input tokens$0.40
Output tokens$1.60
Best providerDeepinfra
OpenAI
GPT OSS 20B
Input tokens$0.05
Output tokens$0.20
Best providerNovita
Notice missing or incorrect data?Start an Issue→

Model Size

Parameter count comparison

334.1B diff

GLM-4.5 has 334.1B more parameters than GPT OSS 20B, making it 1598.6% larger.

Zhipu AI
GLM-4.5
355.0Bparameters
OpenAI
GPT OSS 20B
20.9Bparameters
355.0B
GLM-4.5
20.9B
GPT OSS 20B

Context Window

Maximum input and output token capacity

Both models have the same input context window of 131,072 tokens. GLM-4.5 can generate longer responses up to 131,072 tokens, while GPT OSS 20B is limited to 32,768 tokens.

Zhipu AI
GLM-4.5
Input131,072 tokens
Output131,072 tokens
OpenAI
GPT OSS 20B
Input131,072 tokens
Output32,768 tokens
Fri Aug 07 2026 • llm-stats.com

License

Usage and distribution terms

GLM-4.5 is licensed under MIT, while GPT OSS 20B uses Apache 2.0.

License differences may affect how you can use these models in commercial or open-source projects.

GLM-4.5

MIT

Open weights

GPT OSS 20B

Apache 2.0

Open weights

Release Timeline

When each model was launched

GLM-4.5 was released on 2025-07-28, while GPT OSS 20B was released on 2025-08-05.

GPT OSS 20B is 0 month newer than GLM-4.5.

GLM-4.5

Jul 28, 2025

1.0 years ago

GPT OSS 20B

Aug 5, 2025

1.0 years ago

1w newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

GLM-4.5 is available from DeepInfra, Fireworks, Novita. GPT OSS 20B is available from Novita, Fireworks, Groq, OpenAI.

GLM-4.5

deepinfra logo
Deepinfra
Input Price:Input: $0.40/1MOutput Price:Output: $1.60/1M
fireworks logo
Fireworks
Input Price:Input: $0.55/1MOutput Price:Output: $2.19/1M
novita logo
Novita
Input Price:Input: $0.60/1MOutput Price:Output: $2.20/1M

GPT OSS 20B

novita logo
Novita
Input Price:Input: $0.05/1MOutput Price:Output: $0.20/1M
fireworks logo
Fireworks
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
groq logo
Groq
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
openai logo
OpenAI
Input Price:Input: $0.10/1MOutput Price:Output: $0.50/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Zhipu AI
Higher GPQA score (79.1% vs 71.5%)
Higher Humanity's Last Exam score (14.4% vs 10.9%)
Higher TAU-bench Retail score (79.7% vs 54.8%)
OpenAI
Less expensive input tokens
Less expensive output tokens

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GLM-4.5 and GPT OSS 20B side-by-side, then vote on the output you prefer.

GLM-4.5
✓ Preferred
GPT OSS 20B
Open in Playground
AI Model Comparison Table
Feature
Zhipu AI
GLM-4.5
OpenAI
GPT OSS 20B

FAQ

Common questions about GLM-4.5 vs GPT OSS 20B.

Which is better, GLM-4.5 or GPT OSS 20B?

GLM-4.5 significantly outperforms across most benchmarks. GLM-4.5 is made by Zhipu AI and GPT OSS 20B is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GLM-4.5 compare to GPT OSS 20B in benchmarks?

GLM-4.5 scores MATH-500: 98.2%, AIME 2024: 91.0%, MMLU-Pro: 84.6%, TAU-bench Retail: 79.7%, GPQA: 79.1%. GPT OSS 20B scores MMLU: 85.3%, CodeForces: 74.3%, GPQA: 71.5%, TAU-bench Retail: 54.8%, HealthBench: 42.5%.

Is GLM-4.5 cheaper than GPT OSS 20B?

GPT OSS 20B is 8.0x cheaper for input tokens. GLM-4.5 costs $0.40/M input and $1.60/M output via deepinfra. GPT OSS 20B costs $0.05/M input and $0.20/M output via novita.

What are the context window sizes for GLM-4.5 and GPT OSS 20B?

GLM-4.5 supports 131K tokens and GPT OSS 20B supports 131K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GLM-4.5 and GPT OSS 20B?

Key differences include input pricing ($0.40 vs $0.05/M), licensing (MIT vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes GLM-4.5 and GPT OSS 20B?

GLM-4.5 is developed by Zhipu AI and GPT OSS 20B is developed by OpenAI.

Related comparisons