Model Comparison

Gemini 1.5 Flash vs GPT OSS 20BWhich is better in 2026?

GPT OSS 20B significantly outperforms across most benchmarks. GPT OSS 20B is 3.0x cheaper per token.

Verdict: Gemini 1.5 Flash vs GPT OSS 20B — which is better?

Gemini 1.5 Flash (by Google) 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.

Gemini 1.5 Flash outperforms in 0 benchmarks, while GPT OSS 20B is better at 2 benchmarks (GPQA, MMLU). GPT OSS 20B significantly outperforms across most benchmarks.

On price, GPT OSS 20B is roughly 3.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Gemini 1.5 Flash also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.

Choose Gemini 1.5 Flash if…

  • you process long inputs — it offers a 1,048,576 token context window

Choose GPT OSS 20B if…

  • you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • cost matters — it's about 3.0x cheaper per token
  • you want the most recent training data — it shipped Aug 2025
  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Gemini 1.5 Flash outperforms in 0 benchmarks, while GPT OSS 20B is better at 2 benchmarks (GPQA, MMLU).

GPT OSS 20B significantly outperforms across most benchmarks.

Sun Jul 26 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT OSS 20B costs less

For input processing, Gemini 1.5 Flash ($0.15/1M tokens) is 3.0x more expensive than GPT OSS 20B ($0.05/1M tokens).

For output processing, Gemini 1.5 Flash ($0.60/1M tokens) is 3.0x more expensive than GPT OSS 20B ($0.20/1M tokens).

In conclusion, Gemini 1.5 Flash is more expensive than GPT OSS 20B.*

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

Lowest available price from all providers
Sun Jul 26 2026 • llm-stats.com
Google
Gemini 1.5 Flash
Input tokens$0.15
Output tokens$0.60
Best providerGoogle
OpenAI
GPT OSS 20B
Input tokens$0.05
Output tokens$0.20
Best providerNovita
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Gemini 1.5 Flash accepts 1,048,576 input tokens compared to GPT OSS 20B's 131,072 tokens. GPT OSS 20B can generate longer responses up to 32,768 tokens, while Gemini 1.5 Flash is limited to 8,192 tokens.

Google
Gemini 1.5 Flash
Input1,048,576 tokens
Output8,192 tokens
OpenAI
GPT OSS 20B
Input131,072 tokens
Output32,768 tokens
Sun Jul 26 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Gemini 1.5 Flash supports multimodal inputs, whereas GPT OSS 20B does not.

Gemini 1.5 Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

Gemini 1.5 Flash

Text
Images
Audio
Video

GPT OSS 20B

Text
Images
Audio
Video

License

Usage and distribution terms

Gemini 1.5 Flash is licensed under a proprietary license, while GPT OSS 20B uses Apache 2.0.

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

Gemini 1.5 Flash

Proprietary

Closed source

GPT OSS 20B

Apache 2.0

Open weights

Release Timeline

When each model was launched

Gemini 1.5 Flash was released on 2024-05-01, while GPT OSS 20B was released on 2025-08-05.

GPT OSS 20B is 15 months newer than Gemini 1.5 Flash.

Gemini 1.5 Flash

May 1, 2024

2.2 years ago

GPT OSS 20B

Aug 5, 2025

11 months ago

1.3yr newer

Knowledge Cutoff

When training data ends

Gemini 1.5 Flash has a documented knowledge cutoff of 2023-11-01, while GPT OSS 20B's cutoff date is not specified.

We can confirm Gemini 1.5 Flash's training data extends to 2023-11-01, but cannot make a direct comparison without GPT OSS 20B's cutoff date.

Gemini 1.5 Flash

Nov 2023

GPT OSS 20B

—

Provider Availability

Gemini 1.5 Flash is available from Google. GPT OSS 20B is available from Novita, Fireworks, Groq, OpenAI.

Gemini 1.5 Flash

google logo
Google
Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M

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

Google
Larger context window (1,048,576 tokens)
Supports multimodal inputs
OpenAI
Less expensive input tokens
Less expensive output tokens
Has open weights
Higher GPQA score (71.5% vs 51.0%)
Higher MMLU score (85.3% vs 78.9%)
GoogleGemini 1.5 Flash
OpenAIGPT OSS 20B
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Gemini 1.5 Flash and GPT OSS 20B side-by-side, then vote on the output you prefer.

Gemini 1.5 Flash
✓ Preferred
GPT OSS 20B
Open in Playground
AI Model Comparison Table
Feature
Google
Gemini 1.5 Flash
OpenAI
GPT OSS 20B

FAQ

Common questions about Gemini 1.5 Flash vs GPT OSS 20B.

Which is better, Gemini 1.5 Flash or GPT OSS 20B?

GPT OSS 20B significantly outperforms across most benchmarks. Gemini 1.5 Flash is made by Google 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 Gemini 1.5 Flash compare to GPT OSS 20B in benchmarks?

Gemini 1.5 Flash scores XSTest: 97.0%, FLEURS: 90.4%, HellaSwag: 86.5%, GSM8k: 86.2%, BIG-Bench Hard: 85.5%. GPT OSS 20B scores MMLU: 85.3%, CodeForces: 74.3%, GPQA: 71.5%, TAU-bench Retail: 54.8%, HealthBench: 42.5%.

Is Gemini 1.5 Flash cheaper than GPT OSS 20B?

GPT OSS 20B is 3.0x cheaper for input tokens. Gemini 1.5 Flash costs $0.15/M input and $0.60/M output via google. GPT OSS 20B costs $0.05/M input and $0.20/M output via novita.

What are the context window sizes for Gemini 1.5 Flash and GPT OSS 20B?

Gemini 1.5 Flash supports 1.0M 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 Gemini 1.5 Flash and GPT OSS 20B?

Key differences include context window (1.0M vs 131K), input pricing ($0.15 vs $0.05/M), multimodal support (yes vs no), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 1.5 Flash and GPT OSS 20B?

Gemini 1.5 Flash is developed by Google and GPT OSS 20B is developed by OpenAI.

Related comparisons