Model Comparison

o1 vs Gemini 1.5 FlashWhich is better in 2026?

o1 significantly outperforms across most benchmarks. Gemini 1.5 Flash is 100.0x cheaper per token.

Verdict: o1 vs Gemini 1.5 Flash — which is better?

o1 (by OpenAI) and Gemini 1.5 Flash (by Google) 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.

o1 outperforms in 8 benchmarks (GPQA, GSM8k, HumanEval, MATH, MathVista, MGSM, MMLU, MMMU), while Gemini 1.5 Flash is better at 0 benchmarks. o1 significantly outperforms across most benchmarks.

On price, Gemini 1.5 Flash is roughly 100.0x 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 o1 if…

  • you want the strongest raw capability — it leads on 8 of 8 shared benchmarks
  • you want the most recent training data — it shipped Dec 2024

Choose Gemini 1.5 Flash if…

  • cost matters — it's about 100.0x cheaper per token
  • you process long inputs — it offers a 1,048,576 token context window

Performance Benchmarks

Comparative analysis across standard metrics

8 benchmarks

o1 outperforms in 8 benchmarks (GPQA, GSM8k, HumanEval, MATH, MathVista, MGSM, MMLU, MMMU), while Gemini 1.5 Flash is better at 0 benchmarks.

o1 significantly outperforms across most benchmarks.

Wed Jul 01 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Gemini 1.5 Flash costs less

For input processing, o1 ($15.00/1M tokens) is 100.0x more expensive than Gemini 1.5 Flash ($0.15/1M tokens).

For output processing, o1 ($60.00/1M tokens) is 100.0x more expensive than Gemini 1.5 Flash ($0.60/1M tokens).

In conclusion, o1 is more expensive than Gemini 1.5 Flash.*

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

Lowest available price from all providers
Wed Jul 01 2026 • llm-stats.com
OpenAI
o1
Input tokens$15.00
Output tokens$60.00
Best providerAzure
Google
Gemini 1.5 Flash
Input tokens$0.15
Output tokens$0.60
Best providerGoogle
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 o1's 200,000 tokens. o1 can generate longer responses up to 100,000 tokens, while Gemini 1.5 Flash is limited to 8,192 tokens.

OpenAI
o1
Input200,000 tokens
Output100,000 tokens
Google
Gemini 1.5 Flash
Input1,048,576 tokens
Output8,192 tokens
Wed Jul 01 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Gemini 1.5 Flash supports multimodal inputs, whereas o1 does not.

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

o1

Text
Images
Audio
Video

Gemini 1.5 Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

o1

Proprietary

Closed source

Gemini 1.5 Flash

Proprietary

Closed source

Release Timeline

When each model was launched

o1 was released on 2024-12-17, while Gemini 1.5 Flash was released on 2024-05-01.

o1 is 8 months newer than Gemini 1.5 Flash.

o1

Dec 17, 2024

1.5 years ago

7mo newer
Gemini 1.5 Flash

May 1, 2024

2.2 years ago

Knowledge Cutoff

When training data ends

Gemini 1.5 Flash has a documented knowledge cutoff of 2023-11-01, while o1'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 o1's cutoff date.

o1

—

Gemini 1.5 Flash

Nov 2023

Provider Availability

o1 is available from Azure, OpenAI. Gemini 1.5 Flash is available from Google.

o1

azure logo
Azure
Input Price:Input: $15.00/1MOutput Price:Output: $60.00/1M
openai logo
OpenAI
Input Price:Input: $15.00/1MOutput Price:Output: $60.00/1M

Gemini 1.5 Flash

google logo
Google
Input Price:Input: $0.15/1MOutput Price:Output: $0.60/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

OpenAI
Higher GPQA score (78.0% vs 51.0%)
Higher GSM8k score (97.1% vs 86.2%)
Higher HumanEval score (88.1% vs 74.3%)
Higher MATH score (96.4% vs 77.9%)
Higher MathVista score (71.8% vs 65.8%)
Higher MGSM score (89.3% vs 82.6%)
Higher MMLU score (91.8% vs 78.9%)
Higher MMMU score (77.6% vs 62.3%)
Google
Larger context window (1,048,576 tokens)
Supports multimodal inputs
Less expensive input tokens
Less expensive output tokens
OpenAIo1
GoogleGemini 1.5 Flash
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Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against o1 and Gemini 1.5 Flash side-by-side, then vote on the output you prefer.

o1
✓ Preferred
Gemini 1.5 Flash
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AI Model Comparison Table
Feature
OpenAI
o1
Google
Gemini 1.5 Flash

FAQ

Common questions about o1 vs Gemini 1.5 Flash.

Which is better, o1 or Gemini 1.5 Flash?

o1 significantly outperforms across most benchmarks. o1 is made by OpenAI and Gemini 1.5 Flash is made by Google. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does o1 compare to Gemini 1.5 Flash in benchmarks?

o1 scores GSM8k: 97.1%, MATH: 96.4%, GPQA Physics: 92.8%, MMLU: 91.8%, MGSM: 89.3%. Gemini 1.5 Flash scores XSTest: 97.0%, FLEURS: 90.4%, HellaSwag: 86.5%, GSM8k: 86.2%, BIG-Bench Hard: 85.5%.

Is o1 cheaper than Gemini 1.5 Flash?

Gemini 1.5 Flash is 100.0x cheaper for input tokens. o1 costs $15.00/M input and $60.00/M output via azure. Gemini 1.5 Flash costs $0.15/M input and $0.60/M output via google.

What are the context window sizes for o1 and Gemini 1.5 Flash?

o1 supports 200K tokens and Gemini 1.5 Flash supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between o1 and Gemini 1.5 Flash?

Key differences include context window (200K vs 1.0M), input pricing ($15.00 vs $0.15/M), multimodal support (no vs yes). See the full comparison above for benchmark-by-benchmark results.

Who makes o1 and Gemini 1.5 Flash?

o1 is developed by OpenAI and Gemini 1.5 Flash is developed by Google.

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