Model Comparison
Gemini 3.5 Flash vs GPT-5.6 SolWhich is better in 2026?
GPT-5.6 Sol significantly outperforms across most benchmarks. Gemini 3.5 Flash is 3.3x cheaper per token.
Verdict: Gemini 3.5 Flash vs GPT-5.6 Sol — which is better?
Gemini 3.5 Flash (by Google) and GPT-5.6 Sol (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 3.5 Flash outperforms in 1 benchmarks (MMMU-Pro), while GPT-5.6 Sol is better at 4 benchmarks (GDPval-AA, MRCR v2 (8-needle), SWE-Bench Pro, Toolathlon). GPT-5.6 Sol significantly outperforms across most benchmarks.
On price, Gemini 3.5 Flash is roughly 3.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.6 Sol also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Gemini 3.5 Flash if…
- cost matters — it's about 3.3x cheaper per token
Choose GPT-5.6 Sol if…
- you want the strongest raw capability — it leads on 4 of 5 shared benchmarks
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Jul 2026
Performance Benchmarks
Comparative analysis across standard metrics
Gemini 3.5 Flash outperforms in 1 benchmarks (MMMU-Pro), while GPT-5.6 Sol is better at 4 benchmarks (GDPval-AA, MRCR v2 (8-needle), SWE-Bench Pro, Toolathlon).
GPT-5.6 Sol significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Gemini 3.5 Flash ($1.50/1M tokens) is 3.3x cheaper than GPT-5.6 Sol ($5.00/1M tokens).
For output processing, Gemini 3.5 Flash ($9.00/1M tokens) is 3.3x cheaper than GPT-5.6 Sol ($30.00/1M tokens).
In conclusion, GPT-5.6 Sol is more expensive than Gemini 3.5 Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.6 Sol accepts 1,050,000 input tokens compared to Gemini 3.5 Flash's 1,048,576 tokens. GPT-5.6 Sol can generate longer responses up to 128,000 tokens, while Gemini 3.5 Flash is limited to 65,536 tokens.
Input Capabilities
Supported data types and modalities
Both Gemini 3.5 Flash and GPT-5.6 Sol support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Gemini 3.5 Flash
GPT-5.6 Sol
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Gemini 3.5 Flash was released on 2026-05-19, while GPT-5.6 Sol was released on 2026-07-09.
GPT-5.6 Sol is 2 months newer than Gemini 3.5 Flash.
May 19, 2026
1 months ago
Jul 9, 2026
1 weeks ago
1mo newerKnowledge Cutoff
When training data ends
Gemini 3.5 Flash has a knowledge cutoff of 2026-01-31, while GPT-5.6 Sol has a cutoff of 2026-02-16.
GPT-5.6 Sol has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to Gemini 3.5 Flash (2026-01-31).
Jan 2026
Feb 2026
1 mo newerProvider Availability
Gemini 3.5 Flash is available from Google. GPT-5.6 Sol is available from OpenAI.
Gemini 3.5 Flash
GPT-5.6 Sol
Outputs Comparison
Key Takeaways
GPT-5.6 Sol
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Gemini 3.5 Flash and GPT-5.6 Sol side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Gemini 3.5 Flash vs GPT-5.6 Sol.