Model Comparison
DeepSeek-V4-Flash-Max vs GPT-5.5Which is better in 2026?
GPT-5.5 significantly outperforms across most benchmarks. DeepSeek-V4-Flash-Max is 90.0x cheaper per token.
Verdict: DeepSeek-V4-Flash-Max vs GPT-5.5 — which is better?
DeepSeek-V4-Flash-Max (by DeepSeek) and GPT-5.5 (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.
DeepSeek-V4-Flash-Max outperforms in 1 benchmarks (GDPval-AA), while GPT-5.5 is better at 7 benchmarks (BrowseComp, GPQA, Humanity's Last Exam, MCP Atlas, SWE-Bench Pro, Terminal-Bench 2.0, Toolathlon). GPT-5.5 significantly outperforms across most benchmarks.
On price, DeepSeek-V4-Flash-Max is roughly 90.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.5 also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose DeepSeek-V4-Flash-Max if…
- cost matters — it's about 90.0x cheaper per token
- you need open weights you can self-host or fine-tune
Choose GPT-5.5 if…
- you want the strongest raw capability — it leads on 7 of 8 shared benchmarks
- you process long inputs — it offers a 1,050,000 token context window
Performance Benchmarks
Comparative analysis across standard metrics
DeepSeek-V4-Flash-Max outperforms in 1 benchmarks (GDPval-AA), while GPT-5.5 is better at 7 benchmarks (BrowseComp, GPQA, Humanity's Last Exam, MCP Atlas, SWE-Bench Pro, Terminal-Bench 2.0, Toolathlon).
GPT-5.5 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, DeepSeek-V4-Flash-Max ($0.10/1M tokens) is 50.0x cheaper than GPT-5.5 ($5.00/1M tokens).
For output processing, DeepSeek-V4-Flash-Max ($0.20/1M tokens) is 150.0x cheaper than GPT-5.5 ($30.00/1M tokens).
In conclusion, GPT-5.5 is more expensive than DeepSeek-V4-Flash-Max.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.5 accepts 1,050,000 input tokens compared to DeepSeek-V4-Flash-Max's 1,048,576 tokens. GPT-5.5 can generate longer responses up to 128,000 tokens, while DeepSeek-V4-Flash-Max is limited to 65,536 tokens.
Input Capabilities
Supported data types and modalities
GPT-5.5 supports multimodal inputs, whereas DeepSeek-V4-Flash-Max does not.
GPT-5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.
DeepSeek-V4-Flash-Max
GPT-5.5
License
Usage and distribution terms
DeepSeek-V4-Flash-Max is licensed under MIT, while GPT-5.5 uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
Both models were released on 2026-04-23.
They likely represent similar generations of model development.
Apr 23, 2026
2 months ago
Apr 23, 2026
2 months ago
Knowledge Cutoff
When training data ends
GPT-5.5 has a documented knowledge cutoff of 2025-12-01, while DeepSeek-V4-Flash-Max's cutoff date is not specified.
We can confirm GPT-5.5's training data extends to 2025-12-01, but cannot make a direct comparison without DeepSeek-V4-Flash-Max's cutoff date.
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Dec 2025
Provider Availability
DeepSeek-V4-Flash-Max is available from DeepInfra, DeepSeek, Fireworks, Novita. GPT-5.5 is available from OpenAI.
DeepSeek-V4-Flash-Max
GPT-5.5
Outputs Comparison
Key Takeaways
GPT-5.5
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against DeepSeek-V4-Flash-Max and GPT-5.5 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about DeepSeek-V4-Flash-Max vs GPT-5.5.