Model Comparison

DeepSeek-V4-Flash-0731 vs GPT-5.6 LunaWhich is better in 2026?

GPT-5.6 Luna has a slight edge in benchmark performance. DeepSeek-V4-Flash-0731 is 20.0x cheaper per token.

Verdict: DeepSeek-V4-Flash-0731 vs GPT-5.6 Luna — which is better?

DeepSeek-V4-Flash-0731 (by DeepSeek) and GPT-5.6 Luna (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-0731 outperforms in 2 benchmarks (AutomationBench, Toolathlon), while GPT-5.6 Luna is better at 3 benchmarks (Agents' Last Exam, DeepSWE, Terminal-Bench 2.1). GPT-5.6 Luna has a slight edge in benchmark performance.

On price, DeepSeek-V4-Flash-0731 is roughly 20.0x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.6 Luna 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-0731 if…

  • cost matters — it's about 20.0x cheaper per token
  • you want the most recent training data — it shipped Jul 2026
  • you need open weights you can self-host or fine-tune

Choose GPT-5.6 Luna if…

  • you want the strongest raw capability — it leads on 3 of 5 shared benchmarks
  • you process long inputs — it offers a 1,050,000 token context window

Performance Benchmarks

Comparative analysis across standard metrics

5 benchmarks

DeepSeek-V4-Flash-0731 outperforms in 2 benchmarks (AutomationBench, Toolathlon), while GPT-5.6 Luna is better at 3 benchmarks (Agents' Last Exam, DeepSWE, Terminal-Bench 2.1).

GPT-5.6 Luna has a slight edge in benchmark performance.

Mon Aug 03 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

DeepSeek-V4-Flash-0731 costs less

For input processing, DeepSeek-V4-Flash-0731 ($0.09/1M tokens) is 11.1x cheaper than GPT-5.6 Luna ($1.00/1M tokens).

For output processing, DeepSeek-V4-Flash-0731 ($0.18/1M tokens) is 33.3x cheaper than GPT-5.6 Luna ($6.00/1M tokens).

In conclusion, GPT-5.6 Luna is more expensive than DeepSeek-V4-Flash-0731.*

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

Lowest available price from all providers
Mon Aug 03 2026 • llm-stats.com
DeepSeek
DeepSeek-V4-Flash-0731
Input tokens$0.09
Output tokens$0.18
Best providerDeepinfra
OpenAI
GPT-5.6 Luna
Input tokens$1.00
Output tokens$6.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.6 Luna accepts 1,050,000 input tokens compared to DeepSeek-V4-Flash-0731's 1,048,576 tokens. GPT-5.6 Luna can generate longer responses up to 128,000 tokens, while DeepSeek-V4-Flash-0731 is limited to 65,536 tokens.

DeepSeek
DeepSeek-V4-Flash-0731
Input1,048,576 tokens
Output65,536 tokens
OpenAI
GPT-5.6 Luna
Input1,050,000 tokens
Output128,000 tokens
Mon Aug 03 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.6 Luna supports multimodal inputs, whereas DeepSeek-V4-Flash-0731 does not.

GPT-5.6 Luna can handle both text and other forms of data like images, making it suitable for multimodal applications.

DeepSeek-V4-Flash-0731

Text
Images
Audio
Video

GPT-5.6 Luna

Text
Images
Audio
Video

License

Usage and distribution terms

DeepSeek-V4-Flash-0731 is licensed under MIT, while GPT-5.6 Luna uses a proprietary license.

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

DeepSeek-V4-Flash-0731

MIT

Open weights

GPT-5.6 Luna

Proprietary

Closed source

Release Timeline

When each model was launched

DeepSeek-V4-Flash-0731 was released on 2026-07-31, while GPT-5.6 Luna was released on 2026-07-09.

DeepSeek-V4-Flash-0731 is 1 month newer than GPT-5.6 Luna.

DeepSeek-V4-Flash-0731

Jul 31, 2026

3 days ago

3w newer
GPT-5.6 Luna

Jul 9, 2026

3 weeks ago

Knowledge Cutoff

When training data ends

GPT-5.6 Luna has a documented knowledge cutoff of 2026-02-16, while DeepSeek-V4-Flash-0731's cutoff date is not specified.

We can confirm GPT-5.6 Luna's training data extends to 2026-02-16, but cannot make a direct comparison without DeepSeek-V4-Flash-0731's cutoff date.

DeepSeek-V4-Flash-0731

—

GPT-5.6 Luna

Feb 2026

Provider Availability

DeepSeek-V4-Flash-0731 is available from DeepInfra, Fireworks, Novita. GPT-5.6 Luna is available from OpenAI.

DeepSeek-V4-Flash-0731

deepinfra logo
Deepinfra
Input Price:Input: $0.09/1MOutput Price:Output: $0.18/1M
fireworks logo
Fireworks
Input Price:Input: $0.14/1MOutput Price:Output: $0.28/1M
novita logo
Novita
Input Price:Input: $0.14/1MOutput Price:Output: $0.28/1M

GPT-5.6 Luna

openai logo
OpenAI
Input Price:Input: $1.00/1MOutput Price:Output: $6.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

DeepSeek
Less expensive input tokens
Less expensive output tokens
Has open weights
Higher AutomationBench score (25.1% vs 14.9%)
Higher Toolathlon score (70.3% vs 53.4%)
OpenAI
Larger context window (1,050,000 tokens)
Supports multimodal inputs
Higher Agents' Last Exam score (50.3% vs 25.2%)
Higher DeepSWE score (67.2% vs 54.4%)
Higher Terminal-Bench 2.1 score (84.7% vs 82.7%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against DeepSeek-V4-Flash-0731 and GPT-5.6 Luna side-by-side, then vote on the output you prefer.

DeepSeek-V4-Flash-0731
✓ Preferred
GPT-5.6 Luna
Open in Playground
AI Model Comparison Table
Feature
DeepSeek
DeepSeek-V4-Flash-0731
OpenAI
GPT-5.6 Luna

FAQ

Common questions about DeepSeek-V4-Flash-0731 vs GPT-5.6 Luna.

Which is better, DeepSeek-V4-Flash-0731 or GPT-5.6 Luna?

GPT-5.6 Luna has a slight edge in benchmark performance. DeepSeek-V4-Flash-0731 is made by DeepSeek and GPT-5.6 Luna is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does DeepSeek-V4-Flash-0731 compare to GPT-5.6 Luna in benchmarks?

DeepSeek-V4-Flash-0731 scores Terminal-Bench 2.1: 82.7%, CyberGym: 76.7%, Toolathlon: 70.3%, DSBench-FullStack: 68.7%, DSBench-Hard: 59.6%. GPT-5.6 Luna scores Connectors: 99.9%, HealthBench Consensus: 95.1%, GPQA: 92.3%, Search and Function-Calling: 89.7%, Capture-the-Flag Challenges (Internal): 85.2%.

Is DeepSeek-V4-Flash-0731 cheaper than GPT-5.6 Luna?

DeepSeek-V4-Flash-0731 is 11.1x cheaper for input tokens. DeepSeek-V4-Flash-0731 costs $0.09/M input and $0.18/M output via deepinfra. GPT-5.6 Luna costs $1.00/M input and $6.00/M output via openai.

What are the context window sizes for DeepSeek-V4-Flash-0731 and GPT-5.6 Luna?

DeepSeek-V4-Flash-0731 supports 1.0M tokens and GPT-5.6 Luna supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between DeepSeek-V4-Flash-0731 and GPT-5.6 Luna?

Key differences include context window (1.0M vs 1.1M), input pricing ($0.09 vs $1.00/M), multimodal support (no vs yes), licensing (MIT vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes DeepSeek-V4-Flash-0731 and GPT-5.6 Luna?

DeepSeek-V4-Flash-0731 is developed by DeepSeek and GPT-5.6 Luna is developed by OpenAI.

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