DeepSeek V4.1 Flash vs Gemini 3.8 Flash vs GPT-5.6 Luna
Too close to call on our weighted score (DeepSeek V4.1 Flash 78, GPT-5.6 Luna 78, Gemini 3.8 Flash 75). The right pick depends on what you value most.
DeepSeekDeepSeek V4.1 Flash
78/100- ECI155.0
- Price$0.15 / $0.60
- Context1M
GoogleGemini 3.8 Flash
75/100- ECI156.9
- Price$0.75 / $3.75
- Context1.05M
OpenAIGPT-5.6 Luna
78/100- ECI156.5
- Price$0.20 / $1.20
- Context1.05M
Too close to call
It is close. Our weighted score puts them within a point (DeepSeek V4.1 Flash 78/100, GPT-5.6 Luna 78/100, Gemini 3.8 Flash 75/100), so choose by what matters most for your work: Gemini 3.8 Flash for raw capability and DeepSeek V4.1 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGemini 3.8 FlashCapabilities Index (ECI): Gemini 3.8 Flash 156.9 · GPT-5.6 Luna 156.5 · DeepSeek V4.1 Flash 155.0
- Lowest priceDeepSeek V4.1 FlashDeepSeek V4.1 Flash $0.263 · GPT-5.6 Luna $0.45 · Gemini 3.8 Flash $1.50 per 1M tokens (3:1 blend)
- Longest contextGPT-5.6 Luna and Gemini 3.8 FlashGPT-5.6 Luna 1,050,000 · Gemini 3.8 Flash 1,048,576 · DeepSeek V4.1 Flash 1,000,000 tokens
- Widest inputsGemini 3.8 FlashDeepSeek V4.1 Flash: Text, Images · Gemini 3.8 Flash: Text, Images, PDFs, Audio, Video · GPT-5.6 Luna: Text, Images, PDFs
- Self-hostingDeepSeek V4.1 FlashPublishes downloadable weights (MIT)
| Measure | Weight | DeepSeek V4.1 Flash | Gemini 3.8 Flash | GPT-5.6 Luna |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 87 | 86 |
| Price | 25% | 77 | 42 | 66 |
| Inputs & features | 15% | 70 | 100 | 80 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 78/100 | 75/100 | 78/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | DeepSeek V4.1 FlashDeepSeek | Gemini 3.8 FlashGoogle | GPT-5.6 LunaOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 155.0 | 156.9 (best) | 156.5 |
| ECI rank | #29 of 148 | #15 of 148 (best) | #21 of 148 |
| GPQA DiamondGraduate-level science questions | — | 95.4% (best) | 91.6% |
| FrontierMath Tiers 1–3Research-level mathematics | — | 68.4% | 82.1% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | — | 98.9% (best) | 98.3% |
| SimpleQA VerifiedShort factual questions | — | 69.7% (best) | 41.0% |
| Price per million tokens | |||
| Input | $0.15 (best) | $0.75 | $0.20 |
| Output | $0.60 (best) | $3.75 | $1.20 |
| Cached input | $0.003 (best) | $0.075 | $0.02 |
| Blended (3:1) | $0.263 (best) | $1.50 | $0.45 |
| Long-context rate | Same rate | Same rate | Over 272K: $0.40 / $1.80 |
| Price source | Official DeepSeek API | Official Google API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens | 1,050,000 tokens (best) |
| Max output | 384,000 tokens (best) | 65,536 tokens | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | Yes | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · high · max | Yeslow · medium · high | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | OpenMIT | Proprietary | Proprietary |
| API model ID | deepseek-flash | gemini-3.8-flash | gpt-5.6-luna |
| API providers | 50 (best) | 21 | 38 |
| Released | Sep 10, 2026 | Sep 2, 2026 | Jul 9, 2026 |
| Knowledge cutoff | May 2025 | — | Feb 16, 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- DeepSeek V4.1 Flash$2.70
- Gemini 3.8 Flash$15.00
- GPT-5.6 Luna$4.40
Which should you choose?
Which is better: DeepSeek V4.1 Flash, Gemini 3.8 Flash or GPT-5.6 Luna?
It is close. Our weighted score puts them within a point (DeepSeek V4.1 Flash 78/100, GPT-5.6 Luna 78/100, Gemini 3.8 Flash 75/100), so choose by what matters most for your work: Gemini 3.8 Flash for raw capability and DeepSeek V4.1 Flash on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, DeepSeek V4.1 Flash, Gemini 3.8 Flash or GPT-5.6 Luna?
DeepSeek V4.1 Flash is cheaper at $0.15 input / $0.60 output per million tokens (official DeepSeek API price). GPT-5.6 Luna costs $0.20 input / $1.20 output per million tokens (official OpenAI API price); Gemini 3.8 Flash costs $0.75 input / $3.75 output per million tokens (official Google API price). At a typical mix of three input tokens to one output token, that is $0.263 per million tokens for DeepSeek V4.1 Flash versus $0.45 for GPT-5.6 Luna (1.7× as much) and $1.50 for Gemini 3.8 Flash (5.7× as much).
Which scores higher on benchmarks?
Gemini 3.8 Flash scores higher on the Capabilities Index (ECI): Gemini 3.8 Flash 156.9 (#15 of 148), GPT-5.6 Luna 156.5 (#21 of 148) and DeepSeek V4.1 Flash 155.0 (#29 of 148). The confidence ranges of the top two overlap (154.6–160.4 vs 154.1–158.6), so treat the gap as small.
Which is better for coding?
There are no published SWE-bench Verified results for DeepSeek V4.1 Flash, Gemini 3.8 Flash and GPT-5.6 Luna yet, so there is no like-for-like coding score. On overall capability, Gemini 3.8 Flash leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
GPT-5.6 Luna and Gemini 3.8 Flash have the largest context windows (1,050,000 and 1,048,576 tokens), against 1,000,000 for DeepSeek V4.1 Flash. Maximum output per response: DeepSeek V4.1 Flash up to 384,000, Gemini 3.8 Flash up to 65,536, GPT-5.6 Luna up to 128,000 tokens.
Which can read images, PDFs, audio or video?
DeepSeek V4.1 Flash accepts text and images; Gemini 3.8 Flash accepts text, images, PDFs, audio and video; GPT-5.6 Luna accepts text, images and PDFs. Gemini 3.8 Flash handles the widest range of inputs.
Are any of these open source?
DeepSeek V4.1 Flash publishes its weights (MIT) and can be self-hosted; Gemini 3.8 Flash and GPT-5.6 Luna is proprietary.
Which is newer?
DeepSeek V4.1 Flash is the newest, released Sep 10, 2026. Gemini 3.8 Flash came out Sep 2, 2026; GPT-5.6 Luna came out Jul 9, 2026. Knowledge cutoff: DeepSeek V4.1 Flash May 2025, GPT-5.6 Luna Feb 16, 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
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