GPT-5.6 Luna vs Claude Haiku 5.5 vs DeepSeek V4.1 Flash
Claude Haiku 5.5 comes out ahead, 83 to 76 and 72 on our weighted score, and it is the cheaper option too.
OpenAIGPT-5.6 Luna
76/100- ECI156.7
- Price$0.20 / $1.20
- Context1.05M
- Our pick
AnthropicClaude Haiku 5.5
83/100- ECI160.4
- Price$0.10 / $0.50
- Context1M
DeepSeekDeepSeek V4.1 Flash
72/100- ECI156.1
- Price$0.28 / $1.20
- Context1M
Claude Haiku 5.5 is our pick
Claude Haiku 5.5 is the better all-round choice, scoring 83/100 against GPT-5.6 Luna (76) and DeepSeek V4.1 Flash (72). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Haiku 5.5Capabilities Index (ECI): Claude Haiku 5.5 160.4 · GPT-5.6 Luna 156.7 · DeepSeek V4.1 Flash 156.1
- Lowest priceClaude Haiku 5.5Claude Haiku 5.5 $0.20 · GPT-5.6 Luna $0.45 · DeepSeek V4.1 Flash $0.51 per 1M tokens (3:1 blend)
- Longest contextGPT-5.6 LunaGPT-5.6 Luna 1,050,000 · Claude Haiku 5.5 1,000,000 · DeepSeek V4.1 Flash 1,000,000 tokens
- Widest inputsGPT-5.6 Luna and Claude Haiku 5.5GPT-5.6 Luna: Text, Images, PDFs · Claude Haiku 5.5: Text, Images, PDFs · DeepSeek V4.1 Flash: Text, Images
- Self-hostingDeepSeek V4.1 FlashPublishes downloadable weights (MIT)
| Measure | Weight | GPT-5.6 Luna | Claude Haiku 5.5 | DeepSeek V4.1 Flash |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 85 | 89 | 84 |
| Price | 25% | 64 | 80 | 61 |
| Inputs & features | 15% | 80 | 80 | 60 |
| Context window | 10% | 61 | 60 | 60 |
| Overall | 100% | 76/100 | 83/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.6 LunaOpenAI | Claude Haiku 5.5Anthropic | DeepSeek V4.1 FlashDeepSeek |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 156.7 | 160.4 (best) | 156.1 |
| ECI rank | #30 of 165 | #14 of 165 (best) | #34 of 165 |
| GPQA DiamondGraduate-level science questions | 91.6% (best) | 89.7% | 89.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 82.1% (best) | 75.1% | 67.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 98.3% | 98.9% (best) | 98.3% |
| SimpleQA VerifiedShort factual questions | 41.0% | 23.8% | 42.9% (best) |
| Price per million tokens | |||
| Input | $0.20 | $0.10 (best) | $0.28 |
| Output | $1.20 | $0.50 (best) | $1.20 |
| Cached input | $0.02 | $0.01 (best) | — |
| Blended (3:1) | $0.45 | $0.20 (best) | $0.51 |
| Long-context rate | Over 272K: $0.40 / $1.80 | Over 100K: $0.50 / $2.50 | Same rate |
| Price source | Official OpenAI API | Official Anthropic API | Median of 61 providers |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens | 384,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | No |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high · xhigh · max | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | No |
| Availability | |||
| Weights | Proprietary | Proprietary | OpenMIT |
| API model ID | gpt-5.6-luna | claude-haiku-5-5 | — |
| API providers | 47 | 33 | 64 (best) |
| Released | Jul 9, 2026 | Oct 7, 2026 | Sep 10, 2026 |
| Knowledge cutoff | Feb 16, 2026 | Jun 2026 | May 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5.6 Luna$4.40
- Claude Haiku 5.5$2.00
- DeepSeek V4.1 Flash$5.20
Which should you choose?
Which is better: GPT-5.6 Luna, Claude Haiku 5.5 or DeepSeek V4.1 Flash?
Claude Haiku 5.5 is the better all-round choice, scoring 83/100 against GPT-5.6 Luna (76) and DeepSeek V4.1 Flash (72). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.6 Luna, Claude Haiku 5.5 or DeepSeek V4.1 Flash?
Claude Haiku 5.5 is cheaper at $0.10 input / $0.50 output per million tokens (official Anthropic API price). GPT-5.6 Luna costs $0.20 input / $1.20 output per million tokens (official OpenAI API price); DeepSeek V4.1 Flash costs $0.28 input / $1.20 output per million tokens (median across 61 API providers). At a typical mix of three input tokens to one output token, that is $0.20 per million tokens for Claude Haiku 5.5 versus $0.45 for GPT-5.6 Luna (2.3× as much) and $0.51 for DeepSeek V4.1 Flash (2.6× as much).
Which scores higher on benchmarks?
Claude Haiku 5.5 scores higher on the Capabilities Index (ECI): Claude Haiku 5.5 160.4 (#14 of 165), GPT-5.6 Luna 156.7 (#30 of 165) and DeepSeek V4.1 Flash 156.1 (#34 of 165). The confidence ranges of the top two overlap (157.3–163.8 vs 154.2–159.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.6 Luna 91.6%, DeepSeek V4.1 Flash 89.8%, Claude Haiku 5.5 89.7%; FrontierMath Tiers 1–3 — GPT-5.6 Luna 82.1%, Claude Haiku 5.5 75.1%, DeepSeek V4.1 Flash 67.4%; OTIS Mock AIME 2024–2025 — Claude Haiku 5.5 98.9%, GPT-5.6 Luna 98.3%, DeepSeek V4.1 Flash 98.3%; SimpleQA Verified — DeepSeek V4.1 Flash 42.9%, GPT-5.6 Luna 41.0%, Claude Haiku 5.5 23.8%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.6 Luna, Claude Haiku 5.5 and DeepSeek V4.1 Flash yet, so there is no like-for-like coding score. On overall capability, Claude Haiku 5.5 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 has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Haiku 5.5 and 1,000,000 for DeepSeek V4.1 Flash. Maximum output per response: GPT-5.6 Luna up to 128,000, Claude Haiku 5.5 up to 128,000, DeepSeek V4.1 Flash up to 384,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.6 Luna accepts text, images and PDFs; Claude Haiku 5.5 accepts text, images and PDFs; DeepSeek V4.1 Flash accepts text and images. GPT-5.6 Luna 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; GPT-5.6 Luna and Claude Haiku 5.5 is proprietary.
Which is newer?
Claude Haiku 5.5 is the newest, released Oct 7, 2026. DeepSeek V4.1 Flash came out Sep 10, 2026; GPT-5.6 Luna came out Jul 9, 2026. Knowledge cutoff: GPT-5.6 Luna Feb 16, 2026, Claude Haiku 5.5 Jun 2026, DeepSeek V4.1 Flash May 2025.
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 Nov 2, 2026.
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