DeepSeek V4.1 Flash 1017 vs GPT-6.1 Sol vs Claude Sonnet 5.5
DeepSeek V4.1 Flash 1017 comes out ahead, 79 to 72 and 72 on our weighted score, and it is the cheaper option too.
- Our pick
DeepSeekDeepSeek V4.1 Flash 1017
79/100- ECI158.8
- Price$0.15 / $0.60
- Context1M
OpenAIGPT-6.1 Sol
72/100- ECI167.8
- Price$2.00 / $10.00
- Context1.05M
AnthropicClaude Sonnet 5.5
72/100- ECI166.7
- Price$2.00 / $10.00
- Context1M
DeepSeek V4.1 Flash 1017 is our pick
DeepSeek V4.1 Flash 1017 is the better all-round choice, scoring 79/100 against GPT-6.1 Sol (72) and Claude Sonnet 5.5 (72). It leads on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-6.1 SolCapabilities Index (ECI): GPT-6.1 Sol 167.8 · Claude Sonnet 5.5 166.7 · DeepSeek V4.1 Flash 1017 158.8
- Lowest priceDeepSeek V4.1 Flash 1017DeepSeek V4.1 Flash 1017 $0.263 · GPT-6.1 Sol $4.00 · Claude Sonnet 5.5 $4.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 SolGPT-6.1 Sol 1,050,000 · DeepSeek V4.1 Flash 1017 1,000,000 · Claude Sonnet 5.5 1,000,000 tokens
- Widest inputsGPT-6.1 Sol and Claude Sonnet 5.5DeepSeek V4.1 Flash 1017: Text, Images · GPT-6.1 Sol: Text, Images, PDFs · Claude Sonnet 5.5: Text, Images, PDFs
- Self-hostingDeepSeek V4.1 Flash 1017Publishes downloadable weights (MIT)
| Measure | Weight | DeepSeek V4.1 Flash 1017 | GPT-6.1 Sol | Claude Sonnet 5.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 87 | 99 | 97 |
| Price | 25% | 74 | 20 | 20 |
| Inputs & features | 15% | 70 | 80 | 80 |
| Context window | 10% | 60 | 61 | 60 |
| Overall | 100% | 79/100 | 72/100 | 72/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | DeepSeek V4.1 Flash 1017DeepSeek | GPT-6.1 SolOpenAI | Claude Sonnet 5.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 158.8 | 167.8 (best) | 166.7 |
| ECI rank | #19 of 165 | #4 of 165 (best) | #5 of 165 |
| GPQA DiamondGraduate-level science questions | 93.2% | 95.4% | 95.6% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 71.2% | 93.7% (best) | 88.8% |
| OTIS Mock AIME 2024–2025Competition mathematics | 99.4% | 100% (best) | 100% (best) |
| SimpleQA VerifiedShort factual questions | 42.5% | 73.9% (best) | 46.5% |
| Price per million tokens | |||
| Input | $0.15 (best) | $2.00 | $2.00 |
| Output | $0.60 (best) | $10.00 | $10.00 |
| Cached input | $0.003 (best) | $0.10 | $0.10 |
| Blended (3:1) | $0.263 (best) | $4.00 | $4.00 |
| Long-context rate | Same rate | Over 272K: $4.00 / $15.00 | Same rate |
| Price source | Official DeepSeek API | Official OpenAI API | Official Anthropic API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,050,000 tokens (best) | 1,000,000 tokens |
| Max output | 384,000 tokens (best) | 128,000 tokens | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | Yes | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · high · max | Yeslow · medium · high · xhigh · max | 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 | gpt-6.1-sol | claude-sonnet-5-5 |
| API providers | 40 (best) | 33 | 34 |
| Released | Oct 17, 2026 | Sep 29, 2026 | Sep 28, 2026 |
| Knowledge cutoff | May 2025 | Apr 30, 2026 | Jun 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 1017$2.70
- GPT-6.1 Sol$40.00
- Claude Sonnet 5.5$40.00
Which should you choose?
Which is better: DeepSeek V4.1 Flash 1017, GPT-6.1 Sol or Claude Sonnet 5.5?
DeepSeek V4.1 Flash 1017 is the better all-round choice, scoring 79/100 against GPT-6.1 Sol (72) and Claude Sonnet 5.5 (72). It leads on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, DeepSeek V4.1 Flash 1017, GPT-6.1 Sol or Claude Sonnet 5.5?
DeepSeek V4.1 Flash 1017 is cheaper at $0.15 input / $0.60 output per million tokens (official DeepSeek API price). GPT-6.1 Sol costs $2.00 input / $10.00 output per million tokens (official OpenAI API price); Claude Sonnet 5.5 costs $2.00 input / $10.00 output per million tokens (official Anthropic 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 1017 versus $4.00 for GPT-6.1 Sol (15× as much) and $4.00 for Claude Sonnet 5.5 (15× as much).
Which scores higher on benchmarks?
GPT-6.1 Sol scores higher on the Capabilities Index (ECI): GPT-6.1 Sol 167.8 (#4 of 165), Claude Sonnet 5.5 166.7 (#5 of 165) and DeepSeek V4.1 Flash 1017 158.8 (#19 of 165). The confidence ranges of the top two overlap (164.3–172.5 vs 163.6–171.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Claude Sonnet 5.5 95.6%, GPT-6.1 Sol 95.4%, DeepSeek V4.1 Flash 1017 93.2%; FrontierMath Tiers 1–3 — GPT-6.1 Sol 93.7%, Claude Sonnet 5.5 88.8%, DeepSeek V4.1 Flash 1017 71.2%; OTIS Mock AIME 2024–2025 — GPT-6.1 Sol 100%, Claude Sonnet 5.5 100%, DeepSeek V4.1 Flash 1017 99.4%; SimpleQA Verified — GPT-6.1 Sol 73.9%, Claude Sonnet 5.5 46.5%, DeepSeek V4.1 Flash 1017 42.5%.
Which is better for coding?
There are no published SWE-bench Verified results for DeepSeek V4.1 Flash 1017, GPT-6.1 Sol and Claude Sonnet 5.5 yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Sol 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-6.1 Sol has the largest context window at 1,050,000 tokens, against 1,000,000 for DeepSeek V4.1 Flash 1017 and 1,000,000 for Claude Sonnet 5.5. Maximum output per response: DeepSeek V4.1 Flash 1017 up to 384,000, GPT-6.1 Sol up to 128,000, Claude Sonnet 5.5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
DeepSeek V4.1 Flash 1017 accepts text and images; GPT-6.1 Sol accepts text, images and PDFs; Claude Sonnet 5.5 accepts text, images and PDFs. GPT-6.1 Sol handles the widest range of inputs.
Are any of these open source?
DeepSeek V4.1 Flash 1017 publishes its weights (MIT) and can be self-hosted; GPT-6.1 Sol and Claude Sonnet 5.5 is proprietary.
Which is newer?
DeepSeek V4.1 Flash 1017 is the newest, released Oct 17, 2026. GPT-6.1 Sol came out Sep 29, 2026; Claude Sonnet 5.5 came out Sep 28, 2026. Knowledge cutoff: DeepSeek V4.1 Flash 1017 May 2025, GPT-6.1 Sol Apr 30, 2026, Claude Sonnet 5.5 Jun 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 Nov 2, 2026.
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