GPT-5.1 vs GPT-5.6 Sol vs Claude Opus 5
Too close to call on our weighted score (GPT-5.6 Sol 66, Claude Opus 5 66, GPT-5.1 60). The right pick depends on what you value most.
OpenAIGPT-5.1
60/100- ECI149.7
- Price$1.25 / $10.00
- Context400K
- OpenAI
GPT-5.6 Sol
66/100- ECI161.8
- Price$4.00 / $20.00
- Context1.05M
AnthropicClaude Opus 5
66/100- ECI162.9
- Price$5.00 / $25.00
- Context1M
Too close to call
It is close. Our weighted score puts them within a point (GPT-5.6 Sol 66/100, Claude Opus 5 66/100, GPT-5.1 60/100), so choose by what matters most for your work: Claude Opus 5 for raw capability, GPT-5.1 on price and GPT-5.6 Sol for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 5Capabilities Index (ECI): Claude Opus 5 162.9 · GPT-5.6 Sol 161.8 · GPT-5.1 149.7
- Lowest priceGPT-5.1GPT-5.1 $3.44 · GPT-5.6 Sol $8.00 · Claude Opus 5 $10.00 per 1M tokens (3:1 blend)
- Longest contextGPT-5.6 SolGPT-5.6 Sol 1,050,000 · Claude Opus 5 1,000,000 · GPT-5.1 400,000 tokens
- Widest inputsGPT-5.6 Sol and Claude Opus 5GPT-5.1: Text, Images · GPT-5.6 Sol: Text, Images, PDFs · Claude Opus 5: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-5.1 | GPT-5.6 Sol | Claude Opus 5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 78 | 93 | 94 |
| Price | 25% | 24 | 7 | 2 |
| Inputs & features | 15% | 70 | 80 | 80 |
| Context window | 10% | 44 | 61 | 60 |
| Overall | 100% | 60/100 | 66/100 | 66/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.1OpenAI | GPT-5.6 SolOpenAI | Claude Opus 5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 149.7 | 161.8 | 162.9 (best) |
| ECI rank | #52 of 148 | #8 of 148 | #5 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 87.6% | 93.5% | 93.9% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | — | 89.1% (best) | 85.6% |
| OTIS Mock AIME 2024–2025Competition mathematics | 88.6% | 100% (best) | 98.9% |
| SWE-bench VerifiedFixing real GitHub issues | 68.0% | — | — |
| SimpleQA VerifiedShort factual questions | 48.0% | 69.7% (best) | 59.9% |
| Price per million tokens | |||
| Input | $1.25 (best) | $4.00 | $5.00 |
| Output | $10.00 (best) | $20.00 | $25.00 |
| Cached input | $0.125 (best) | $0.40 | $0.50 |
| Blended (3:1) | $3.44 (best) | $8.00 | $10.00 |
| Long-context rate | Same rate | Over 272K: $8.00 / $30.00 | Same rate |
| Price source | Official OpenAI API | Official OpenAI API | Official Anthropic API |
| Limits | |||
| Context window | 400,000 tokens | 1,050,000 tokens (best) | 1,000,000 tokens |
| Max output | 128,000 tokens | 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 · medium · high | Yeslow · medium · high · xhigh · max | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gpt-5.1 | gpt-5.6-sol | claude-opus-5 |
| API providers | 21 | 40 (best) | 35 |
| Released | Nov 13, 2025 | Jul 9, 2026 | Jul 24, 2026 |
| Knowledge cutoff | Sep 30, 2024 | Feb 16, 2026 | May 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5.1$32.50
- GPT-5.6 Sol$80.00
- Claude Opus 5$100.00
Which should you choose?
Which is better: GPT-5.1, GPT-5.6 Sol or Claude Opus 5?
It is close. Our weighted score puts them within a point (GPT-5.6 Sol 66/100, Claude Opus 5 66/100, GPT-5.1 60/100), so choose by what matters most for your work: Claude Opus 5 for raw capability, GPT-5.1 on price and GPT-5.6 Sol for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.1, GPT-5.6 Sol or Claude Opus 5?
GPT-5.1 is cheaper at $1.25 input / $10.00 output per million tokens (official OpenAI API price). GPT-5.6 Sol costs $4.00 input / $20.00 output per million tokens (official OpenAI API price); Claude Opus 5 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for GPT-5.1 versus $8.00 for GPT-5.6 Sol (2.3× as much) and $10.00 for Claude Opus 5 (2.9× as much).
Which scores higher on benchmarks?
Claude Opus 5 scores higher on the Capabilities Index (ECI): Claude Opus 5 162.9 (#5 of 148), GPT-5.6 Sol 161.8 (#8 of 148) and GPT-5.1 149.7 (#52 of 148). The confidence ranges of the top two overlap (160.2–166.7 vs 159.3–165.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Claude Opus 5 93.9%, GPT-5.6 Sol 93.5%, GPT-5.1 87.6%; OTIS Mock AIME 2024–2025 — GPT-5.6 Sol 100%, Claude Opus 5 98.9%, GPT-5.1 88.6%; SimpleQA Verified — GPT-5.6 Sol 69.7%, Claude Opus 5 59.9%, GPT-5.1 48.0%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.6 Sol and Claude Opus 5 yet, so there is no like-for-like coding score. On overall capability, Claude Opus 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 Sol has the largest context window at 1,050,000 tokens, against 1,000,000 for Claude Opus 5 and 400,000 for GPT-5.1. Maximum output per response: GPT-5.1 up to 128,000, GPT-5.6 Sol up to 128,000, Claude Opus 5 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.1 accepts text and images; GPT-5.6 Sol accepts text, images and PDFs; Claude Opus 5 accepts text, images and PDFs. GPT-5.6 Sol handles the widest range of inputs.
Are any of these open source?
No. GPT-5.1, GPT-5.6 Sol and Claude Opus 5 are proprietary and only available through APIs and apps.
Which is newer?
Claude Opus 5 is the newest, released Jul 24, 2026. GPT-5.6 Sol came out Jul 9, 2026; GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 Sep 30, 2024, GPT-5.6 Sol Feb 16, 2026, Claude Opus 5 May 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.
