Claude Opus 5 vs GPT-6.1 Sol vs GPT-5.6 Sol
GPT-6.1 Sol comes out ahead, 69 to 64 and 61 on our weighted score, and it is the cheaper option too.
AnthropicClaude Opus 5
61/100- ECI162.9
- Price$5.00 / $25.00
- Context1M
- Our pick
OpenAIGPT-6.1 Sol
69/100- ECI—
- Price$2.00 / $10.00
- Context1.05M
- OpenAI
GPT-5.6 Sol
64/100- ECI161.8
- Price$4.00 / $20.00
- Context1.05M
GPT-6.1 Sol is our pick
GPT-6.1 Sol is the better all-round choice, scoring 69/100 against GPT-5.6 Sol (64) and Claude Opus 5 (61). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3, OTIS Mock AIME 2024–2025 and SimpleQA Verified), because GPT-6.1 Sol has no Capabilities Index score yet.
- CapabilityGPT-6.1 SolShared benchmarks: GPT-6.1 Sol 90.7% · GPT-5.6 Sol 88.1% · Claude Opus 5 84.6%
- Lowest priceGPT-6.1 SolGPT-6.1 Sol $4.00 · GPT-5.6 Sol $8.00 · Claude Opus 5 $10.00 per 1M tokens (3:1 blend)
- Longest contextGPT-6.1 Sol and GPT-5.6 SolGPT-6.1 Sol 1,050,000 · GPT-5.6 Sol 1,050,000 · Claude Opus 5 1,000,000 tokens
- Widest inputsSame inputsClaude Opus 5: Text, Images, PDFs · GPT-6.1 Sol: Text, Images, PDFs · GPT-5.6 Sol: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Opus 5 | GPT-6.1 Sol | GPT-5.6 Sol |
|---|---|---|---|---|
| CapabilityShared benchmarks | 50% | 85 | 91 | 88 |
| Price | 25% | 2 | 21 | 7 |
| Inputs & features | 15% | 80 | 80 | 80 |
| Context window | 10% | 60 | 61 | 61 |
| Overall | 100% | 61/100 | 69/100 | 64/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Opus 5Anthropic | GPT-6.1 SolOpenAI | GPT-5.6 SolOpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 162.9 (best) | — | 161.8 |
| ECI rank | #5 of 148 (best) | — | #8 of 148 |
| GPQA DiamondGraduate-level science questions | 93.9% | 95.4% (best) | 93.5% |
| FrontierMath Tiers 1–3Research-level mathematics | 85.6% | 93.7% (best) | 89.1% |
| OTIS Mock AIME 2024–2025Competition mathematics | 98.9% | 100% (best) | 100% (best) |
| SimpleQA VerifiedShort factual questions | 59.9% | 73.9% (best) | 69.7% |
| Price per million tokens | |||
| Input | $5.00 | $2.00 (best) | $4.00 |
| Output | $25.00 | $10.00 (best) | $20.00 |
| Cached input | $0.50 | $0.10 (best) | $0.40 |
| Blended (3:1) | $10.00 | $4.00 (best) | $8.00 |
| Long-context rate | Same rate | Over 272K: $4.00 / $15.00 | Over 272K: $8.00 / $30.00 |
| Price source | Official Anthropic API | Official OpenAI API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,050,000 tokens (best) | 1,050,000 tokens (best) |
| Max output | 128,000 tokens | 128,000 tokens | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | 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 | claude-opus-5 | gpt-6.1-sol | gpt-5.6-sol |
| API providers | 35 | 21 | 40 (best) |
| Released | Jul 24, 2026 | Sep 29, 2026 | Jul 9, 2026 |
| Knowledge cutoff | May 2026 | Apr 30, 2026 | 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.
- Claude Opus 5$100.00
- GPT-6.1 Sol$40.00
- GPT-5.6 Sol$80.00
Which should you choose?
Which is better: Claude Opus 5, GPT-6.1 Sol or GPT-5.6 Sol?
GPT-6.1 Sol is the better all-round choice, scoring 69/100 against GPT-5.6 Sol (64) and Claude Opus 5 (61). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%. Capability uses the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3, OTIS Mock AIME 2024–2025 and SimpleQA Verified), because GPT-6.1 Sol has no Capabilities Index score yet.
Which is cheaper, Claude Opus 5, GPT-6.1 Sol or GPT-5.6 Sol?
GPT-6.1 Sol is cheaper at $2.00 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 $4.00 per million tokens for GPT-6.1 Sol versus $8.00 for GPT-5.6 Sol (2× as much) and $10.00 for Claude Opus 5 (2.5× as much).
Which scores higher on benchmarks?
Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond, FrontierMath Tiers 1–3, OTIS Mock AIME 2024–2025 and SimpleQA Verified): GPT-6.1 Sol 90.7%, GPT-5.6 Sol 88.1% and Claude Opus 5 84.6%. On individual benchmarks: GPQA Diamond — GPT-6.1 Sol 95.4%, Claude Opus 5 93.9%, GPT-5.6 Sol 93.5%; FrontierMath Tiers 1–3 — GPT-6.1 Sol 93.7%, GPT-5.6 Sol 89.1%, Claude Opus 5 85.6%; OTIS Mock AIME 2024–2025 — GPT-6.1 Sol 100%, GPT-5.6 Sol 100%, Claude Opus 5 98.9%; SimpleQA Verified — GPT-6.1 Sol 73.9%, GPT-5.6 Sol 69.7%, Claude Opus 5 59.9%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Opus 5, GPT-6.1 Sol and GPT-5.6 Sol 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 and GPT-5.6 Sol have the largest context windows (1,050,000 and 1,050,000 tokens), against 1,000,000 for Claude Opus 5. Maximum output per response: Claude Opus 5 up to 128,000, GPT-6.1 Sol up to 128,000, GPT-5.6 Sol up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Opus 5 accepts text, images and PDFs; GPT-6.1 Sol accepts text, images and PDFs; GPT-5.6 Sol accepts text, images and PDFs. They handle the same number of input types.
Are any of these open source?
No. Claude Opus 5, GPT-6.1 Sol and GPT-5.6 Sol are proprietary and only available through APIs and apps.
Which is newer?
GPT-6.1 Sol is the newest, released Sep 29, 2026. Claude Opus 5 came out Jul 24, 2026; GPT-5.6 Sol came out Jul 9, 2026. Knowledge cutoff: Claude Opus 5 May 2026, GPT-6.1 Sol Apr 30, 2026, GPT-5.6 Sol 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.
