GPT-5.6 Sol vs GPT-5 Pro vs Claude Opus 4.5
GPT-5.6 Sol comes out ahead, 66 to 55 and 54 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-5.6 Sol
66/100- ECI161.8
- Price$4.00 / $20.00
- Context1.05M
- OpenAI
GPT-5 Pro
54/100- ECI150.3
- Price$15.00 / $120.00
- Context400K
AnthropicClaude Opus 4.5
55/100- ECI150.1
- Price$5.00 / $25.00
- Context200K
GPT-5.6 Sol is our pick
GPT-5.6 Sol is the better all-round choice, scoring 66/100 against Claude Opus 4.5 (55) and GPT-5 Pro (54). It leads on capability, price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-5.6 SolCapabilities Index (ECI): GPT-5.6 Sol 161.8 · GPT-5 Pro 150.3 · Claude Opus 4.5 150.1
- Lowest priceGPT-5.6 SolGPT-5.6 Sol $8.00 · Claude Opus 4.5 $10.00 · GPT-5 Pro $41.25 per 1M tokens (3:1 blend)
- Longest contextGPT-5.6 SolGPT-5.6 Sol 1,050,000 · GPT-5 Pro 400,000 · Claude Opus 4.5 200,000 tokens
- Widest inputsGPT-5.6 Sol and Claude Opus 4.5GPT-5.6 Sol: Text, Images, PDFs · GPT-5 Pro: Text, Images · Claude Opus 4.5: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-5.6 Sol | GPT-5 Pro | Claude Opus 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 93 | 78 | 78 |
| Price | 25% | 7 | 0 | 2 |
| Inputs & features | 15% | 80 | 70 | 80 |
| Context window | 10% | 61 | 44 | 32 |
| Overall | 100% | 66/100 | 54/100 | 55/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.6 SolOpenAI | GPT-5 ProOpenAI | Claude Opus 4.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 161.8 (best) | 150.3 | 150.1 |
| ECI rank | #8 of 148 (best) | #46 of 148 | #48 of 148 |
| GPQA DiamondGraduate-level science questions | 93.5% (best) | — | 86.1% |
| FrontierMath Tiers 1–3Research-level mathematics | 89.1% (best) | 55.8% | 34.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | — | 86.1% |
| SWE-bench VerifiedFixing real GitHub issues | — | — | 76.7% |
| SimpleQA VerifiedShort factual questions | 69.7% (best) | — | 45.7% |
| Price per million tokens | |||
| Input | $4.00 (best) | $15.00 | $5.00 |
| Output | $20.00 (best) | $120.00 | $25.00 |
| Cached input | $0.40 (best) | — | $0.50 |
| Blended (3:1) | $8.00 (best) | $41.25 | $10.00 |
| Long-context rate | Over 272K: $8.00 / $30.00 | Same rate | Same rate |
| Price source | Official OpenAI API | Official OpenAI API | Official Anthropic API |
| Limits | |||
| Context window | 1,050,000 tokens (best) | 400,000 tokens | 200,000 tokens |
| Max output | 128,000 tokens | 272,000 tokens (best) | 64,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeshigh | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gpt-5.6-sol | gpt-5-pro | claude-opus-4-5 |
| API providers | 40 (best) | 12 | 28 |
| Released | Jul 9, 2026 | Oct 6, 2025 | Nov 24, 2025 |
| Knowledge cutoff | Feb 16, 2026 | Sep 30, 2024 | 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 Sol$80.00
- GPT-5 Pro$390.00
- Claude Opus 4.5$100.00
Which should you choose?
Which is better: GPT-5.6 Sol, GPT-5 Pro or Claude Opus 4.5?
GPT-5.6 Sol is the better all-round choice, scoring 66/100 against Claude Opus 4.5 (55) and GPT-5 Pro (54). It leads on capability, price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.6 Sol, GPT-5 Pro or Claude Opus 4.5?
GPT-5.6 Sol is cheaper at $4.00 input / $20.00 output per million tokens (official OpenAI API price). Claude Opus 4.5 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price); GPT-5 Pro costs $15.00 input / $120.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $8.00 per million tokens for GPT-5.6 Sol versus $10.00 for Claude Opus 4.5 (1.3× as much) and $41.25 for GPT-5 Pro (5.2× as much).
Which scores higher on benchmarks?
GPT-5.6 Sol scores higher on the Capabilities Index (ECI): GPT-5.6 Sol 161.8 (#8 of 148), GPT-5 Pro 150.3 (#46 of 148) and Claude Opus 4.5 150.1 (#48 of 148). Their confidence ranges do not overlap (159.3–165.3 vs 148.5–152.8), so the gap is a real one. On individual benchmarks: FrontierMath Tiers 1–3 — GPT-5.6 Sol 89.1%, GPT-5 Pro 55.8%, Claude Opus 4.5 34.4%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.6 Sol and GPT-5 Pro yet, so there is no like-for-like coding score. On overall capability, GPT-5.6 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-5.6 Sol has the largest context window at 1,050,000 tokens, against 400,000 for GPT-5 Pro and 200,000 for Claude Opus 4.5. Maximum output per response: GPT-5.6 Sol up to 128,000, GPT-5 Pro up to 272,000, Claude Opus 4.5 up to 64,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.6 Sol accepts text, images and PDFs; GPT-5 Pro accepts text and images; Claude Opus 4.5 accepts text, images and PDFs. GPT-5.6 Sol handles the widest range of inputs.
Are any of these open source?
No. GPT-5.6 Sol, GPT-5 Pro and Claude Opus 4.5 are proprietary and only available through APIs and apps.
Which is newer?
GPT-5.6 Sol is the newest, released Jul 9, 2026. Claude Opus 4.5 came out Nov 24, 2025; GPT-5 Pro came out Oct 6, 2025. Knowledge cutoff: GPT-5.6 Sol Feb 16, 2026, GPT-5 Pro Sep 30, 2024, Claude Opus 4.5 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 Oct 4, 2026.
