GPT-5.1 vs o3-pro vs Claude Opus 4.5
GPT-5.1 comes out ahead, 60 to 55 and 51 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-5.1
60/100- ECI149.7
- Price$1.25 / $10.00
- Context400K
- OpenAI
o3-pro
51/100- ECI147.4
- Price$20.00 / $80.00
- Context200K
AnthropicClaude Opus 4.5
55/100- ECI150.1
- Price$5.00 / $25.00
- Context200K
GPT-5.1 is our pick
GPT-5.1 is the better all-round choice, scoring 60/100 against Claude Opus 4.5 (55) and o3-pro (51). It leads on price and context window. Claude Opus 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 4.5Capabilities Index (ECI): Claude Opus 4.5 150.1 · GPT-5.1 149.7 · o3-pro 147.4
- Lowest priceGPT-5.1GPT-5.1 $3.44 · Claude Opus 4.5 $10.00 · o3-pro $35.00 per 1M tokens (3:1 blend)
- Longest contextGPT-5.1GPT-5.1 400,000 · o3-pro 200,000 · Claude Opus 4.5 200,000 tokens
- Widest inputsClaude Opus 4.5GPT-5.1: Text, Images · o3-pro: Text, Images · Claude Opus 4.5: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-5.1 | o3-pro | Claude Opus 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 78 | 75 | 78 |
| Price | 25% | 24 | 0 | 2 |
| Inputs & features | 15% | 70 | 70 | 80 |
| Context window | 10% | 44 | 32 | 32 |
| Overall | 100% | 60/100 | 51/100 | 55/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.1OpenAI | o3-proOpenAI | Claude Opus 4.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 149.7 | 147.4 | 150.1 (best) |
| ECI rank | #52 of 148 | #60 of 148 | #48 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 87.6% (best) | — | 86.1% |
| FrontierMath Tiers 1–3Research-level mathematics | — | — | 34.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 88.6% (best) | — | 86.1% |
| SWE-bench VerifiedFixing real GitHub issues | 68.0% | — | 76.7% (best) |
| SimpleQA VerifiedShort factual questions | 48.0% (best) | — | 45.7% |
| Price per million tokens | |||
| Input | $1.25 (best) | $20.00 | $5.00 |
| Output | $10.00 (best) | $80.00 | $25.00 |
| Cached input | $0.125 (best) | — | $0.50 |
| Blended (3:1) | $3.44 (best) | $35.00 | $10.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official OpenAI API | Official OpenAI API | Official Anthropic API |
| Limits | |||
| Context window | 400,000 tokens (best) | 200,000 tokens | 200,000 tokens |
| Max output | 128,000 tokens (best) | 100,000 tokens | 64,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | No | No | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high | Yeslow · medium · high | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gpt-5.1 | o3-pro | claude-opus-4-5 |
| API providers | 21 | 6 | 28 (best) |
| Released | Nov 13, 2025 | Jun 10, 2025 | Nov 24, 2025 |
| Knowledge cutoff | Sep 30, 2024 | May 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-5.1$32.50
- o3-pro$360.00
- Claude Opus 4.5$100.00
Which should you choose?
Which is better: GPT-5.1, o3-pro or Claude Opus 4.5?
GPT-5.1 is the better all-round choice, scoring 60/100 against Claude Opus 4.5 (55) and o3-pro (51). It leads on price and context window. Claude Opus 4.5 wins on inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.1, o3-pro or Claude Opus 4.5?
GPT-5.1 is cheaper at $1.25 input / $10.00 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); o3-pro costs $20.00 input / $80.00 output per million tokens (official OpenAI 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 $10.00 for Claude Opus 4.5 (2.9× as much) and $35.00 for o3-pro (10× as much).
Which scores higher on benchmarks?
Claude Opus 4.5 scores higher on the Capabilities Index (ECI): Claude Opus 4.5 150.1 (#48 of 148), GPT-5.1 149.7 (#52 of 148) and o3-pro 147.4 (#60 of 148). The confidence ranges of the top two overlap (147.9–153.0 vs 148.3–151.1), so treat the gap as small.
Which is better for coding?
There are no published SWE-bench Verified results for o3-pro yet, so there is no like-for-like coding score. On overall capability, Claude Opus 4.5 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-5.1 has the largest context window at 400,000 tokens, against 200,000 for o3-pro and 200,000 for Claude Opus 4.5. Maximum output per response: GPT-5.1 up to 128,000, o3-pro up to 100,000, Claude Opus 4.5 up to 64,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.1 accepts text and images; o3-pro accepts text and images; Claude Opus 4.5 accepts text, images and PDFs. Claude Opus 4.5 handles the widest range of inputs.
Are any of these open source?
No. GPT-5.1, o3-pro and Claude Opus 4.5 are proprietary and only available through APIs and apps.
Which is newer?
Claude Opus 4.5 is the newest, released Nov 24, 2025. GPT-5.1 came out Nov 13, 2025; o3-pro came out Jun 10, 2025. Knowledge cutoff: GPT-5.1 Sep 30, 2024, o3-pro May 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.
