GPT-5.1 vs Grok 4.3 vs Claude Opus 4.5
Grok 4.3 comes out ahead, 67 to 60 and 55 on our weighted score, and it is the cheaper option too.
OpenAIGPT-5.1
60/100- ECI149.7
- Price$1.25 / $10.00
- Context400K
- Our pick
xAIGrok 4.3
67/100- ECI149.2
- Price$1.25 / $2.50
- Context1M
AnthropicClaude Opus 4.5
55/100- ECI150.1
- Price$5.00 / $25.00
- Context200K
Grok 4.3 is our pick
Grok 4.3 is the better all-round choice, scoring 67/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on price and context window. 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 · Grok 4.3 149.2
- Lowest priceGrok 4.3Grok 4.3 $1.56 · GPT-5.1 $3.44 · Claude Opus 4.5 $10.00 per 1M tokens (3:1 blend)
- Longest contextGrok 4.3Grok 4.3 1,000,000 · GPT-5.1 400,000 · Claude Opus 4.5 200,000 tokens
- Widest inputsGrok 4.3 and Claude Opus 4.5GPT-5.1: Text, Images · Grok 4.3: Text, Images, PDFs · Claude Opus 4.5: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | GPT-5.1 | Grok 4.3 | Claude Opus 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 78 | 77 | 78 |
| Price | 25% | 24 | 41 | 2 |
| Inputs & features | 15% | 70 | 80 | 80 |
| Context window | 10% | 44 | 60 | 32 |
| Overall | 100% | 60/100 | 67/100 | 55/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.1OpenAI | Grok 4.3xAI | Claude Opus 4.5Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 149.7 | 149.2 | 150.1 (best) |
| ECI rank | #52 of 148 | #55 of 148 | #48 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 87.6% | 88.8% (best) | 86.1% |
| FrontierMath Tiers 1–3Research-level mathematics | — | 42.8% (best) | 34.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 88.6% | 93.3% (best) | 86.1% |
| SWE-bench VerifiedFixing real GitHub issues | 68.0% | — | 76.7% (best) |
| SimpleQA VerifiedShort factual questions | 48.0% (best) | 33.2% | 45.7% |
| Price per million tokens | |||
| Input | $1.25 (best) | $1.25 (best) | $5.00 |
| Output | $10.00 | $2.50 (best) | $25.00 |
| Cached input | $0.125 (best) | $0.20 | $0.50 |
| Blended (3:1) | $3.44 | $1.56 (best) | $10.00 |
| Long-context rate | Same rate | Over 200K: $2.50 / $5.00 | Same rate |
| Price source | Official OpenAI API | Official xAI API | Official Anthropic API |
| Limits | |||
| Context window | 400,000 tokens | 1,000,000 tokens (best) | 200,000 tokens |
| Max output | 128,000 tokens (best) | 30,000 tokens | 64,000 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 | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gpt-5.1 | grok-4.3 | claude-opus-4-5 |
| API providers | 21 | 27 | 28 (best) |
| Released | Nov 13, 2025 | Apr 17, 2026 | Nov 24, 2025 |
| Knowledge cutoff | 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-5.1$32.50
- Grok 4.3$17.50
- Claude Opus 4.5$100.00
Which should you choose?
Which is better: GPT-5.1, Grok 4.3 or Claude Opus 4.5?
Grok 4.3 is the better all-round choice, scoring 67/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5.1, Grok 4.3 or Claude Opus 4.5?
Grok 4.3 is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). GPT-5.1 costs $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). At a typical mix of three input tokens to one output token, that is $1.56 per million tokens for Grok 4.3 versus $3.44 for GPT-5.1 (2.2× as much) and $10.00 for Claude Opus 4.5 (6.4× 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 Grok 4.3 149.2 (#55 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. On individual benchmarks: GPQA Diamond — Grok 4.3 88.8%, GPT-5.1 87.6%, Claude Opus 4.5 86.1%; OTIS Mock AIME 2024–2025 — Grok 4.3 93.3%, GPT-5.1 88.6%, Claude Opus 4.5 86.1%; SimpleQA Verified — GPT-5.1 48.0%, Claude Opus 4.5 45.7%, Grok 4.3 33.2%.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4.3 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?
Grok 4.3 has the largest context window at 1,000,000 tokens, against 400,000 for GPT-5.1 and 200,000 for Claude Opus 4.5. Maximum output per response: GPT-5.1 up to 128,000, Grok 4.3 up to 30,000, Claude Opus 4.5 up to 64,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.1 accepts text and images; Grok 4.3 accepts text, images and PDFs; Claude Opus 4.5 accepts text, images and PDFs. Grok 4.3 handles the widest range of inputs.
Are any of these open source?
No. GPT-5.1, Grok 4.3 and Claude Opus 4.5 are proprietary and only available through APIs and apps.
Which is newer?
Grok 4.3 is the newest, released Apr 17, 2026. Claude Opus 4.5 came out Nov 24, 2025; GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: GPT-5.1 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.
