Claude Opus 4.5 vs Kimi K2.7 Code vs GPT-5.1
Kimi K2.7 Code comes out ahead, 64 to 60 and 55 on our weighted score, and it is the cheaper option too.
AnthropicClaude Opus 4.5
55/100- ECI150.1
- Price$5.00 / $25.00
- Context200K
- Our pick
Moonshot AIKimi K2.7 Code
64/100- ECI150.0
- Price$0.95 / $4.00
- Context262K
OpenAIGPT-5.1
60/100- ECI149.7
- Price$1.25 / $10.00
- Context400K
Kimi K2.7 Code is our pick
Kimi K2.7 Code is the better all-round choice, scoring 64/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on price. GPT-5.1 wins on 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 · Kimi K2.7 Code 150.0 · GPT-5.1 149.7
- Lowest priceKimi K2.7 CodeKimi K2.7 Code $1.71 · GPT-5.1 $3.44 · Claude Opus 4.5 $10.00 per 1M tokens (3:1 blend)
- Longest contextGPT-5.1GPT-5.1 400,000 · Kimi K2.7 Code 262,144 · Claude Opus 4.5 200,000 tokens
- Widest inputsClaude Opus 4.5 and Kimi K2.7 CodeClaude Opus 4.5: Text, Images, PDFs · Kimi K2.7 Code: Text, Images, Video · GPT-5.1: Text, Images
- Self-hostingKimi K2.7 CodePublishes downloadable weights
| Measure | Weight | Claude Opus 4.5 | Kimi K2.7 Code | GPT-5.1 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 78 | 78 | 78 |
| Price | 25% | 2 | 39 | 24 |
| Inputs & features | 15% | 80 | 80 | 70 |
| Context window | 10% | 32 | 37 | 44 |
| Overall | 100% | 55/100 | 64/100 | 60/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Opus 4.5Anthropic | Kimi K2.7 CodeMoonshot AI | GPT-5.1OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 150.1 (best) | 150.0 | 149.7 |
| ECI rank | #48 of 148 (best) | #49 of 148 | #52 of 148 |
| GPQA DiamondGraduate-level science questions | 86.1% | 87.9% (best) | 87.6% |
| FrontierMath Tiers 1–3Research-level mathematics | 34.4% | 54.0% (best) | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 86.1% | 95.6% (best) | 88.6% |
| SWE-bench VerifiedFixing real GitHub issues | 76.7% (best) | — | 68.0% |
| SimpleQA VerifiedShort factual questions | 45.7% | 36.5% | 48.0% (best) |
| Price per million tokens | |||
| Input | $5.00 | $0.95 (best) | $1.25 |
| Output | $25.00 | $4.00 (best) | $10.00 |
| Cached input | $0.50 | $0.19 | $0.125 (best) |
| Blended (3:1) | $10.00 | $1.71 (best) | $3.44 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Moonshot AI API | Official OpenAI API |
| Limits | |||
| Context window | 200,000 tokens | 262,144 tokens | 400,000 tokens (best) |
| Max output | 64,000 tokens | 262,144 tokens (best) | 128,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | No |
| Audio | No | No | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · medium · high | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Open | Proprietary |
| API model ID | claude-opus-4-5 | kimi-k2.7-code | gpt-5.1 |
| API providers | 28 | 51 (best) | 21 |
| Released | Nov 24, 2025 | Jun 12, 2026 | Nov 13, 2025 |
| Knowledge cutoff | May 2025 | Jan 2025 | Sep 30, 2024 |
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 4.5$100.00
- Kimi K2.7 Code$17.50
- GPT-5.1$32.50
Which should you choose?
Which is better: Claude Opus 4.5, Kimi K2.7 Code or GPT-5.1?
Kimi K2.7 Code is the better all-round choice, scoring 64/100 against GPT-5.1 (60) and Claude Opus 4.5 (55). It leads on price. GPT-5.1 wins on context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Opus 4.5, Kimi K2.7 Code or GPT-5.1?
Kimi K2.7 Code is cheaper at $0.95 input / $4.00 output per million tokens (official Moonshot AI 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 $1.71 per million tokens for Kimi K2.7 Code versus $3.44 for GPT-5.1 (2× as much) and $10.00 for Claude Opus 4.5 (5.8× 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), Kimi K2.7 Code 150.0 (#49 of 148) and GPT-5.1 149.7 (#52 of 148). The confidence ranges of the top two overlap (147.9–153.0 vs 148.1–151.8), so treat the gap as small. On individual benchmarks: GPQA Diamond — Kimi K2.7 Code 87.9%, GPT-5.1 87.6%, Claude Opus 4.5 86.1%; OTIS Mock AIME 2024–2025 — Kimi K2.7 Code 95.6%, GPT-5.1 88.6%, Claude Opus 4.5 86.1%; SimpleQA Verified — GPT-5.1 48.0%, Claude Opus 4.5 45.7%, Kimi K2.7 Code 36.5%.
Which is better for coding?
There are no published SWE-bench Verified results for Kimi K2.7 Code 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 262,144 for Kimi K2.7 Code and 200,000 for Claude Opus 4.5. Maximum output per response: Claude Opus 4.5 up to 64,000, Kimi K2.7 Code up to 262,144, GPT-5.1 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Opus 4.5 accepts text, images and PDFs; Kimi K2.7 Code accepts text, images and video; GPT-5.1 accepts text and images. Claude Opus 4.5 handles the widest range of inputs.
Are any of these open source?
Kimi K2.7 Code publishes its weights and can be self-hosted; Claude Opus 4.5 and GPT-5.1 is proprietary.
Which is newer?
Kimi K2.7 Code is the newest, released Jun 12, 2026. Claude Opus 4.5 came out Nov 24, 2025; GPT-5.1 came out Nov 13, 2025. Knowledge cutoff: Claude Opus 4.5 May 2025, Kimi K2.7 Code Jan 2025, GPT-5.1 Sep 30, 2024.
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.
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