Claude Opus 5.5 vs Inkling Small
Too close to call on our weighted score (Claude Opus 5.5 69, Inkling Small 68). The right pick depends on what you value most.
AnthropicClaude Opus 5.5
69/100- ECI168.4
- Price$4.00 / $20.00
- Context1M
Thinking MachinesInkling Small
68/100- ECI150.5
- Price$0.58 / $1.44
- Context1.05M
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Make it a three-way comparison.
Too close to call
It is close. Our weighted score puts them within 1 points (Claude Opus 5.5 69/100, Inkling Small 68/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability, Inkling Small on price and Inkling Small for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Opus 5.5Capabilities Index (ECI): Claude Opus 5.5 168.4 · Inkling Small 150.5
- Lowest priceInkling SmallInkling Small $0.795 · Claude Opus 5.5 $8.00 per 1M tokens (3:1 blend)
- Longest contextInkling SmallInkling Small 1,048,576 · Claude Opus 5.5 1,000,000 tokens
- Widest inputsSame inputsClaude Opus 5.5: Text, Images, PDFs · Inkling Small: Text, Images, Audio
- Self-hostingInkling SmallPublishes downloadable weights (Apache-2.0)
| Measure | Weight | Claude Opus 5.5 | Inkling Small |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 99 | 77 |
| Price | 25% | 7 | 52 |
| Inputs & features | 15% | 80 | 70 |
| Context window | 10% | 60 | 61 |
| Overall | 100% | 69/100 | 68/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Opus 5.5Anthropic | Inkling SmallThinking Machines |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 168.4 (best) | 150.5 |
| ECI rank | #2 of 165 (best) | #58 of 165 |
| GPQA DiamondGraduate-level science questions | 90.6% (best) | 88.5% |
| FrontierMath Tiers 1–3Research-level mathematics | 91.2% (best) | 46.3% |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% (best) | 90.0% |
| SimpleQA VerifiedShort factual questions | 72.2% (best) | 19.1% |
| Price per million tokens | ||
| Input | $4.00 | $0.58 (best) |
| Output | $20.00 | $1.44 (best) |
| Cached input | $0.20 | $0.116 (best) |
| Blended (3:1) | $8.00 | $0.795 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Thinking Machines API |
| Limits | ||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) |
| Max output | 128,000 tokens | 1,048,576 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | No |
| Audio | No | Yes |
| Video | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | No |
| Availability | ||
| Weights | Proprietary | OpenApache-2.0 |
| API model ID | claude-opus-5-5 | thinkingmachines/Inkling-Small |
| API providers | 36 (best) | 12 |
| Released | Sep 22, 2026 | Jul 30, 2026 |
| Knowledge cutoff | Jun 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 5.5$80.00
- Inkling Small$8.68
Which should you choose?
Which is better: Claude Opus 5.5 or Inkling Small?
It is close. Our weighted score puts them within 1 points (Claude Opus 5.5 69/100, Inkling Small 68/100), so choose by what matters most for your work: Claude Opus 5.5 for raw capability, Inkling Small on price and Inkling Small for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Opus 5.5 or Inkling Small?
Inkling Small is cheaper at $0.58 input / $1.44 output per million tokens (official Thinking Machines API price). Claude Opus 5.5 costs $4.00 input / $20.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.795 per million tokens for Inkling Small versus $8.00 for Claude Opus 5.5 (10× as much).
Which scores higher on benchmarks?
Claude Opus 5.5 scores higher on the Capabilities Index (ECI): Claude Opus 5.5 168.4 (#2 of 165) and Inkling Small 150.5 (#58 of 165). Their confidence ranges do not overlap (165.4–173.0 vs 147.7–152.4), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Opus 5.5 90.6%, Inkling Small 88.5%; FrontierMath Tiers 1–3 — Claude Opus 5.5 91.2%, Inkling Small 46.3%; OTIS Mock AIME 2024–2025 — Claude Opus 5.5 100%, Inkling Small 90.0%; SimpleQA Verified — Claude Opus 5.5 72.2%, Inkling Small 19.1%.
Which is better for coding?
There are no published SWE-bench Verified results for Claude Opus 5.5 and Inkling Small yet, so there is no like-for-like coding score. On overall capability, Claude Opus 5.5 leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.
Which has the bigger context window?
Inkling Small has the largest context window at 1,048,576 tokens, against 1,000,000 for Claude Opus 5.5. Maximum output per response: Claude Opus 5.5 up to 128,000, Inkling Small up to 1,048,576 tokens.
Which can read images, PDFs, audio or video?
Claude Opus 5.5 accepts text, images and PDFs; Inkling Small accepts text, images and audio. They handle the same number of input types.
Are any of these open source?
Inkling Small publishes its weights (Apache-2.0) and can be self-hosted; Claude Opus 5.5 is proprietary.
Which is newer?
Claude Opus 5.5 is the newest, released Sep 22, 2026. Inkling Small came out Jul 30, 2026. Knowledge cutoff: Claude Opus 5.5 Jun 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 Nov 2, 2026.
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