Claude Sonnet 4.5 vs Inkling vs o3
Too close to call on our weighted score (Inkling 59, o3 58, Claude Sonnet 4.5 55). The right pick depends on what you value most.
AnthropicClaude Sonnet 4.5
55/100- ECI146.8
- Price$3.00 / $15.00
- Context200K
Thinking MachinesInkling
59/100- ECI148.6
- Price$3.74 / $9.36
- Context1.05M
OpenAIo3
58/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
Too close to call
It is close. Our weighted score puts them within a point (Inkling 59/100, o3 58/100, Claude Sonnet 4.5 55/100), so choose by what matters most for your work: Inkling for raw capability and o3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityInklingCapabilities Index (ECI): Inkling 148.6 · o3 146.9 · Claude Sonnet 4.5 146.8
- Lowest priceo3o3 $3.50 · Inkling $5.14 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
- Longest contextInklingInkling 1,048,576 · Claude Sonnet 4.5 200,000 · o3 200,000 tokens
- Widest inputsSame inputsClaude Sonnet 4.5: Text, Images, PDFs · Inkling: Text, Images, Audio · o3: Text, Images, PDFs
- Self-hostingInklingPublishes downloadable weights (Apache-2.0)
| Measure | Weight | Claude Sonnet 4.5 | Inkling | o3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 74 | 76 | 74 |
| Price | 25% | 13 | 16 | 24 |
| Inputs & features | 15% | 80 | 70 | 80 |
| Context window | 10% | 32 | 61 | 32 |
| Overall | 100% | 55/100 | 59/100 | 58/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 4.5Anthropic | InklingThinking Machines | o3OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 146.8 | 148.6 (best) | 146.9 |
| ECI rank | #64 of 148 | #57 of 148 (best) | #63 of 148 |
| GPQA DiamondGraduate-level science questions | 82.3% | 88.3% (best) | 81.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 23.9% | 33.3% (best) | 33.3% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 77.8% | 88.9% (best) | 84.4% |
| SWE-bench VerifiedFixing real GitHub issues | 71.3% (best) | — | 62.3% |
| SimpleQA VerifiedShort factual questions | 30.7% | 40.3% | 49.4% (best) |
| Price per million tokens | |||
| Input | $3.00 | $3.74 | $2.00 (best) |
| Output | $15.00 | $9.36 | $8.00 (best) |
| Cached input | $0.30 (best) | $0.748 | $0.50 |
| Blended (3:1) | $6.00 | $5.14 | $3.50 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Thinking Machines API | Official OpenAI API |
| Limits | |||
| Context window | 200,000 tokens | 1,048,576 tokens (best) | 200,000 tokens |
| Max output | 64,000 tokens | 1,048,576 tokens (best) | 100,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | No | Yes |
| Audio | No | Yes | No |
| Video | No | No | No |
| Reasoning | Yes | Yeslow · medium · high · xhigh · max | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | No | Yes |
| Availability | |||
| Weights | Proprietary | OpenApache-2.0 | Proprietary |
| API model ID | claude-sonnet-4-5 | thinkingmachines/Inkling:peft:262144 | o3 |
| API providers | 28 (best) | 23 | 18 |
| Released | Sep 29, 2025 | Jul 15, 2026 | Apr 16, 2025 |
| Knowledge cutoff | Jul 31, 2025 | — | May 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 Sonnet 4.5$60.00
- Inkling$56.12
- o3$36.00
Which should you choose?
Which is better: Claude Sonnet 4.5, Inkling or o3?
It is close. Our weighted score puts them within a point (Inkling 59/100, o3 58/100, Claude Sonnet 4.5 55/100), so choose by what matters most for your work: Inkling for raw capability and o3 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 4.5, Inkling or o3?
o3 is cheaper at $2.00 input / $8.00 output per million tokens (official OpenAI API price). Inkling costs $3.74 input / $9.36 output per million tokens (official Thinking Machines API price); Claude Sonnet 4.5 costs $3.00 input / $15.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $3.50 per million tokens for o3 versus $5.14 for Inkling (1.5× as much) and $6.00 for Claude Sonnet 4.5 (1.7× as much).
Which scores higher on benchmarks?
Inkling scores higher on the Capabilities Index (ECI): Inkling 148.6 (#57 of 148), o3 146.9 (#63 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). The confidence ranges of the top two overlap (145.7–150.6 vs 144.9–148.6), so treat the gap as small. On individual benchmarks: GPQA Diamond — Inkling 88.3%, Claude Sonnet 4.5 82.3%, o3 81.8%; FrontierMath Tiers 1–3 — Inkling 33.3%, o3 33.3%, Claude Sonnet 4.5 23.9%; OTIS Mock AIME 2024–2025 — Inkling 88.9%, o3 84.4%, Claude Sonnet 4.5 77.8%; SimpleQA Verified — o3 49.4%, Inkling 40.3%, Claude Sonnet 4.5 30.7%.
Which is better for coding?
There are no published SWE-bench Verified results for Inkling yet, so there is no like-for-like coding score. On overall capability, Inkling 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?
Inkling has the largest context window at 1,048,576 tokens, against 200,000 for Claude Sonnet 4.5 and 200,000 for o3. Maximum output per response: Claude Sonnet 4.5 up to 64,000, Inkling up to 1,048,576, o3 up to 100,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 4.5 accepts text, images and PDFs; Inkling accepts text, images and audio; o3 accepts text, images and PDFs. They handle the same number of input types.
Are any of these open source?
Inkling publishes its weights (Apache-2.0) and can be self-hosted; Claude Sonnet 4.5 and o3 is proprietary.
Which is newer?
Inkling is the newest, released Jul 15, 2026. Claude Sonnet 4.5 came out Sep 29, 2025; o3 came out Apr 16, 2025. Knowledge cutoff: Claude Sonnet 4.5 Jul 31, 2025, o3 May 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.
