o3-pro vs Claude Sonnet 3.5 v2
o3-pro comes out ahead, 51 to 44 on our weighted score, though Claude Sonnet 3.5 v2 is 5.8× cheaper per token.
- Our pick
OpenAIo3-pro
51/100- ECI147.4
- Price$20.00 / $80.00
- Context200K
AnthropicClaude Sonnet 3.5 v2
44/100- ECI133.5
- Price$3.00 / $15.00
- Context200K
Add a model
Make it a three-way comparison.
o3-pro is our pick
o3-pro is the better all-round choice, scoring 51/100 against Claude Sonnet 3.5 v2 (44). It leads on capability and inputs & features. Claude Sonnet 3.5 v2 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- Capabilityo3-proCapabilities Index (ECI): o3-pro 147.4 · Claude Sonnet 3.5 v2 133.5
- Lowest priceClaude Sonnet 3.5 v2Claude Sonnet 3.5 v2 $6.00 · o3-pro $35.00 per 1M tokens (3:1 blend)
- Longest contextAbout the sameo3-pro 200,000 · Claude Sonnet 3.5 v2 200,000 tokens
- Widest inputsClaude Sonnet 3.5 v2o3-pro: Text, Images · Claude Sonnet 3.5 v2: Text, Images, PDFs
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | o3-pro | Claude Sonnet 3.5 v2 |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 75 | 57 |
| Price | 25% | 0 | 13 |
| Inputs & features | 15% | 70 | 60 |
| Context window | 10% | 32 | 32 |
| Overall | 100% | 51/100 | 44/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | o3-proOpenAI | Claude Sonnet 3.5 v2Anthropic |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 147.4 (best) | 133.5 |
| ECI rank | #60 of 148 (best) | #119 of 148 |
| GPQA DiamondGraduate-level science questions | — | 55.3% |
| OTIS Mock AIME 2024–2025Competition mathematics | — | 8.5% |
| Price per million tokens | ||
| Input | $20.00 | $3.00 (best) |
| Output | $80.00 | $15.00 (best) |
| Cached input | — | — |
| Blended (3:1) | $35.00 | $6.00 (best) |
| Long-context rate | Same rate | Same rate |
| Price source | Official OpenAI API | Median of 1 providers |
| Limits | ||
| Context window | 200,000 tokens | 200,000 tokens |
| Max output | 100,000 tokens (best) | 8,192 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | Yes |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high | No |
| Tool calling | Yes | Yes |
| Structured output | Yes | No |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | o3-pro | — |
| API providers | 6 (best) | 1 |
| Released | Jun 10, 2025 | Oct 22, 2024 |
| Knowledge cutoff | May 2024 | Apr 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.
- o3-pro$360.00
- Claude Sonnet 3.5 v2$60.00
Which should you choose?
Which is better: o3-pro or Claude Sonnet 3.5 v2?
o3-pro is the better all-round choice, scoring 51/100 against Claude Sonnet 3.5 v2 (44). It leads on capability and inputs & features. Claude Sonnet 3.5 v2 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, o3-pro or Claude Sonnet 3.5 v2?
Claude Sonnet 3.5 v2 is cheaper at $3.00 input / $15.00 output per million tokens (median across 1 API provider). 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 $6.00 per million tokens for Claude Sonnet 3.5 v2 versus $35.00 for o3-pro (5.8× as much).
Which scores higher on benchmarks?
o3-pro scores higher on the Capabilities Index (ECI): o3-pro 147.4 (#60 of 148) and Claude Sonnet 3.5 v2 133.5 (#119 of 148). Their confidence ranges do not overlap (145.8–149.7 vs 129.2–137.5), so the gap is a real one.
Which is better for coding?
There are no published SWE-bench Verified results for o3-pro and Claude Sonnet 3.5 v2 yet, so there is no like-for-like coding score. On overall capability, o3-pro 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?
o3-pro and Claude Sonnet 3.5 v2 share the same 200,000-token context window. Maximum output per response: o3-pro up to 100,000, Claude Sonnet 3.5 v2 up to 8,192 tokens.
Which can read images, PDFs, audio or video?
o3-pro accepts text and images; Claude Sonnet 3.5 v2 accepts text, images and PDFs. Claude Sonnet 3.5 v2 handles the widest range of inputs.
Are any of these open source?
No. o3-pro and Claude Sonnet 3.5 v2 are proprietary and only available through APIs and apps.
Which is newer?
o3-pro is the newest, released Jun 10, 2025. Claude Sonnet 3.5 v2 came out Oct 22, 2024. Knowledge cutoff: o3-pro May 2024, Claude Sonnet 3.5 v2 Apr 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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