o3 vs Claude Sonnet 4.5 vs Claude Sonnet 4.6
Claude Sonnet 4.6 comes out ahead, 62 to 58 and 55 on our weighted score, though o3 is 42% cheaper per token.
OpenAIo3
58/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
AnthropicClaude Sonnet 4.5
55/100- ECI146.8
- Price$3.00 / $15.00
- Context200K
- Our pickAnthropic
Claude Sonnet 4.6
62/100- ECI152.3
- Price$3.00 / $15.00
- Context1M
Claude Sonnet 4.6 is our pick
Claude Sonnet 4.6 is the better all-round choice, scoring 62/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability and context window. o3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityClaude Sonnet 4.6Capabilities Index (ECI): Claude Sonnet 4.6 152.3 · o3 146.9 · Claude Sonnet 4.5 146.8
- Lowest priceo3o3 $3.50 · Claude Sonnet 4.5 $6.00 · Claude Sonnet 4.6 $6.00 per 1M tokens (3:1 blend)
- Longest contextClaude Sonnet 4.6Claude Sonnet 4.6 1,000,000 · o3 200,000 · Claude Sonnet 4.5 200,000 tokens
- Widest inputsSame inputso3: Text, Images, PDFs · Claude Sonnet 4.5: Text, Images, PDFs · Claude Sonnet 4.6: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | o3 | Claude Sonnet 4.5 | Claude Sonnet 4.6 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 74 | 74 | 81 |
| Price | 25% | 24 | 13 | 13 |
| Inputs & features | 15% | 80 | 80 | 80 |
| Context window | 10% | 32 | 32 | 60 |
| Overall | 100% | 58/100 | 55/100 | 62/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | o3OpenAI | Claude Sonnet 4.5Anthropic | Claude Sonnet 4.6Anthropic |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 146.9 | 146.8 | 152.3 (best) |
| ECI rank | #63 of 148 | #64 of 148 | #40 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 81.8% | 82.3% | 87.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 33.3% (best) | 23.9% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 84.4% | 77.8% | 85.8% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 62.3% | 71.3% | 75.2% (best) |
| SimpleQA VerifiedShort factual questions | 49.4% (best) | 30.7% | 35.5% |
| Price per million tokens | |||
| Input | $2.00 (best) | $3.00 | $3.00 |
| Output | $8.00 (best) | $15.00 | $15.00 |
| Cached input | $0.50 | $0.30 (best) | $0.30 (best) |
| Blended (3:1) | $3.50 (best) | $6.00 | $6.00 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official OpenAI API | Official Anthropic API | Official Anthropic API |
| Limits | |||
| Context window | 200,000 tokens | 200,000 tokens | 1,000,000 tokens (best) |
| Max output | 100,000 tokens (best) | 64,000 tokens | 64,000 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high | Yes | Yeslow · medium · high · max |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | o3 | claude-sonnet-4-5 | claude-sonnet-4-6 |
| API providers | 18 | 28 | 41 (best) |
| Released | Apr 16, 2025 | Sep 29, 2025 | Feb 17, 2026 |
| Knowledge cutoff | May 2024 | Jul 31, 2025 | Aug 31, 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- o3$36.00
- Claude Sonnet 4.5$60.00
- Claude Sonnet 4.6$60.00
Which should you choose?
Which is better: o3, Claude Sonnet 4.5 or Claude Sonnet 4.6?
Claude Sonnet 4.6 is the better all-round choice, scoring 62/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability and context window. o3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, o3, Claude Sonnet 4.5 or Claude Sonnet 4.6?
o3 is cheaper at $2.00 input / $8.00 output per million tokens (official OpenAI API price). Claude Sonnet 4.5 costs $3.00 input / $15.00 output per million tokens (official Anthropic API price); Claude Sonnet 4.6 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 $6.00 for Claude Sonnet 4.5 (1.7× as much) and $6.00 for Claude Sonnet 4.6 (1.7× as much).
Which scores higher on benchmarks?
Claude Sonnet 4.6 scores higher on the Capabilities Index (ECI): Claude Sonnet 4.6 152.3 (#40 of 148), o3 146.9 (#63 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). Their confidence ranges do not overlap (149.6–154.7 vs 144.9–148.6), so the gap is a real one. On individual benchmarks: GPQA Diamond — Claude Sonnet 4.6 87.4%, Claude Sonnet 4.5 82.3%, o3 81.8%; OTIS Mock AIME 2024–2025 — Claude Sonnet 4.6 85.8%, o3 84.4%, Claude Sonnet 4.5 77.8%; SWE-bench Verified — Claude Sonnet 4.6 75.2%, Claude Sonnet 4.5 71.3%, o3 62.3%; SimpleQA Verified — o3 49.4%, Claude Sonnet 4.6 35.5%, Claude Sonnet 4.5 30.7%.
Which is better for coding?
Claude Sonnet 4.6 resolves more real GitHub issues on SWE-bench Verified: Claude Sonnet 4.6 75.2%, Claude Sonnet 4.5 71.3% and o3 62.3%. All three support tool calling for agent workflows.
Which has the bigger context window?
Claude Sonnet 4.6 has the largest context window at 1,000,000 tokens, against 200,000 for o3 and 200,000 for Claude Sonnet 4.5. Maximum output per response: o3 up to 100,000, Claude Sonnet 4.5 up to 64,000, Claude Sonnet 4.6 up to 64,000 tokens.
Which can read images, PDFs, audio or video?
o3 accepts text, images and PDFs; Claude Sonnet 4.5 accepts text, images and PDFs; Claude Sonnet 4.6 accepts text, images and PDFs. They handle the same number of input types.
Are any of these open source?
No. o3, Claude Sonnet 4.5 and Claude Sonnet 4.6 are proprietary and only available through APIs and apps.
Which is newer?
Claude Sonnet 4.6 is the newest, released Feb 17, 2026. Claude Sonnet 4.5 came out Sep 29, 2025; o3 came out Apr 16, 2025. Knowledge cutoff: o3 May 2024, Claude Sonnet 4.5 Jul 31, 2025, Claude Sonnet 4.6 Aug 31, 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.
