Claude Sonnet 4.5 vs Gemini 3 Pro Preview vs o3
Gemini 3 Pro Preview comes out ahead, 67 to 58 and 55 on our weighted score, though o3 is 22% cheaper per token.
AnthropicClaude Sonnet 4.5
55/100- ECI146.8
- Price$3.00 / $15.00
- Context200K
- Our pick
GoogleGemini 3 Pro Preview
67/100- ECI153.0
- Price$2.00 / $12.00
- Context1.05M
OpenAIo3
58/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
Gemini 3 Pro Preview is our pick
Gemini 3 Pro Preview is the better all-round choice, scoring 67/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability, inputs & features and context window. o3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGemini 3 Pro PreviewCapabilities Index (ECI): Gemini 3 Pro Preview 153.0 · o3 146.9 · Claude Sonnet 4.5 146.8
- Lowest priceo3o3 $3.50 · Gemini 3 Pro Preview $4.50 · Claude Sonnet 4.5 $6.00 per 1M tokens (3:1 blend)
- Longest contextGemini 3 Pro PreviewGemini 3 Pro Preview 1,048,576 · Claude Sonnet 4.5 200,000 · o3 200,000 tokens
- Widest inputsGemini 3 Pro PreviewClaude Sonnet 4.5: Text, Images, PDFs · Gemini 3 Pro Preview: Text, Images, PDFs, Audio, Video · o3: Text, Images, PDFs
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Sonnet 4.5 | Gemini 3 Pro Preview | o3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 74 | 82 | 74 |
| Price | 25% | 13 | 19 | 24 |
| Inputs & features | 15% | 80 | 100 | 80 |
| Context window | 10% | 32 | 61 | 32 |
| Overall | 100% | 55/100 | 67/100 | 58/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 4.5Anthropic | Gemini 3 Pro PreviewGoogle | o3OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 146.8 | 153.0 (best) | 146.9 |
| ECI rank | #64 of 148 | #39 of 148 (best) | #63 of 148 |
| GPQA DiamondGraduate-level science questions | 82.3% | 92.6% (best) | 81.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 23.9% | — | 33.3% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 77.8% | 91.4% (best) | 84.4% |
| SWE-bench VerifiedFixing real GitHub issues | 71.3% | 72.9% (best) | 62.3% |
| SimpleQA VerifiedShort factual questions | 30.7% | — | 49.4% (best) |
| Price per million tokens | |||
| Input | $3.00 | $2.00 (best) | $2.00 (best) |
| Output | $15.00 | $12.00 | $8.00 (best) |
| Cached input | $0.30 (best) | — | $0.50 |
| Blended (3:1) | $6.00 | $4.50 | $3.50 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Median of 2 providers | Official OpenAI API |
| Limits | |||
| Context window | 200,000 tokens | 1,048,576 tokens (best) | 200,000 tokens |
| Max output | 64,000 tokens | 65,536 tokens | 100,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yes | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-sonnet-4-5 | — | o3 |
| API providers | 28 (best) | 3 | 18 |
| Released | Sep 29, 2025 | Nov 18, 2025 | Apr 16, 2025 |
| Knowledge cutoff | Jul 31, 2025 | Jan 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
- Gemini 3 Pro Preview$44.00
- o3$36.00
Which should you choose?
Which is better: Claude Sonnet 4.5, Gemini 3 Pro Preview or o3?
Gemini 3 Pro Preview is the better all-round choice, scoring 67/100 against o3 (58) and Claude Sonnet 4.5 (55). It leads on capability, inputs & features and context window. o3 wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 4.5, Gemini 3 Pro Preview or o3?
o3 is cheaper at $2.00 input / $8.00 output per million tokens (official OpenAI API price). Gemini 3 Pro Preview costs $2.00 input / $12.00 output per million tokens (median across 2 API providers); 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 $4.50 for Gemini 3 Pro Preview (1.3× as much) and $6.00 for Claude Sonnet 4.5 (1.7× as much).
Which scores higher on benchmarks?
Gemini 3 Pro Preview scores higher on the Capabilities Index (ECI): Gemini 3 Pro Preview 153.0 (#39 of 148), o3 146.9 (#63 of 148) and Claude Sonnet 4.5 146.8 (#64 of 148). Their confidence ranges do not overlap (150.6–155.2 vs 144.9–148.6), so the gap is a real one. On individual benchmarks: GPQA Diamond — Gemini 3 Pro Preview 92.6%, Claude Sonnet 4.5 82.3%, o3 81.8%; OTIS Mock AIME 2024–2025 — Gemini 3 Pro Preview 91.4%, o3 84.4%, Claude Sonnet 4.5 77.8%; SWE-bench Verified — Gemini 3 Pro Preview 72.9%, Claude Sonnet 4.5 71.3%, o3 62.3%.
Which is better for coding?
Gemini 3 Pro Preview resolves more real GitHub issues on SWE-bench Verified: Gemini 3 Pro Preview 72.9%, Claude Sonnet 4.5 71.3% and o3 62.3%. All three support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3 Pro Preview 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, Gemini 3 Pro Preview up to 65,536, o3 up to 100,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 4.5 accepts text, images and PDFs; Gemini 3 Pro Preview accepts text, images, PDFs, audio and video; o3 accepts text, images and PDFs. Gemini 3 Pro Preview handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 4.5, Gemini 3 Pro Preview and o3 are proprietary and only available through APIs and apps.
Which is newer?
Gemini 3 Pro Preview is the newest, released Nov 18, 2025. Claude Sonnet 4.5 came out Sep 29, 2025; o3 came out Apr 16, 2025. Knowledge cutoff: Claude Sonnet 4.5 Jul 31, 2025, Gemini 3 Pro Preview Jan 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.
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