Gemini 2.5 Pro vs Gemini 3 Pro Preview vs o3
Gemini 3 Pro Preview comes out ahead, 67 to 63 and 58 on our weighted score, though Gemini 2.5 Pro is 24% cheaper per token.
GoogleGemini 2.5 Pro
63/100- ECI145.3
- Price$1.25 / $10.00
- Context1.05M
- Our pickGoogle
Gemini 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 Gemini 2.5 Pro (63) and o3 (58). It leads on capability. 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 · Gemini 2.5 Pro 145.3
- Lowest priceGemini 2.5 ProGemini 2.5 Pro $3.44 · o3 $3.50 · Gemini 3 Pro Preview $4.50 per 1M tokens (3:1 blend)
- Longest contextGemini 2.5 Pro and Gemini 3 Pro PreviewGemini 2.5 Pro 1,048,576 · Gemini 3 Pro Preview 1,048,576 · o3 200,000 tokens
- Widest inputsGemini 2.5 Pro and Gemini 3 Pro PreviewGemini 2.5 Pro: Text, Images, PDFs, Audio, Video · 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 | Gemini 2.5 Pro | Gemini 3 Pro Preview | o3 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 72 | 82 | 74 |
| Price | 25% | 24 | 19 | 24 |
| Inputs & features | 15% | 100 | 100 | 80 |
| Context window | 10% | 61 | 61 | 32 |
| Overall | 100% | 63/100 | 67/100 | 58/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Gemini 2.5 ProGoogle | Gemini 3 Pro PreviewGoogle | o3OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 145.3 | 153.0 (best) | 146.9 |
| ECI rank | #78 of 148 | #39 of 148 (best) | #63 of 148 |
| GPQA DiamondGraduate-level science questions | 85.3% | 92.6% (best) | 81.8% |
| FrontierMath Tiers 1–3Research-level mathematics | 24.6% | — | 33.3% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 84.7% | 91.4% (best) | 84.4% |
| SWE-bench VerifiedFixing real GitHub issues | 57.6% | 72.9% (best) | 62.3% |
| SimpleQA VerifiedShort factual questions | — | — | 49.4% |
| Price per million tokens | |||
| Input | $1.25 (best) | $2.00 | $2.00 |
| Output | $10.00 | $12.00 | $8.00 (best) |
| Cached input | $0.125 (best) | — | $0.50 |
| Blended (3:1) | $3.44 (best) | $4.50 | $3.50 |
| Long-context rate | Over 200K: $2.50 / $15.00 | Same rate | Same rate |
| Price source | Official Google API | Median of 2 providers | Official OpenAI API |
| Limits | |||
| Context window | 1,048,576 tokens (best) | 1,048,576 tokens (best) | 200,000 tokens |
| Max output | 65,536 tokens | 65,536 tokens | 100,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | Yes | Yes | No |
| Video | Yes | 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 | gemini-2.5-pro | — | o3 |
| API providers | 22 (best) | 3 | 18 |
| Released | Jun 17, 2025 | Nov 18, 2025 | Apr 16, 2025 |
| Knowledge cutoff | Jan 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.
- Gemini 2.5 Pro$32.50
- Gemini 3 Pro Preview$44.00
- o3$36.00
Which should you choose?
Which is better: Gemini 2.5 Pro, Gemini 3 Pro Preview or o3?
Gemini 3 Pro Preview is the better all-round choice, scoring 67/100 against Gemini 2.5 Pro (63) and o3 (58). It leads on capability. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Gemini 2.5 Pro, Gemini 3 Pro Preview or o3?
Gemini 2.5 Pro is cheaper at $1.25 input / $10.00 output per million tokens (official Google API price). o3 costs $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). At a typical mix of three input tokens to one output token, that is $3.44 per million tokens for Gemini 2.5 Pro versus $3.50 for o3 (1× as much) and $4.50 for Gemini 3 Pro Preview (1.3× 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 Gemini 2.5 Pro 145.3 (#78 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%, Gemini 2.5 Pro 85.3%, o3 81.8%; OTIS Mock AIME 2024–2025 — Gemini 3 Pro Preview 91.4%, Gemini 2.5 Pro 84.7%, o3 84.4%; SWE-bench Verified — Gemini 3 Pro Preview 72.9%, o3 62.3%, Gemini 2.5 Pro 57.6%.
Which is better for coding?
Gemini 3 Pro Preview resolves more real GitHub issues on SWE-bench Verified: Gemini 3 Pro Preview 72.9%, o3 62.3% and Gemini 2.5 Pro 57.6%. All three support tool calling for agent workflows.
Which has the bigger context window?
Gemini 2.5 Pro and Gemini 3 Pro Preview have the largest context windows (1,048,576 and 1,048,576 tokens), against 200,000 for o3. Maximum output per response: Gemini 2.5 Pro up to 65,536, Gemini 3 Pro Preview up to 65,536, o3 up to 100,000 tokens.
Which can read images, PDFs, audio or video?
Gemini 2.5 Pro accepts text, images, PDFs, audio and video; Gemini 3 Pro Preview accepts text, images, PDFs, audio and video; o3 accepts text, images and PDFs. Gemini 2.5 Pro handles the widest range of inputs.
Are any of these open source?
No. Gemini 2.5 Pro, 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. Gemini 2.5 Pro came out Jun 17, 2025; o3 came out Apr 16, 2025. Knowledge cutoff: Gemini 2.5 Pro Jan 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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