o3 vs Gemini 2.0 Flash vs Gemini 2.5 Pro
Gemini 2.5 Pro comes out ahead, 76 to 70 and 65 on our weighted score, and it is the cheaper option too.
OpenAIo3
70/100- ECI146.9
- Price$2.00 / $8.00
- Context200K
GoogleGemini 2.0 Flash
65/100- ECI134.7
- Price—
- Context1.05M
- Our pickGoogle
Gemini 2.5 Pro
76/100- ECI145.3
- Price$1.25 / $10.00
- Context1.05M
Gemini 2.5 Pro is our pick
Gemini 2.5 Pro is the better all-round choice, scoring 76/100 against o3 (70) and Gemini 2.0 Flash (65). It leads on inputs & features. o3 wins on capability. The score weighs capability 67%, inputs & features 20%, context window 13%.
- Capabilityo3Capabilities Index (ECI): o3 146.9 · Gemini 2.5 Pro 145.3 · Gemini 2.0 Flash 134.7
- Lowest priceGemini 2.5 ProGemini 2.5 Pro $3.44 · o3 $3.50 per 1M tokens (3:1 blend) · Gemini 2.0 Flash unpriced
- Longest contextGemini 2.0 Flash and Gemini 2.5 ProGemini 2.0 Flash 1,048,576 · Gemini 2.5 Pro 1,048,576 · o3 200,000 tokens
- Widest inputsGemini 2.0 Flash and Gemini 2.5 Proo3: Text, Images, PDFs · Gemini 2.0 Flash: Text, Images, PDFs, Audio, Video · Gemini 2.5 Pro: Text, Images, PDFs, Audio, Video
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | o3 | Gemini 2.0 Flash | Gemini 2.5 Pro |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 67% | 74 | 59 | 72 |
| Inputs & features | 20% | 80 | 90 | 100 |
| Context window | 13% | 32 | 61 | 61 |
| Overall | 100% | 70/100 | 65/100 | 76/100 |
Left out because at least one model lacks the data: price. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | o3OpenAI | Gemini 2.0 FlashGoogle | Gemini 2.5 ProGoogle |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 146.9 (best) | 134.7 | 145.3 |
| ECI rank | #63 of 148 (best) | #116 of 148 | #78 of 148 |
| GPQA DiamondGraduate-level science questions | 81.8% | — | 85.3% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 33.3% (best) | — | 24.6% |
| OTIS Mock AIME 2024–2025Competition mathematics | 84.4% | — | 84.7% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 62.3% (best) | — | 57.6% |
| SimpleQA VerifiedShort factual questions | 49.4% | — | — |
| Price per million tokens | |||
| Input | $2.00 | — | $1.25 (best) |
| Output | $8.00 (best) | — | $10.00 |
| Cached input | $0.50 | — | $0.125 (best) |
| Blended (3:1) | $3.50 | — | $3.44 (best) |
| Long-context rate | Same rate | — | Over 200K: $2.50 / $15.00 |
| Price source | Official OpenAI API | — | Official Google API |
| Limits | |||
| Context window | 200,000 tokens | 1,048,576 tokens (best) | 1,048,576 tokens (best) |
| Max output | 100,000 tokens (best) | 8,192 tokens | 65,536 tokens |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | Yes |
| Audio | No | Yes | Yes |
| Video | No | Yes | Yes |
| Reasoning | Yeslow · medium · high | No | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | o3 | — | gemini-2.5-pro |
| API providers | 18 | — | 22 (best) |
| Released | Apr 16, 2025 | Dec 11, 2024 | Jun 17, 2025 |
| Knowledge cutoff | May 2024 | Jun 2024 | Jan 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
- Gemini 2.0 Flash—
- Gemini 2.5 Pro$32.50
Which should you choose?
Which is better: o3, Gemini 2.0 Flash or Gemini 2.5 Pro?
Gemini 2.5 Pro is the better all-round choice, scoring 76/100 against o3 (70) and Gemini 2.0 Flash (65). It leads on inputs & features. o3 wins on capability. The score weighs capability 67%, inputs & features 20%, context window 13%.
Which is cheaper, o3, Gemini 2.0 Flash or Gemini 2.5 Pro?
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). 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). Gemini 2.0 Flash has no published per-token price.
Which scores higher on benchmarks?
o3 scores higher on the Capabilities Index (ECI): o3 146.9 (#63 of 148), Gemini 2.5 Pro 145.3 (#78 of 148) and Gemini 2.0 Flash 134.7 (#116 of 148). The confidence ranges of the top two overlap (144.9–148.6 vs 143.6–146.9), so treat the gap as small.
Which is better for coding?
There are no published SWE-bench Verified results for Gemini 2.0 Flash yet, so there is no like-for-like coding score. On overall capability, o3 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?
Gemini 2.0 Flash and Gemini 2.5 Pro have the largest context windows (1,048,576 and 1,048,576 tokens), against 200,000 for o3. Maximum output per response: o3 up to 100,000, Gemini 2.0 Flash up to 8,192, Gemini 2.5 Pro up to 65,536 tokens.
Which can read images, PDFs, audio or video?
o3 accepts text, images and PDFs; Gemini 2.0 Flash accepts text, images, PDFs, audio and video; Gemini 2.5 Pro accepts text, images, PDFs, audio and video. Gemini 2.0 Flash handles the widest range of inputs.
Are any of these open source?
No. o3, Gemini 2.0 Flash and Gemini 2.5 Pro are proprietary and only available through APIs and apps.
Which is newer?
Gemini 2.5 Pro is the newest, released Jun 17, 2025. o3 came out Apr 16, 2025; Gemini 2.0 Flash came out Dec 11, 2024. Knowledge cutoff: o3 May 2024, Gemini 2.0 Flash Jun 2024, Gemini 2.5 Pro Jan 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.
