Gemini 3.5 Flash vs Gemini 3 Pro Preview vs Grok 4.5
Too close to call on our weighted score (Gemini 3.5 Flash 69, Gemini 3 Pro Preview 67, Grok 4.5 64). The right pick depends on what you value most.
GoogleGemini 3.5 Flash
69/100- ECI154.5
- Price$1.50 / $9.00
- Context1.05M
- Google
Gemini 3 Pro Preview
67/100- ECI153.0
- Price$2.00 / $12.00
- Context1.05M
xAIGrok 4.5
64/100- ECI154.0
- Price$2.00 / $6.00
- Context500K
Too close to call
It is close. Our weighted score puts them within 2 points (Gemini 3.5 Flash 69/100, Gemini 3 Pro Preview 67/100, Grok 4.5 64/100), so choose by what matters most for your work: Gemini 3.5 Flash for raw capability and Grok 4.5 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGemini 3.5 FlashCapabilities Index (ECI): Gemini 3.5 Flash 154.5 · Grok 4.5 154.0 · Gemini 3 Pro Preview 153.0
- Lowest priceGrok 4.5Grok 4.5 $3.00 · Gemini 3.5 Flash $3.38 · Gemini 3 Pro Preview $4.50 per 1M tokens (3:1 blend)
- Longest contextGemini 3.5 Flash and Gemini 3 Pro PreviewGemini 3.5 Flash 1,048,576 · Gemini 3 Pro Preview 1,048,576 · Grok 4.5 500,000 tokens
- Widest inputsGemini 3.5 Flash and Gemini 3 Pro PreviewGemini 3.5 Flash: Text, Images, PDFs, Audio, Video · Gemini 3 Pro Preview: Text, Images, PDFs, Audio, Video · Grok 4.5: Text, Images
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Gemini 3.5 Flash | Gemini 3 Pro Preview | Grok 4.5 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 84 | 82 | 83 |
| Price | 25% | 25 | 19 | 27 |
| Inputs & features | 15% | 100 | 100 | 70 |
| Context window | 10% | 61 | 61 | 48 |
| Overall | 100% | 69/100 | 67/100 | 64/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Gemini 3.5 FlashGoogle | Gemini 3 Pro PreviewGoogle | Grok 4.5xAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 154.5 (best) | 153.0 | 154.0 |
| ECI rank | #33 of 148 (best) | #39 of 148 | #36 of 148 |
| GPQA DiamondGraduate-level science questions | 92.8% | 92.6% | 93.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 62.8% (best) | — | 57.2% |
| OTIS Mock AIME 2024–2025Competition mathematics | 95.6% | 91.4% | 97.8% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 79.3% (best) | 72.9% | — |
| SimpleQA VerifiedShort factual questions | 66.2% (best) | — | 48.3% |
| Price per million tokens | |||
| Input | $1.50 (best) | $2.00 | $2.00 |
| Output | $9.00 | $12.00 | $6.00 (best) |
| Cached input | $0.15 (best) | — | $0.30 |
| Blended (3:1) | $3.38 | $4.50 | $3.00 (best) |
| Long-context rate | Same rate | Same rate | Over 200K: $4.00 / $12.00 |
| Price source | Official Google API | Median of 2 providers | Official xAI API |
| Limits | |||
| Context window | 1,048,576 tokens (best) | 1,048,576 tokens (best) | 500,000 tokens |
| Max output | 65,536 tokens | 65,536 tokens | 500,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | No |
| Audio | Yes | Yes | No |
| Video | Yes | Yes | No |
| Reasoning | Yesminimal · low · medium · high | Yes | Yeslow · medium · high |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | gemini-3.5-flash | — | grok-4.5 |
| API providers | 32 (best) | 3 | 24 |
| Released | May 19, 2026 | Nov 18, 2025 | Jul 8, 2026 |
| Knowledge cutoff | Jan 2025 | 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.
- Gemini 3.5 Flash$33.00
- Gemini 3 Pro Preview$44.00
- Grok 4.5$32.00
Which should you choose?
Which is better: Gemini 3.5 Flash, Gemini 3 Pro Preview or Grok 4.5?
It is close. Our weighted score puts them within 2 points (Gemini 3.5 Flash 69/100, Gemini 3 Pro Preview 67/100, Grok 4.5 64/100), so choose by what matters most for your work: Gemini 3.5 Flash for raw capability and Grok 4.5 on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Gemini 3.5 Flash, Gemini 3 Pro Preview or Grok 4.5?
Grok 4.5 is cheaper at $2.00 input / $6.00 output per million tokens (official xAI API price). Gemini 3.5 Flash costs $1.50 input / $9.00 output per million tokens (official Google 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 $3.00 per million tokens for Grok 4.5 versus $3.38 for Gemini 3.5 Flash (1.1× as much) and $4.50 for Gemini 3 Pro Preview (1.5× as much).
Which scores higher on benchmarks?
Gemini 3.5 Flash scores higher on the Capabilities Index (ECI): Gemini 3.5 Flash 154.5 (#33 of 148), Grok 4.5 154.0 (#36 of 148) and Gemini 3 Pro Preview 153.0 (#39 of 148). The confidence ranges of the top two overlap (152.5–156.6 vs 152.3–156.1), so treat the gap as small. On individual benchmarks: GPQA Diamond — Grok 4.5 93.4%, Gemini 3.5 Flash 92.8%, Gemini 3 Pro Preview 92.6%; OTIS Mock AIME 2024–2025 — Grok 4.5 97.8%, Gemini 3.5 Flash 95.6%, Gemini 3 Pro Preview 91.4%.
Which is better for coding?
There are no published SWE-bench Verified results for Grok 4.5 yet, so there is no like-for-like coding score. On overall capability, Gemini 3.5 Flash 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 3.5 Flash and Gemini 3 Pro Preview have the largest context windows (1,048,576 and 1,048,576 tokens), against 500,000 for Grok 4.5. Maximum output per response: Gemini 3.5 Flash up to 65,536, Gemini 3 Pro Preview up to 65,536, Grok 4.5 up to 500,000 tokens.
Which can read images, PDFs, audio or video?
Gemini 3.5 Flash accepts text, images, PDFs, audio and video; Gemini 3 Pro Preview accepts text, images, PDFs, audio and video; Grok 4.5 accepts text and images. Gemini 3.5 Flash handles the widest range of inputs.
Are any of these open source?
No. Gemini 3.5 Flash, Gemini 3 Pro Preview and Grok 4.5 are proprietary and only available through APIs and apps.
Which is newer?
Grok 4.5 is the newest, released Jul 8, 2026. Gemini 3.5 Flash came out May 19, 2026; Gemini 3 Pro Preview came out Nov 18, 2025. Knowledge cutoff: Gemini 3.5 Flash Jan 2025, Gemini 3 Pro Preview 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.
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