Claude Sonnet 4.6 vs Gemini 3.5 Flash vs GPT-5.2
Gemini 3.5 Flash comes out ahead, 69 to 62 and 61 on our weighted score, and it is the cheaper option too.
AnthropicClaude Sonnet 4.6
62/100- ECI152.3
- Price$3.00 / $15.00
- Context1M
- Our pick
GoogleGemini 3.5 Flash
69/100- ECI154.5
- Price$1.50 / $9.00
- Context1.05M
OpenAIGPT-5.2
61/100- ECI153.5
- Price$1.75 / $14.00
- Context400K
Gemini 3.5 Flash is our pick
Gemini 3.5 Flash is the better all-round choice, scoring 69/100 against Claude Sonnet 4.6 (62) and GPT-5.2 (61). It leads on price and inputs & features. 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 · GPT-5.2 153.5 · Claude Sonnet 4.6 152.3
- Lowest priceGemini 3.5 FlashGemini 3.5 Flash $3.38 · GPT-5.2 $4.81 · Claude Sonnet 4.6 $6.00 per 1M tokens (3:1 blend)
- Longest contextGemini 3.5 FlashGemini 3.5 Flash 1,048,576 · Claude Sonnet 4.6 1,000,000 · GPT-5.2 400,000 tokens
- Widest inputsGemini 3.5 FlashClaude Sonnet 4.6: Text, Images, PDFs · Gemini 3.5 Flash: Text, Images, PDFs, Audio, Video · GPT-5.2: Text, Images
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Sonnet 4.6 | Gemini 3.5 Flash | GPT-5.2 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 81 | 84 | 83 |
| Price | 25% | 13 | 25 | 18 |
| Inputs & features | 15% | 80 | 100 | 70 |
| Context window | 10% | 60 | 61 | 44 |
| Overall | 100% | 62/100 | 69/100 | 61/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 4.6Anthropic | Gemini 3.5 FlashGoogle | GPT-5.2OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 152.3 | 154.5 (best) | 153.5 |
| ECI rank | #40 of 148 | #33 of 148 (best) | #38 of 148 |
| GPQA DiamondGraduate-level science questions | 87.4% | 92.8% (best) | 91.4% |
| FrontierMath Tiers 1–3Research-level mathematics | — | 62.8% | 67.4% (best) |
| OTIS Mock AIME 2024–2025Competition mathematics | 85.8% | 95.6% | 96.1% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 75.2% | 79.3% (best) | 73.8% |
| SimpleQA VerifiedShort factual questions | 35.5% | 66.2% (best) | 37.1% |
| Price per million tokens | |||
| Input | $3.00 | $1.50 (best) | $1.75 |
| Output | $15.00 | $9.00 (best) | $14.00 |
| Cached input | $0.30 | $0.15 (best) | $0.175 |
| Blended (3:1) | $6.00 | $3.38 (best) | $4.81 |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official Google API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens | 1,048,576 tokens (best) | 400,000 tokens |
| Max output | 64,000 tokens | 65,536 tokens | 128,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | No |
| Audio | No | Yes | No |
| Video | No | Yes | No |
| Reasoning | Yeslow · medium · high · max | Yesminimal · low · medium · high | Yeslow · medium · high · xhigh |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-sonnet-4-6 | gemini-3.5-flash | gpt-5.2 |
| API providers | 41 (best) | 32 | 21 |
| Released | Feb 17, 2026 | May 19, 2026 | Dec 11, 2025 |
| Knowledge cutoff | Aug 31, 2025 | Jan 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.
- Claude Sonnet 4.6$60.00
- Gemini 3.5 Flash$33.00
- GPT-5.2$45.50
Which should you choose?
Which is better: Claude Sonnet 4.6, Gemini 3.5 Flash or GPT-5.2?
Gemini 3.5 Flash is the better all-round choice, scoring 69/100 against Claude Sonnet 4.6 (62) and GPT-5.2 (61). It leads on price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 4.6, Gemini 3.5 Flash or GPT-5.2?
Gemini 3.5 Flash is cheaper at $1.50 input / $9.00 output per million tokens (official Google API price). GPT-5.2 costs $1.75 input / $14.00 output per million tokens (official OpenAI 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 $3.38 per million tokens for Gemini 3.5 Flash versus $4.81 for GPT-5.2 (1.4× as much) and $6.00 for Claude Sonnet 4.6 (1.8× 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), GPT-5.2 153.5 (#38 of 148) and Claude Sonnet 4.6 152.3 (#40 of 148). The confidence ranges of the top two overlap (152.5–156.6 vs 151.7–155.4), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 3.5 Flash 92.8%, GPT-5.2 91.4%, Claude Sonnet 4.6 87.4%; OTIS Mock AIME 2024–2025 — GPT-5.2 96.1%, Gemini 3.5 Flash 95.6%, Claude Sonnet 4.6 85.8%; SWE-bench Verified — Gemini 3.5 Flash 79.3%, Claude Sonnet 4.6 75.2%, GPT-5.2 73.8%; SimpleQA Verified — Gemini 3.5 Flash 66.2%, GPT-5.2 37.1%, Claude Sonnet 4.6 35.5%.
Which is better for coding?
Gemini 3.5 Flash resolves more real GitHub issues on SWE-bench Verified: Gemini 3.5 Flash 79.3%, Claude Sonnet 4.6 75.2% and GPT-5.2 73.8%. All three support tool calling for agent workflows.
Which has the bigger context window?
Gemini 3.5 Flash has the largest context window at 1,048,576 tokens, against 1,000,000 for Claude Sonnet 4.6 and 400,000 for GPT-5.2. Maximum output per response: Claude Sonnet 4.6 up to 64,000, Gemini 3.5 Flash up to 65,536, GPT-5.2 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 4.6 accepts text, images and PDFs; Gemini 3.5 Flash accepts text, images, PDFs, audio and video; GPT-5.2 accepts text and images. Gemini 3.5 Flash handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 4.6, Gemini 3.5 Flash and GPT-5.2 are proprietary and only available through APIs and apps.
Which is newer?
Gemini 3.5 Flash is the newest, released May 19, 2026. Claude Sonnet 4.6 came out Feb 17, 2026; GPT-5.2 came out Dec 11, 2025. Knowledge cutoff: Claude Sonnet 4.6 Aug 31, 2025, Gemini 3.5 Flash Jan 2025, GPT-5.2 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.
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