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Comparison · 2 models · Updated Oct 4, 2026

Claude Sonnet 4.6 vs Gemini 3.5 Flash

Gemini 3.5 Flash comes out ahead, 69 to 62 on our weighted score, and it is the cheaper option too.

  1. Anthropic

    Claude Sonnet 4.6

    Released Feb 17, 2026

    62/100
    • ECI152.3
    • Price$3.00 / $15.00
    • Context1M
    Full specs Remove Claude Sonnet 4.6
  2. Our pick

    Google

    Gemini 3.5 Flash

    Released May 19, 2026

    69/100
    • ECI154.5
    • Price$1.50 / $9.00
    • Context1.05M
    Full specs Remove Gemini 3.5 Flash

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

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). It leads on capability, 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 · Claude Sonnet 4.6 152.3
  • Lowest priceGemini 3.5 FlashGemini 3.5 Flash $3.38 · 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 tokens
  • Widest inputsGemini 3.5 FlashClaude Sonnet 4.6: Text, Images, PDFs · Gemini 3.5 Flash: Text, Images, PDFs, Audio, Video
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightClaude Sonnet 4.6Gemini 3.5 Flash
CapabilityCapabilities Index (ECI)50%8184
Price25%1325
Inputs & features15%80100
Context window10%6061
Overall100%62/10069/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

Claude Sonnet 4.6 vs Gemini 3.5 Flash specifications side by side
SpecificationClaude Sonnet 4.6AnthropicGemini 3.5 FlashGoogle
Capability
Capabilities Index (ECI)152.3154.5 (best)
ECI rank#40 of 148#33 of 148 (best)
GPQA DiamondGraduate-level science questions87.4%92.8% (best)
FrontierMath Tiers 1–3Research-level mathematics—62.8%
OTIS Mock AIME 2024–2025Competition mathematics85.8%95.6% (best)
SWE-bench VerifiedFixing real GitHub issues75.2%79.3% (best)
SimpleQA VerifiedShort factual questions35.5%66.2% (best)
Price per million tokens
Input$3.00$1.50 (best)
Output$15.00$9.00 (best)
Cached input$0.30$0.15 (best)
Blended (3:1)$6.00$3.38 (best)
Long-context rateSame rateSame rate
Price sourceOfficial Anthropic APIOfficial Google API
Limits
Context window1,000,000 tokens1,048,576 tokens (best)
Max output64,000 tokens65,536 tokens (best)
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoYes
VideoNoYes
ReasoningYeslow · medium · high · maxYesminimal · low · medium · high
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDclaude-sonnet-4-6gemini-3.5-flash
API providers41 (best)32
ReleasedFeb 17, 2026May 19, 2026
Knowledge cutoffAug 31, 2025Jan 2025
03 — Cost

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
04 — Questions

Which should you choose?

Which is better: Claude Sonnet 4.6 or Gemini 3.5 Flash?

Gemini 3.5 Flash is the better all-round choice, scoring 69/100 against Claude Sonnet 4.6 (62). It leads on capability, price and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Claude Sonnet 4.6 or Gemini 3.5 Flash?

Gemini 3.5 Flash is cheaper at $1.50 input / $9.00 output per million tokens (official Google 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 $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) and Claude Sonnet 4.6 152.3 (#40 of 148). The confidence ranges of the top two overlap (152.5–156.6 vs 149.6–154.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 3.5 Flash 92.8%, Claude Sonnet 4.6 87.4%; OTIS Mock AIME 2024–2025 — 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%; SimpleQA Verified — Gemini 3.5 Flash 66.2%, 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% and Claude Sonnet 4.6 75.2%. Both 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. Maximum output per response: Claude Sonnet 4.6 up to 64,000, Gemini 3.5 Flash up to 65,536 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. Gemini 3.5 Flash handles the widest range of inputs.

Are any of these open source?

No. Claude Sonnet 4.6 and Gemini 3.5 Flash 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. Knowledge cutoff: Claude Sonnet 4.6 Aug 31, 2025, Gemini 3.5 Flash 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.

05 — Keep comparing

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