ZMIME
Comparison · 3 models · Updated Oct 4, 2026

Gemini 3.6 Flash vs Grok 4.20 (Reasoning) vs Kimi K2.6

Gemini 3.6 Flash comes out ahead, 73 to 68 and 65 on our weighted score, and it is the cheaper option too.

  1. Our pick

    Google

    Gemini 3.6 Flash

    Released Jul 21, 2026

    73/100
    • ECI154.3
    • Price$0.75 / $3.75
    • Context1.05M
    Full specs Remove Gemini 3.6 Flash

  2. xAI

    Grok 4.20 (Reasoning)

    Released Mar 9, 2026

    68/100
    • ECI152.0
    • Price$1.25 / $2.50
    • Context1M
    Full specs Remove Grok 4.20 (Reasoning)

  3. Moonshot AI

    Kimi K2.6

    Released Apr 21, 2026

    65/100
    • ECI151.1
    • Price$0.95 / $4.00
    • Context262K
    Full specs Remove Kimi K2.6
01 — Verdict

Gemini 3.6 Flash is our pick

Gemini 3.6 Flash is the better all-round choice, scoring 73/100 against Grok 4.20 (Reasoning) (68) and Kimi K2.6 (65). It leads on capability and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGemini 3.6 FlashCapabilities Index (ECI): Gemini 3.6 Flash 154.3 · Grok 4.20 (Reasoning) 152.0 · Kimi K2.6 151.1
  • Lowest priceGemini 3.6 FlashGemini 3.6 Flash $1.50 · Grok 4.20 (Reasoning) $1.56 · Kimi K2.6 $1.71 per 1M tokens (3:1 blend)
  • Longest contextGemini 3.6 FlashGemini 3.6 Flash 1,048,576 · Grok 4.20 (Reasoning) 1,000,000 · Kimi K2.6 262,144 tokens
  • Widest inputsGemini 3.6 FlashGemini 3.6 Flash: Text, Images, PDFs, Audio, Video · Grok 4.20 (Reasoning): Text, Images, PDFs · Kimi K2.6: Text, Images, Video
  • Self-hostingKimi K2.6Publishes downloadable weights
How the score is built
MeasureWeightGemini 3.6 FlashGrok 4.20 (Reasoning)Kimi K2.6
CapabilityCapabilities Index (ECI)50%848179
Price25%424139
Inputs & features15%1008080
Context window10%616037
Overall100%73/10068/10065/100
02 — Side by side

Every spec in one table

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

Gemini 3.6 Flash vs Grok 4.20 (Reasoning) vs Kimi K2.6 specifications side by side
SpecificationGemini 3.6 FlashGoogleGrok 4.20 (Reasoning)xAIKimi K2.6Moonshot AI
Capability
Capabilities Index (ECI)154.3 (best)152.0151.1
ECI rank#34 of 148 (best)#41 of 148#45 of 148
GPQA DiamondGraduate-level science questions94.1% (best)89.3%90.8%
FrontierMath Tiers 1–3Research-level mathematics59.0% (best)44.9%57.2%
OTIS Mock AIME 2024–2025Competition mathematics94.2%92.2%96.1% (best)
SWE-bench VerifiedFixing real GitHub issues——76.7%
SimpleQA VerifiedShort factual questions66.2% (best)30.2%34.9%
Price per million tokens
Input$0.75 (best)$1.25$0.95
Output$3.75$2.50 (best)$4.00
Cached input$0.075 (best)$0.20$0.16
Blended (3:1)$1.50 (best)$1.56$1.71
Long-context rateSame rateOver 200K: $2.50 / $5.00Same rate
Price sourceOfficial Google APIOfficial xAI APIOfficial Moonshot AI API
Limits
Context window1,048,576 tokens (best)1,000,000 tokens262,144 tokens
Max output65,536 tokens30,000 tokens262,144 tokens (best)
Inputs and features
TextYesYesYes
ImagesYesYesYes
PDFsYesYesNo
AudioYesNoNo
VideoYesNoYes
ReasoningYesminimal · low · medium · highYesYes
Tool callingYesYesYes
Structured outputYesYesYes
Availability
WeightsProprietaryProprietaryOpen
API model IDgemini-3.6-flashgrok-4.20-0309-reasoningkimi-k2.6
API providers251146 (best)
ReleasedJul 21, 2026Mar 9, 2026Apr 21, 2026
Knowledge cutoffMar 2026—Jan 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.

  • Gemini 3.6 Flash$15.00
  • Grok 4.20 (Reasoning)$17.50
  • Kimi K2.6$17.50
04 — Questions

Which should you choose?

Which is better: Gemini 3.6 Flash, Grok 4.20 (Reasoning) or Kimi K2.6?

Gemini 3.6 Flash is the better all-round choice, scoring 73/100 against Grok 4.20 (Reasoning) (68) and Kimi K2.6 (65). It leads on capability and inputs & features. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Gemini 3.6 Flash, Grok 4.20 (Reasoning) or Kimi K2.6?

Gemini 3.6 Flash is cheaper at $0.75 input / $3.75 output per million tokens (official Google API price). Grok 4.20 (Reasoning) costs $1.25 input / $2.50 output per million tokens (official xAI API price); Kimi K2.6 costs $0.95 input / $4.00 output per million tokens (official Moonshot AI API price). At a typical mix of three input tokens to one output token, that is $1.50 per million tokens for Gemini 3.6 Flash versus $1.56 for Grok 4.20 (Reasoning) (1× as much) and $1.71 for Kimi K2.6 (1.1× as much).

Which scores higher on benchmarks?

Gemini 3.6 Flash scores higher on the Capabilities Index (ECI): Gemini 3.6 Flash 154.3 (#34 of 148), Grok 4.20 (Reasoning) 152.0 (#41 of 148) and Kimi K2.6 151.1 (#45 of 148). The confidence ranges of the top two overlap (152.6–156.3 vs 149.3–154.4), so treat the gap as small. On individual benchmarks: GPQA Diamond — Gemini 3.6 Flash 94.1%, Kimi K2.6 90.8%, Grok 4.20 (Reasoning) 89.3%; FrontierMath Tiers 1–3 — Gemini 3.6 Flash 59.0%, Kimi K2.6 57.2%, Grok 4.20 (Reasoning) 44.9%; OTIS Mock AIME 2024–2025 — Kimi K2.6 96.1%, Gemini 3.6 Flash 94.2%, Grok 4.20 (Reasoning) 92.2%; SimpleQA Verified — Gemini 3.6 Flash 66.2%, Kimi K2.6 34.9%, Grok 4.20 (Reasoning) 30.2%.

Which is better for coding?

There are no published SWE-bench Verified results for Gemini 3.6 Flash and Grok 4.20 (Reasoning) yet, so there is no like-for-like coding score. On overall capability, Gemini 3.6 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 3.6 Flash has the largest context window at 1,048,576 tokens, against 1,000,000 for Grok 4.20 (Reasoning) and 262,144 for Kimi K2.6. Maximum output per response: Gemini 3.6 Flash up to 65,536, Grok 4.20 (Reasoning) up to 30,000, Kimi K2.6 up to 262,144 tokens.

Which can read images, PDFs, audio or video?

Gemini 3.6 Flash accepts text, images, PDFs, audio and video; Grok 4.20 (Reasoning) accepts text, images and PDFs; Kimi K2.6 accepts text, images and video. Gemini 3.6 Flash handles the widest range of inputs.

Are any of these open source?

Kimi K2.6 publishes its weights and can be self-hosted; Gemini 3.6 Flash and Grok 4.20 (Reasoning) is proprietary.

Which is newer?

Gemini 3.6 Flash is the newest, released Jul 21, 2026. Kimi K2.6 came out Apr 21, 2026; Grok 4.20 (Reasoning) came out Mar 9, 2026. Knowledge cutoff: Gemini 3.6 Flash Mar 2026, Kimi K2.6 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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