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Head-to-head comparison

Gemini 3.8 Flash vs Grok 4.6

Gemini 3.8 Flash (Google) and Grok 4.6 (xAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 3 September 2026

As of 3 September 2026, Gemini 3.8 Flash holds the stronger ModelCap Index position (#11 vs #16); Gemini 3.8 Flash is 1.6× cheaper per output token ($3.75/1M vs $6.00/1M); and Gemini 3.8 Flash offers the longer context window (1M vs 500K tokens).

Which should you choose?

Choose Gemini 3.8 Flash if…

  • you want the stronger overall ModelCap Index position — #11 against #16 (76.4 vs 73.2 points).
  • API cost matters — $3.75/1M output tokens against $6.00/1M, about 1.6× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.75/1M against $2.00/1M.
  • you need the longer context window — 1M tokens against 500K.
  • AA Humanity's Last Exam is your yardstick — 47.8% against 42.9%.
  • you want the more recently listed model — Gemini 3.8 Flash was listed 2 September 2026, Grok 4.6 12 August 2026.

Choose Grok 4.6 if…

  • AA Intelligence Index is your yardstick — 60.9 against 58.7.
  • AA Terminal-Bench 2.1 is your yardstick — 88.4% against 87.6%.

Gemini 3.8 Flash vs Grok 4.6: specs, pricing and context

Specification comparison of Gemini 3.8 Flash and Grok 4.6
FieldGemini 3.8 FlashGoogleGrok 4.6xAI
ModelCap Index position#11#16
Index score76.473.2
EvidenceMeasuredMeasured
Input price / 1M tokens$0.75$2.00
Output price / 1M tokens$3.75$6.00
Context window1M tokens500K tokens
Max output tokens66K450K
API providers listed22
Weight accessAPI onlyAPI only
Input modalitiesText, Image, Video, File, AudioText, Image, File
First listed2 September 202612 August 2026
PublisherGooglexAI

Evidence: 1 public benchmark observation across 1 board · 6 public benchmark observations across 6 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Gemini 3.8 Flash vs Grok 4.6

Public benchmark boards where Gemini 3.8 Flash or Grok 4.6 has a published result
BoardGemini 3.8 FlashGrok 4.6Leads
Arena codingArena (LMArena)—15111490–1532HighOnly one result
LMArena AgentLMArena—5.8%4.5%–7.0%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation—67.1%X-HighOnly one result
ARC-AGI-3ARC Prize Foundation—2.1%X-HighOnly one result
AA Intelligence IndexArtificial Analysis58.7intelligence-index60.9intelligence-indexGrok 4.6
AA Terminal-Bench 2.1Artificial Analysis87.6%terminal-bench-2.188.4%terminal-bench-2.1Grok 4.6
AA Humanity's Last ExamArtificial Analysis47.8%humanitys-last-exam42.9%humanitys-last-examGemini 3.8 Flash
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—20.3%17.2%–23.4%Grok Build · HighOnly one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Gemini 3.8 Flash vs Grok 4.6: common questions

Is Gemini 3.8 Flash better than Grok 4.6?

Gemini 3.8 Flash ranks higher on the ModelCap Index as of 3 September 2026: #11 against #16. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it.

Is Gemini 3.8 Flash cheaper than Grok 4.6?

Gemini 3.8 Flash is cheaper on output tokens: $3.75/1M against $6.00/1M. Input tokens are $0.75/1M for Gemini 3.8 Flash and $2.00/1M for Grok 4.6. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, Gemini 3.8 Flash or Grok 4.6?

Gemini 3.8 Flash has the larger context window: 1M tokens against 500K.

Which is better for coding, Gemini 3.8 Flash or Grok 4.6?

AA Terminal-Bench 2.1: Gemini 3.8 Flash 87.6%, Grok 4.6 88.4% — Grok 4.6 leads.

Are Gemini 3.8 Flash and Grok 4.6 open-weight models?

Gemini 3.8 Flash: API only. Grok 4.6: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Gemini 3.8 Flash and Grok 4.6?

ModelCap currently lists 2 API providers for Gemini 3.8 Flash and 2 for Grok 4.6, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Gemini 3.8 Flash vs Grok 4.6 comparison?

Every figure comes from the sealed ModelCap dataset published 3 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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