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Comparison · 2 models · Updated Oct 4, 2026

Kimi K2.8 Preview vs Grok 4.3

Grok 4.3 comes out ahead, 72 to 66 on our weighted score, and it is the cheaper option too.

  1. Moonshot AI

    Kimi K2.8 Preview

    Released Sep 11, 2026

    66/100
    • ECI—
    • Price—
    • Context1.05M
    Full specs Remove Kimi K2.8 Preview
  2. Our pick

    xAI

    Grok 4.3

    Released Apr 17, 2026

    72/100
    • ECI149.2
    • Price$1.25 / $2.50
    • Context1M
    Full specs Remove Grok 4.3

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Grok 4.3 is our pick

Grok 4.3 is the better all-round choice, scoring 72/100 against Kimi K2.8 Preview (66). It leads on inputs & features. The score weighs inputs & features 60%, context window 40%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

  • CapabilityNot enough dataNo independent benchmark covers every model here yet
  • Lowest priceGrok 4.3Grok 4.3 $1.56 per 1M tokens (3:1 blend) · Kimi K2.8 Preview unpriced
  • Longest contextKimi K2.8 PreviewKimi K2.8 Preview 1,048,576 · Grok 4.3 1,000,000 tokens
  • Widest inputsSame inputsKimi K2.8 Preview: Text, Images, Video · Grok 4.3: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightKimi K2.8 PreviewGrok 4.3
Inputs & features60%7080
Context window40%6160
Overall100%66/10072/100

Left out because at least one model lacks the data: capability and price. The remaining weights were rescaled.

02 — Side by side

Every spec in one table

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

Kimi K2.8 Preview vs Grok 4.3 specifications side by side
SpecificationKimi K2.8 PreviewMoonshot AIGrok 4.3xAI
Capability
Capabilities Index (ECI)—149.2
ECI rank—#55 of 148
GPQA DiamondGraduate-level science questions—88.8%
FrontierMath Tiers 1–3Research-level mathematics—42.8%
OTIS Mock AIME 2024–2025Competition mathematics—93.3%
SimpleQA VerifiedShort factual questions—33.2%
Price per million tokens
Input—$1.25
Output—$2.50
Cached input—$0.20
Blended (3:1)—$1.56
Long-context rate—Over 200K: $2.50 / $5.00
Price source—Official xAI API
Limits
Context window1,048,576 tokens (best)1,000,000 tokens
Max output—30,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsNoYes
AudioNoNo
VideoYesNo
ReasoningYesYeslow · medium · high
Tool callingYesYes
Structured outputNoYes
Availability
WeightsProprietaryProprietary
API model ID—grok-4.3
API providers—27
ReleasedSep 11, 2026Apr 17, 2026
Knowledge cutoff——
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.

  • Kimi K2.8 Preview—
  • Grok 4.3$17.50
04 — Questions

Which should you choose?

Which is better: Kimi K2.8 Preview or Grok 4.3?

Grok 4.3 is the better all-round choice, scoring 72/100 against Kimi K2.8 Preview (66). It leads on inputs & features. The score weighs inputs & features 60%, context window 40%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.

Which is cheaper, Kimi K2.8 Preview or Grok 4.3?

Grok 4.3 is cheaper at $1.25 input / $2.50 output per million tokens (official xAI API price). . At a typical mix of three input tokens to one output token, that is $1.56 per million tokens for Grok 4.3 versus . Kimi K2.8 Preview has no published per-token price.

Which scores higher on benchmarks?

There is no independent benchmark that covers both models yet. Kimi K2.8 Preview has not been scored yet and Grok 4.3 has an ECI of 149.2.

Which is better for coding?

There are no published SWE-bench Verified results for Kimi K2.8 Preview and Grok 4.3 yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.

Which has the bigger context window?

Kimi K2.8 Preview has the largest context window at 1,048,576 tokens, against 1,000,000 for Grok 4.3. Maximum output per response: Grok 4.3 up to 30,000 tokens.

Which can read images, PDFs, audio or video?

Kimi K2.8 Preview accepts text, images and video; Grok 4.3 accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. Kimi K2.8 Preview and Grok 4.3 are proprietary and only available through APIs and apps.

Which is newer?

Kimi K2.8 Preview is the newest, released Sep 11, 2026. Grok 4.3 came out Apr 17, 2026.

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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