Model A

xAI

50.6/100

Supported · Public rank #126

90% interval 28.4–72.8

Grok 4.1 Fast vs Kimi K3

Updated August 19, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

Model B

Kimi K3

Moonshot AI

80.5/100

Supported · Public rank #5

90% interval 77.7–83.4

Decision reading

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. Use the documented cost, context, and runtime rows instead.

0 results are shared. Category rows based on different benchmark sets are marked directional and do not name a winner.

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

Long documents
Prompts that approach the documented context limit
Grok 4.1 Fast
Grok 4.1 Fast has the larger documented context window.
Confidence: documented
Chat turn cost
1K fresh input + 500 output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Cache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback

Show secondary and unsupported calls

Repository review cost
50K fresh input + 3K output tokens
Grok 4.1 Fast
Grok 4.1 Fast has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Coding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
No shared weighted benchmark basis supports a winner.
Confidence: limited
Agentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
No shared weighted benchmark basis supports a winner.
Confidence: limited

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

1 Grok 4.1 Fast only

40 Kimi K3 only

Shared results: 0
Grok 4.1 Fast only: 1
Kimi K3 only: 40
Like-for-like categories: 0 / 8

Category results, on a stated basis

Each row states whether both averages use the same weighted benchmark set. Directional and not-comparable rows remain visible, but they never receive a winner in this template.

Agentic

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: 89.5
Weighted basis: 0 vs 2 rows
Reading: Not comparable

Coding

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: Not measured
Weighted basis: 0 vs 0 rows
Reading: Not comparable

Reasoning

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: Not measured
Weighted basis: 0 vs 0 rows
Reading: Not comparable

Knowledge

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: 61.0
Weighted basis: 0 vs 2 rows
Reading: Not comparable

Math

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: Not measured
Weighted basis: 0 vs 0 rows
Reading: Not comparable

Multilingual

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: Not measured
Weighted basis: 0 vs 0 rows
Reading: Not comparable

Multimodal

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: 78.5
Weighted basis: 0 vs 3 rows
Reading: Not comparable

Instruction following

Not comparable

Grok 4.1 Fast: Not measured
Kimi K3: Not measured
Weighted basis: 0 vs 0 rows
Reading: Not comparable

Category averages with the server-provided evidence basis for Grok 4.1 Fast and Kimi K3
Category	Grok 4.1 Fast	Kimi K3	Weighted basis	Reading
Agentic	Not measured	89.5	Not comparable0 vs 2 rows	Not comparable
Coding	Not measured	Not measured	Not comparable0 vs 0 rows	Not comparable
Reasoning	Not measured	Not measured	Not comparable0 vs 0 rows	Not comparable
Knowledge	Not measured	61.0	Not comparable0 vs 2 rows	Not comparable
Math	Not measured	Not measured	Not comparable0 vs 0 rows	Not comparable
Multilingual	Not measured	Not measured	Not comparable0 vs 0 rows	Not comparable
Multimodal	Not measured	78.5	Not comparable0 vs 3 rows	Not comparable
Instruction following	Not measured	Not measured	Not comparable0 vs 0 rows	Not comparable

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

A shared-evidence shape is not available.

BenchLM does not draw a radar or infer missing axes when the matched evidence is too sparse.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

Grok 4.1 Fast: $0.00045; Fits in one request
Kimi K3: $0.0105; Fits in one request

Grok 4.1 Fast has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

Grok 4.1 Fast: $0.0115; Fits in one request
Kimi K3: $0.195; Fits in one request

Grok 4.1 Fast has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

Grok 4.1 Fast: $0.049; Fits in one request; Cached input priced at the published list-input rate
Kimi K3: $0.27; Fits in one request

Grok 4.1 Fast has the lower modeled cost

Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

SpecificationGrok 4.1 FastKimi K3

Context window

Maximum documented context; output-token limits may be lower.

Grok 4.1 Fast

Kimi K3

1.05M

API model ID

Grok 4.1 Fast

Not sourced

Kimi K3

Not sourced

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

Grok 4.1 Fast

Not published

Kimi K3

$0.3 per 1M cached input tokens

Documented inputs

Grok 4.1 Fast

Not sourced

Kimi K3

Not sourced

Documented outputs

Grok 4.1 Fast

Not sourced

Kimi K3

Not sourced

Provider availability

Grok 4.1 Fast

Not sourced

Kimi K3

Not sourced

Reasoning profile

Grok 4.1 Fast

Non-Reasoning

Kimi K3

Reasoning

Weight access

Grok 4.1 Fast

Proprietary

Kimi K3

Pending

License

Grok 4.1 Fast

Proprietary

Kimi K3

Pending

Release date

Grok 4.1 Fast

2025-11-19

Kimi K3

2026-07-16

If you already use one of these models

Deployment change: The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal: The public evidence has no benchmark result shared by both models, so it does not support a quality verdict.
Workload cost: Repository review: $0.0115 vs $0.195. Cache-heavy agent loop: $0.049 vs $0.27.
Context tradeoff: Grok 4.1 Fast has the larger documented window (2M).

Run the same representative tasks against both endpoints before changing production traffic.

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence41 rows

Agentic

Gert Labs
Grok 4.1 Fast47.32%
Source
Kimi K3—
Not directly comparable
Terminal-Bench 2.0
Grok 4.1 Fast—
Kimi K388.3%
Source
Not directly comparable
BrowseComp
Grok 4.1 Fast—
Kimi K391.2%
Source
Not directly comparable
DeepSearchQA
Grok 4.1 Fast—
Kimi K395.0%
Source
Not directly comparable
Toolathlon-Verified
Grok 4.1 Fast—
Kimi K373.2%
Source
Not directly comparable
MCP Atlas
Grok 4.1 Fast—
Kimi K384.2%
Source
Not directly comparable
AutomationBench
Grok 4.1 Fast—
Kimi K330.8%
Source
Not directly comparable
JobBench
Grok 4.1 Fast—
Kimi K352.9%
Source
Not directly comparable
APEX-Agents
Grok 4.1 Fast—
Kimi K337.6%
Source
Not directly comparable
SpreadsheetBench 2
Grok 4.1 Fast—
Kimi K334.8%
Source
Not directly comparable
DECK-Bench
Grok 4.1 Fast—
Kimi K373.5%
Source
Not directly comparable

Coding

deepSwe
Grok 4.1 Fast—
Kimi K367.5%
Source
Not directly comparable
cursorBench32
Grok 4.1 Fast—
Kimi K360.8%
Source
Not directly comparable
FrontierSWE
Grok 4.1 Fast—
Kimi K381.2%
Source
Not directly comparable
ProgramBench
Grok 4.1 Fast—
Kimi K377.8%
Source
Not directly comparable
Kimi Code Bench v2
Grok 4.1 Fast—
Kimi K372.9%
Source
Not directly comparable
sweMarathon
Grok 4.1 Fast—
Kimi K342%
Source
Not directly comparable
PostTrain Bench
Grok 4.1 Fast—
Kimi K336.6%
Source
Not directly comparable
MLS-Bench Lite
Grok 4.1 Fast—
Kimi K348.3%
Source
Not directly comparable
VulcanBench v3
Grok 4.1 Fast—
Kimi K373.9%
Source
Not directly comparable
APEX-SWE
Grok 4.1 Fast—
Kimi K348.0%
Source
Not directly comparable
EEBench
Grok 4.1 Fast—
Kimi K338.3%
Source
Not directly comparable
InferenceEval
Grok 4.1 Fast—
Kimi K339.8%
Source
Not directly comparable
KernelBench Internal
Grok 4.1 Fast—
Kimi K368.5%
Source
Not directly comparable

Knowledge

GPQA
Grok 4.1 Fast—
Kimi K393.5%
Source
Not directly comparable
GPQA-D
Grok 4.1 Fast—
Kimi K393.5%
Source
Not directly comparable
HLE
Grok 4.1 Fast—
Kimi K356%
Source
Not directly comparable
HLE w/o tools
Grok 4.1 Fast—
Kimi K343.5%
Source
Not directly comparable

Multimodal

OfficeQA Pro
Grok 4.1 Fast—
Kimi K363.3%
Source
Not directly comparable
MMMU-Pro
Grok 4.1 Fast—
Kimi K381.6%
Source
Not directly comparable
MMMU-Pro w/ Python
Grok 4.1 Fast—
Kimi K383.4%
Source
Not directly comparable
CharXiv w/o tools
Grok 4.1 Fast—
Kimi K384.8%
Source
Not directly comparable
CharXiv
Grok 4.1 Fast—
Kimi K391.3%
Source
Not directly comparable
MathVision
Grok 4.1 Fast—
Kimi K394.3%
Source
Not directly comparable
MathVision w/ Python
Grok 4.1 Fast—
Kimi K397.8%
Source
Not directly comparable
BabyVision w/ Python
Grok 4.1 Fast—
Kimi K385.7%
Source
Not directly comparable
ZeroBench
Grok 4.1 Fast—
Kimi K323.0%
Source
Not directly comparable
ZeroBench w/ Python
Grok 4.1 Fast—
Kimi K341.0%
Source
Not directly comparable
WorldVQA ForceAnswer
Grok 4.1 Fast—
Kimi K351.0%
Source
Not directly comparable
OmniDocBench
Grok 4.1 Fast—
Kimi K391.1%
Source
Not directly comparable
PerceptionBench
Grok 4.1 Fast—
Kimi K358.5%
Source
Not directly comparable

Frequently asked questions

Which is better, Grok 4.1 Fast or Kimi K3?

The public evidence has no benchmark result shared by both models, so it does not support a quality verdict. The page therefore keeps the decision tied to the specific documented workload.

Which is better for coding, Grok 4.1 Fast or Kimi K3?

The published evidence does not provide a shared weighted coding basis for both models, so BenchLM does not name a coding winner.

Which is better for agentic tasks, Grok 4.1 Fast or Kimi K3?

The published evidence does not provide a shared weighted agentic tasks basis for both models, so BenchLM does not name a agentic tasks winner.

Which costs less, Grok 4.1 Fast or Kimi K3?

For the stated presets, chat costs $0.00045 on Grok 4.1 Fast and $0.0105 on Kimi K3; repository review costs $0.0115 and $0.195; the cache-heavy agent loop costs $0.049 and $0.27. Grok 4.1 Fast has no published cached-input rate, so cached tokens use its listed input rate.

Which has the larger context window, Grok 4.1 Fast or Kimi K3?

Grok 4.1 Fast has the larger documented context window: 2M, compared with 1.05M.

Related comparisons

Compare API pricing Read the methodology Open the model selector

Last updated August 19, 2026

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Grok 4.1 Fast vs Kimi K3

Which one for your work

Long documents

Chat turn cost

Cache-heavy agent loop cost

Repository review cost

Coding work

Agentic work

What is actually comparable

Category results, on a stated basis

Agentic

Coding

Reasoning

Knowledge

Math

Multilingual

Multimodal

Instruction following

Shape of the matched evidence

What each workload costs

Chat turn

Repository review

Cache-heavy agent loop

Specification differences

Context window

API model ID

Cached-input rate

Documented inputs

Documented outputs

Provider availability

Reasoning profile

Weight access

License

Release date

Benchmark evidence

Agentic

Coding

Knowledge

Multimodal

Frequently asked questions

Which is better, Grok 4.1 Fast or Kimi K3?

Which is better for coding, Grok 4.1 Fast or Kimi K3?

Which is better for agentic tasks, Grok 4.1 Fast or Kimi K3?

Which costs less, Grok 4.1 Fast or Kimi K3?

Which has the larger context window, Grok 4.1 Fast or Kimi K3?

Related comparisons

Watch Grok 4.1 Fast vs Kimi K3