Which is cheaper, Kimi K3 and Grok 4.5?

Grok 4.5 has the lowest input price. Per 1M input tokens: Kimi K3 from $2.70 and Grok 4.5 from $2.00.

Which has the larger context window, Kimi K3 and Grok 4.5?

Kimi K3 has the largest context window: Kimi K3 1,048,576 tokens and Grok 4.5 500,000 tokens.

Which is better for coding, Kimi K3 and Grok 4.5?

Kimi K3 scores highest on the Artificial Analysis Coding Index: Kimi K3 76.2 and Grok 4.5 72.4.

Which is smarter, Kimi K3 and Grok 4.5?

Kimi K3 scores highest on the Artificial Analysis Intelligence Index: Kimi K3 43.6 and Grok 4.5 38.8.

Which is faster, Kimi K3 and Grok 4.5?

Grok 4.5 has the highest median throughput on FastRouter: Kimi K3 <1 t/s and Grok 4.5 <1 t/s.

Can I switch between Kimi K3 and Grok 4.5 without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (moonshotai/kimi-k3, x-ai/grok-4.5).

Kimi K3 vs Grok 4.5

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Kimi K3 MoonshotAImoonshotai/kimi-k3

Grok 4.5 xAIx-ai/grok-4.5

Creator

MoonshotAI

xAI

Released

Jul 16, 2026

Jul 8, 2026

Context window

1.05M

500K

Max output

1.05M

500K

Input / 1MLowest provider price

$2.70$2.70–$3.00 across 4

$2.00

Output / 1MLowest provider price

$13.50$13.50–$15.00 across 4

$6.00

Providers

IntelligenceArtificial Analysis index

43.6

38.8

CodingArtificial Analysis index

76.2

72.4

LatencyMedian time to first token

7.4s

81s

ThroughputMedian tokens per second

<1 t/s

Accepts

Text, Image

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Kimi K3 vs Grok 4.5: summary

Kimi K3 and Grok 4.5 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Kimi K3, from MoonshotAI, has a 1,048,576-token context window, costs from $2.70/1M input and $13.50/1M output tokens across 4 providers and scores 43.6 on the Artificial Analysis Intelligence Index.

Grok 4.5, from xAI, has a 500,000-token context window, costs $2.00/1M input and $6.00/1M output tokens and scores 38.8 on the Artificial Analysis Intelligence Index.

Grok 4.5 is the cheapest on input, 1.4× cheaper than the next model, Kimi K3 has the largest context window, Kimi K3 scores highest for intelligence, Kimi K3 leads on coding and Grok 4.5 has the highest throughput.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="moonshotai/kimi-k3", messages=[...]) # or client.chat.completions.create(model="x-ai/grok-4.5", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis