API cost decision in 10 seconds

🔥Kimi K3 vs Grok 4.5

Pick Grok 4.5 for lower cost; pick Kimi K3 only if the larger context window matters more.

Page updated:  Data confirmed:  Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Grok 4.5 for lower cost; pick Kimi K3 only if the larger context window matters more.

On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $10.5 for Kimi K3, saving $5.5 (52.4% lower).

Cost-first pickGrok 4.5
Context-first pickKimi K3
Sample savings$5.552.4%
10x traffic gap$55

Kimi K3 has more context, but Grok 4.5 saves $5.5 on the standard workload. At 10x that traffic, the same price gap is about $55. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Grok 4.5 stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shapeToken mixBetter pickKimi K3Grok 4.5
Input-heavy / RAG5M input + 500K outputGrok 4.5$22.5$13
Balanced workload1M input + 1M outputGrok 4.5$18$8
Output-heavy chatbot1M input + 5M outputGrok 4.5$78$32
Cheaper input Grok 4.5 $3 vs $2 / 1M

Grok 4.5 is $1 cheaper per 1M input tokens (33.3% lower; 1.5x difference).

Cheaper output Grok 4.5 $15 vs $6 / 1M

Grok 4.5 is $9 cheaper per 1M output tokens (60% lower; 2.5x difference).

Larger context Kimi K3 1.05M vs 500K

Kimi K3 has 548.58K more context (2.1x larger).

Sample workload Grok 4.5 $10.5 vs $5

Grok 4.5 is $5.5 cheaper on the standard workload (52.4% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.
Kimi K3 Calculating… Estimated API cost
Grok 4.5 Calculating… Estimated API cost
Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

Grok 4.5 has the lower input price; Grok 4.5 has the lower output price; Kimi K3 offers the larger context window. For the 1M input plus 500K output sample, Grok 4.5 is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $10.5 for Kimi K3 and $5 for Grok 4.5.

Best Fit

Choose Kimi K3 when you care most about larger context window.

Choose Grok 4.5 when you care most about lower input-token price, and lower output-token price.

Decision Notes
  • On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $10.5 for Kimi K3, saving $5.5 (52.4% lower).
  • Grok 4.5 is $5.5 cheaper on the standard workload (52.4% lower).
  • Grok 4.5 is $1 cheaper per 1M input tokens (33.3% lower; 1.5x difference).
  • Grok 4.5 is $9 cheaper per 1M output tokens (60% lower; 2.5x difference).
  • Kimi K3 has 548.58K more context (2.1x larger).
Head-to-Head Specs
Feature🔥Kimi K3
(MoonshotAI)		Grok 4.5
(SpaceXAI)
Input Price
prompt tokens per 1M		$3$2
Completion Price
per 1M tokens		$15$6
Sample Workload Cost
1M input + 500K output		$10.5$5
Context Window1.05M500K
Release Date
Popularity#14

Use-Case Decision Matrix

Use caseBetter pickWhy
Budget-constrained productionGrok 4.5On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $10.5 for Kimi K3, saving $5.5 (52.4% lower).
High-volume input processingGrok 4.5Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbotsGrok 4.5Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document workKimi K3A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps
  • Kimi K2.7 Code (free) can replace Kimi K3 when lower sample workload cost matters most: $0.
  • Kimi K2.6 (free) can replace Kimi K3 when lower sample workload cost matters most: $0.
  • Kimi K2.5 can replace Kimi K3 when lower sample workload cost matters most: $1.57.
  • Kimi K2 0711 can replace Kimi K3 when lower sample workload cost matters most: $1.72.

Cheaper alternatives

Review low-cost models sorted by a standard 1M input plus 500K output workload.

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Larger context alternatives

Find models with larger context windows for RAG, long documents, and codebase review.

Open largest context models

Provider catalogs

Compare models within provider hubs before choosing a final API vendor.

Open provider hubs

MoonshotAI catalog

Review all tracked MoonshotAI models before deciding whether this matchup is the right shortlist.

Open MoonshotAI models

SpaceXAI catalog

Check other SpaceXAI models with comparable pricing, context, or release timing.

Open SpaceXAI models
Kimi K3

Kimi K3 is a 2.8T parameter open-weight multimodal reasoning model from Moonshot AI. It is suited for complex coding, knowledge work, and long-horizon agentic workflows, and is particularly strong at...

Grok 4.5

Grok 4.5 is a model from SpaceXAI with frontier performance on coding, knowledge work, and STEM.