Claude Sonnet 4.5 vs Kimi K2 Thinking
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
Claude Sonnet 4.5 by Anthropic wins on 5 of 9 benchmarks against Kimi K2 Thinking by Vertex, which leads on 4. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
Coding: In coding, Claude Sonnet 4.5 scores 52.1 on AA Coding Index compared to Kimi K2 Thinking's 21, while Claude Sonnet 4.5 scores 1184 on Design Arena ELO compared to Kimi K2 Thinking's 1125, while Claude Sonnet 4.5 scores 1202 on Website Arena ELO compared to Kimi K2 Thinking's 1125.
Reasoning: In reasoning, Kimi K2 Thinking scores 83.4% on GPQA Diamond compared to Claude Sonnet 4.5's 82.5%, while Claude Sonnet 4.5 scores 73.0% on τ²-Bench Airline compared to Kimi K2 Thinking's 69.2%.
Context: In context, Claude Sonnet 4.5 scores 1.0M on Context Length compared to Kimi K2 Thinking's 262K.
Pricing Comparison
Claude Sonnet 4.5 costs $3.0/1M input tokens and $15.0/1M output tokens, while Kimi K2 Thinking costs $0.60/1M input and $2.5/1M output. Kimi K2 Thinking is the more affordable option for API usage.
Verdict
Kimi K2 Thinking leads across the board in affordability, making it the stronger overall choice in this comparison.
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Claude Sonnet 4.5 vs Kimi K2 Thinking — FAQ
Which is better, Claude Sonnet 4.5 or Kimi K2 Thinking?
Claude Sonnet 4.5 wins on more benchmarks overall (5 vs 4). However, the best choice depends on your specific needs — each model excels in different areas.
How does Claude Sonnet 4.5 compare to Kimi K2 Thinking for coding?
SWE-bench Verified data is not available for both models. Check the detailed comparison charts above for other coding-related metrics.
Is Claude Sonnet 4.5 cheaper than Kimi K2 Thinking?
Yes, Kimi K2 Thinking is cheaper. Claude Sonnet 4.5 costs $3.0/1M input and $15.0/1M output tokens. Kimi K2 Thinking costs $0.60/1M input and $2.5/1M output tokens.
Which is faster, Claude Sonnet 4.5 or Kimi K2 Thinking?
Output speed data is not available for both models. Check the speed section of the comparison above for available performance data.
What benchmarks does the Claude Sonnet 4.5 vs Kimi K2 Thinking comparison cover?
This comparison covers 9 benchmarks including GPQA Diamond, Input Cost, Output Cost, Context Length, AA Coding Index, Cached Input Cost, Design Arena ELO, τ²-Bench Airline, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.