GPT-5.1 vs Kimi K2.5
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
GPT-5.1 by OpenAI wins on 6 of 11 benchmarks against Kimi K2.5 by Moonshot AI, which leads on 5. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
Coding: In coding, GPT-5.1 scores 49.4 on AA Coding Index compared to Kimi K2.5's 46.8, while Kimi K2.5 scores 1228 on Design Arena ELO compared to GPT-5.1's 1158, while Kimi K2.5 scores 1261 on Website Arena ELO compared to GPT-5.1's 1179.
Reasoning: In reasoning, GPT-5.1 scores 86.2% on GPQA Diamond compared to Kimi K2.5's 84.9%, while GPT-5.1 scores 75.7% on τ²-Bench Airline compared to Kimi K2.5's 71.2%.
Context: In context, GPT-5.1 scores 400K on Context Length compared to Kimi K2.5's 262K.
Pricing Comparison
GPT-5.1 costs $1.3/1M input tokens and $10.0/1M output tokens, while Kimi K2.5 costs $0.45/1M input and $2.3/1M output. Kimi K2.5 is the more affordable option for API usage.
Speed Comparison
GPT-5.1 generates output at 95 tok/s compared to Kimi K2.5's 45 tok/s, and the time to first token is 350 ms for GPT-5.1 versus 1210 ms for Kimi K2.5. GPT-5.1 delivers faster throughput.
Verdict
For developers prioritizing speed, GPT-5.1 has the edge. For those who value affordability, Kimi K2.5 is the stronger choice.
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GPT-5.1 vs Kimi K2.5 — FAQ
Which is better, GPT-5.1 or Kimi K2.5?
GPT-5.1 wins on more benchmarks overall (6 vs 5). However, the best choice depends on your specific needs — each model excels in different areas.
How does GPT-5.1 compare to Kimi K2.5 for coding?
SWE-bench Verified data is not available for both models. Check the detailed comparison charts above for other coding-related metrics.
Is GPT-5.1 cheaper than Kimi K2.5?
Yes, Kimi K2.5 is cheaper. GPT-5.1 costs $1.3/1M input and $10.0/1M output tokens. Kimi K2.5 costs $0.45/1M input and $2.3/1M output tokens.
Which is faster, GPT-5.1 or Kimi K2.5?
GPT-5.1 is faster, generating output at 95 tok/s compared to 45 tok/s. Faster output speed means shorter wait times for API responses.
What benchmarks does the GPT-5.1 vs Kimi K2.5 comparison cover?
This comparison covers 11 benchmarks including GPQA Diamond, Output Speed, Time to First Token, Input Cost, Output Cost, Context Length, AA Coding Index, Cached Input Cost, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.