Head to head

GPT-5 vs Kimi K2.6

GPT-5 (OpenAI) and Kimi K2.6 (Moonshot AI) compared on intelligence, speed, context, and price — and which to choose. Both run on just4o.chat from one chat.

MetricGPT-5Kimi K2.6
Intelligence (AA index)4554
Output speed (tokens/sec)100.140.6
Context window400K256K
Max output262K
Input price / 1M$1.25$0.95
Output price / 1M$10$4
Released2025-08-072026-04

Choose GPT-5 if you want…

  • Faster output (~100.1 tokens/sec)
  • Larger context window (400K)

Choose Kimi K2.6 if you want…

  • Higher intelligence (Artificial Analysis index 54)
  • Lower price ($1.71 / 1M blended)

GPT-5

GPT-5 is OpenAI's unified flagship — a single model that scales its reasoning effort up or down to match the task, rather than making you pick a separate variant. The result shows up most clearly in hard technical work: a perfect AIME 2025 score with tools, 74.9% on SWE-bench Verified, and a 1.6% error rate on medical benchmark HealthBench make it one of the more capable models available for code, math, and domain-specific research. Its 400,000-token context window handles large codebases and lengthy documents without truncation. Users consistently praise the step-up in accuracy and the meaningful reduction in hallucinations over GPT-4o. The honest caveat: GPT-5 trades warmth for precision. Early adopters widely noted that responses are shorter, cooler, and noticeably less conversational than its predecessor — a real shift if personality and back-and-forth rapport matter to your workflow. Latency is also substantial; extended reasoning produces a time-to-first-token around 68 seconds, which rules it out for anything requiring snappy replies.

Full GPT-5 details →

Kimi K2.6

Kimi K2.6 is Moonshot AI's open-weight coding specialist built for the kind of work that takes hours, not seconds. Its signature capability is agent swarm orchestration — coordinating up to 300 sub-agents across 4,000 execution steps — enabling autonomous refactoring sessions that developers have run for over 13 hours straight. On SWE-Bench Verified it scores 80.2%, and it edges out GPT-5.4 on SWE-Bench Pro at 58.6%, making it the strongest open-weight coding model available at its price point. Users report up to 88% cost savings on coding workloads compared to proprietary alternatives, which is the real draw for teams running code-heavy pipelines at scale. The tradeoff is speed and occasional drift: at 40.6 tokens per second — well below the category median — it is not suited to real-time use. In long-running agentic tasks, users note the model can wander into unnecessary redesigns around the three-hour mark, requiring clear, constrained prompting to keep it on track. For deep, non-interactive coding work where cost efficiency and open-weight flexibility matter more than instant responses, K2.6 occupies a position few models can match.

Full Kimi K2.6 details →

FAQ

Which is better, GPT-5 or Kimi K2.6?

GPT-5 leads on 2 of the headline metrics (faster output (~100.1 tokens/sec); larger context window (400k)), while Kimi K2.6 wins on higher intelligence (artificial analysis index 54); lower price ($1.71 / 1m blended). The right pick depends on whether you prioritise capability, speed, or cost.

Is GPT-5 or Kimi K2.6 cheaper?

Kimi K2.6 is cheaper at $1.71 per 1M tokens (blended), versus $3.44.

Can I use both GPT-5 and Kimi K2.6?

Yes. Both are available on just4o.chat from a single chat — you can switch between them per message with no separate subscriptions.