Head to head

GPT-5.4 vs Kimi K2.6

GPT-5.4 (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-5.4Kimi K2.6
Intelligence (AA index)5754
Output speed (tokens/sec)163.440.6
Context window1.1M256K
Max output262K
Input price / 1M$2.5$0.95
Output price / 1M$15$4
Released2026-032026-04

Choose GPT-5.4 if you want…

  • Higher intelligence (Artificial Analysis index 57)
  • Faster output (~163.4 tokens/sec)
  • Larger context window (1.1M)

Choose Kimi K2.6 if you want…

  • Lower price ($1.71 / 1M blended)

GPT-5.4

GPT-5.4 was built for the actual work that happens inside offices — financial modeling, legal analysis, complex codebases, and multi-step document workflows — rather than for chasing narrow benchmarks. That strategic shift shows in the numbers: it matched or outperformed human professionals in 83% of head-to-head comparisons, and developers have called its coding output "flawless," with some declaring it the definitive choice for complex software engineering work. Native computer-use capabilities let it operate browsers and desktop apps directly, and it scored above the human baseline on UI interaction tasks. The 1.05 million token context window handles large codebases and lengthy legal documents in a single pass, though you need to configure it explicitly — the default is 272K. Where GPT-5.4 falls short is nuance: it tends to interpret requests too literally, missing the intent behind ambiguous prompts in ways that Claude handles more naturally. Writing personality is another common frustration, with verbose follow-up suggestions that can feel mechanical. For structured professional tasks where thoroughness and tool integration matter more than prose feel, it is the strongest model in the GPT-5 line prior to the release of GPT-5.5.

Full GPT-5.4 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-5.4 or Kimi K2.6?

GPT-5.4 leads on 3 of the headline metrics (higher intelligence (artificial analysis index 57); faster output (~163.4 tokens/sec); larger context window (1.1m)), while Kimi K2.6 wins on lower price ($1.71 / 1m blended). The right pick depends on whether you prioritise capability, speed, or cost.

Is GPT-5.4 or Kimi K2.6 cheaper?

Kimi K2.6 is cheaper at $1.71 per 1M tokens (blended), versus $5.63.

Can I use both GPT-5.4 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.