These aren't stripped-down versions of the flagship model—they're purpose-built machines designed for the kind of work where waiting half a minute for an answer is not an option.
OpenAI calls them its “most capable small models yet,” saying that GPT-5.4 Mini is more than two times faster than GPT-5 Mini. If you've ever watched a coding assistant think for 45 seconds before editing three lines of code, then you understand the appeal of a fast model.
We’re introducing GPT-5.4 mini and nano, our most capable small models yet.
GPT-5.4 mini is more than 2x faster than GPT-5 mini. Optimized for coding, computer use, multimodal understanding, and subagents.
So why would anyone release a less accurate model on purpose? The short answer: because accuracy isn't always the bottleneck. If you're running a customer service chatbot that answers the same 200 questions all day, then you don't need the model that scored best on PhD-level chemistry exams. You need the one that responds in under a second and costs a fraction of a cent per reply. That's the space these models are built for.
On OSWorld-Verified, which tests how well a model can actually operate a desktop computer by reading screenshots, Mini hit 72.1%, just shy of the flagship's 75.0%—and both clear the human baseline of 72.4%. GPT-5.4 Nano, meanwhile, scores 52.4% on SWE-Bench Pro and 39.0% on OSWorld—lower than Mini, but still a major leap over previous Nano-class models.
GPT-5.4 Mini runs at a rate of $0.75 per million input tokens and $4.50 per million output tokens via the API. GPT-5.4 Nano is even cheaper: $0.20 per million input tokens and $1.25 per million output tokens—a price point that makes running a huge amount of queries per day financially realistic for startups. For context, Nano is roughly four times cheaper than Mini on inputs.
For regular ChatGPT users, GPT-5.4 Mini is available today to Free and Go users via the "Thinking" option in the plus menu. Paid subscribers who hit their GPT-5.4 rate limits will automatically fall back to Mini. GPT-5.4 Nano, however, is API-only for now—OpenAI is clearly positioning it as a developer tool, not a consumer one.
