OpenAI Introduces GPT-5.4 Mini and Nano for Free ChatGPT Users
Key Points
- OpenAI released GPT-5.4 mini and GPT-5.4 nano as its most capable small models.
- The models are available to free and Go‑tier ChatGPT users via a new "Thinking" option.
- Thinking mode prioritizes multi‑step reasoning and detailed explanations.
- Tests showed Thinking responses were richer and more explanatory than standard ChatGPT answers.
- Mini and nano models are faster but slightly less deep than the full GPT-5.4 Thinking model for Plus users.
- The upgrade provides free users with a noticeable boost in answer quality and reasoning ability.
OpenAI has launched two new lightweight models, GPT-5.4 mini and GPT-5.4 nano, described as its most capable small models yet. The models are accessible to free and Go-tier ChatGPT users through a new “Thinking” option rather than a direct model selector. In testing, the Thinking models produced more detailed, multi‑step answers than the standard ChatGPT response, offering clearer reasoning for travel planning and online‑income strategies. While slightly less deep than the full‑size GPT-5.4 Thinking model available to Plus users, the mini and nano versions are faster and provide a notable upgrade for free users.
New Small‑Scale Models From OpenAI
OpenAI announced the release of two new AI models, GPT-5.4 mini and GPT-5.4 nano, branding them as the company’s “most capable small models yet.” Unlike previous releases that were limited to paid tiers, these models are now available to anyone using the free or Go version of ChatGPT. Users do not select the models directly; instead they activate a new “Thinking” tool in the Plus (+) menu, which runs the mini or nano models behind the scenes.
How the Thinking Tool Works
The Thinking option is designed for queries that benefit from careful reasoning, multiple steps, or nuanced explanations rather than quick factual recall. When activated, the system switches from the standard ChatGPT engine to the lightweight GPT-5.4 mini or nano models, delivering answers that aim to be more thoughtful and detailed.
Hands‑On Testing
The author tested the new models with two complex prompts. The first asked for a five‑day European trip on a limited budget, requesting minimized travel time and inclusion of three specific cities. The standard ChatGPT response was concise and bullet‑pointed, while the Thinking version offered a richer itinerary, explaining the rationale behind each route and choice.
The second prompt requested a realistic plan to generate online income with a modest starting fund, no coding experience, and a six‑month timeline. Again, the standard model produced a brief outline, whereas the Thinking model detailed risk analysis, timelines, and parallel strategies, providing a more concrete and trustworthy roadmap.
Comparison With the Full‑Size GPT‑5.4 Thinking Model
For Plus subscribers, the full GPT-5.4 Thinking model remains available. In side‑by‑side comparisons, the mini and nano versions delivered answers that were strikingly similar in content but arrived more quickly. The full model added extra depth and a more personalized tone, but the core reasoning and recommendations were essentially the same. This suggests that the new small models deliver a substantial portion of the full model’s capability without the same computational cost.
Implications for Free Users
The rollout means that free ChatGPT users now have access to a level of reasoning previously reserved for paid tiers. While there is a modest trade‑off in depth, the speed boost and enhanced answer quality represent a meaningful improvement over the baseline free experience. The author expresses optimism that Plus users will soon receive the mini and nano models as well, further narrowing the gap between free and paid tiers.