GPT-5 mini Review: Specs, Pricing & Best Use Cases

GPT-5 mini is the smaller, cheaper version of GPT-5 that OpenAI released alongside the full model on August 7, 2025. It keeps most of GPT-5's reasoning ability at a fifth of the price, which made it a popular default for everyday chat, summaries, and high-volume apps where speed and cost matter more than maximum depth.

This GPT-5 mini review covers what the model is, how its benchmarks compare with the full GPT-5, what it costs, how it stacks up against newer budget models, and when it is the right pick. GPT-5 mini is available in Chat Smith on Android, iOS, and the web, so you can try it without an OpenAI account.

GPT-5 mini is the middle size in OpenAI's GPT-5 family, between the full model and GPT-5 nano. Like the full model covered in our GPT-5 review, it is a reasoning model, so it can think through a problem before it answers. It is simply smaller, which makes it faster and much cheaper to run.

It shares GPT-5's 400,000-token context window, accepts text and images, and returns text. Developers can set its reasoning effort from minimal to high and control how long its answers are. Its training data runs to May 2024, a few months earlier than the full GPT-5.

In ChatGPT, GPT-5 mini mainly worked behind the scenes, taking over when free users reached their GPT-5 limit. The GPT-5 models left ChatGPT in February 2026, but GPT-5 mini is still available in the OpenAI API. For even lighter workloads, OpenAI also offers GPT-5 nano.

Four strengths explain why GPT-5 mini became a common default model.

On OpenAI's launch benchmarks at high reasoning effort, GPT-5 mini scored 91.1% on the AIME 2025 math competition and 82.3% on GPQA Diamond, only a few points behind the full GPT-5. For homework help, quick calculations, and step-by-step explanations, the kind of work an AI math solver handles, that gap rarely shows.

GPT-5 mini reached 71.0% on SWE-bench Verified, a test built from real GitHub issues, compared with 74.9% for the full GPT-5. That made it a cost-effective choice for developers running many smaller coding tasks, such as explaining snippets, writing tests, or fixing straightforward bugs.

GPT-5 mini scored 81.6% on MMMU, a benchmark of reasoning over images, charts, and diagrams, close to the full model's 84.2%. In practice, it can read screenshots, describe photos, pull numbers from charts, and answer questions about what an image shows.

With reasoning effort set to minimal, GPT-5 mini answers almost instantly, which suits chat, rewrites, and short summaries. When a question needs more care, the same model can think longer. That flexibility makes it a practical engine for an AI summarizer or any app that handles many requests a day.

The table compares GPT-5 mini with the full model it was cut down from and with GPT-6 Luna, OpenAI's newest budget model. GPT-5 scores are OpenAI's launch figures at high reasoning effort; OpenAI reported GPT-6 Luna on newer benchmarks, so its scores are not directly comparable.

GPT-5 mini delivers most of GPT-5's quality at a fifth of the price, while GPT-6 Luna now undercuts it on cost and offers a much larger context window. Our GPT-6 Luna review covers the newer model, and our GPT-4o mini guide covers the small model GPT-5 mini replaced.

In the OpenAI API, GPT-5 mini costs $0.25 per million input tokens and $2 per million output tokens, with cached input 90% cheaper. Here is where you can use it:

In Chat Smith, you can use GPT-5 mini without an OpenAI account. Free accounts include limited use, and Chat Smith Pro raises usage limits for $9.99 per month or $39.99 per year.

GPT-5 mini trails the full GPT-5 on the hardest multi-step problems, and the gap is larger on tough research and analysis than the headline scores suggest. Its knowledge also stops in May 2024, so recent events need web search or a newer model.

It is also no longer OpenAI's newest budget option. GPT-6 Luna costs less per token and handles far longer inputs, so GPT-5 mini mainly makes sense when you already rely on its behavior or prefer it for a specific task. Our full list of ChatGPT models shows how the lineup has changed.

Finally, a low price per token does not always mean a cheap task. At high reasoning effort, GPT-5 mini can use many thinking tokens, and its benchmark scores come from OpenAI's own testing, so check it on your real workload.

GPT-5 mini is available in Chat Smith on Android, iOS, and the web. Pick it from the model list and start chatting, with no OpenAI account or ChatGPT subscription needed.

Use GPT-5 mini for quick questions, drafts, and summaries. When a task needs more depth, switch to GPT-5 in the same chat, or try GPT-6 Luna for OpenAI's newest budget model.

You can also put the same prompt to fast models from other labs, such as Gemini 3.5 Flash, and keep the answer that holds up. For research-heavy questions, the built-in Deep Research feature runs advanced search and reasoning across sources.

GPT-5 mini proved that a small model could reason well: strong math and science scores, capable coding, good image understanding, and adjustable speed, all at a fraction of GPT-5's price. It remains a dependable choice for everyday questions, drafting, and summaries.

For harder problems, step up to GPT-5 or a newer model, and for the lowest cost, look at GPT-6 Luna. You can try all of them side by side in Chat Smith, an AI chatbot that puts OpenAI's models next to the latest from Anthropic, Google, xAI, and DeepSeek.