O3 Mini
OpenAI | 200,000 token context | $1.10/M input, $4.40/M output. OpenAI o3-mini is a cost-efficient language model optimized for STEM reasoning tasks, particularly excelling in science, mathematics, and coding. This model supports the reasoning_effort parameter, which can be set to "high", "medium", or "low" to control the thinking time of the model. The default is "medium". OpenRouter also offers the model slug openai/o3-mini-high to default the parameter to "high". The model features three adjustable reasoning effort levels and supports key developer capabilities including function calling,…OpenAI | 200,000 token context | $1.10/M input, $4.40/M output. OpenAI o3-mini is a cost-efficient language model optimized for STEM reasoning tasks, particularly excelling in science, mathematics, and coding. This model supports the reasoning_effort parameter, which can be set to "high", "medium", or "low" to control the thinking time of the model. The default is "medium". OpenRouter also offers the model slug openai/o3-mini-high to default the parameter to "high". The model features three adjustable reasoning effort levels and supports key developer capabilities including function calling, structured outputs, and streaming, though it does not include vision processing capabilities. The model demonstrates significant improvements over its predecessor, with expert testers preferring its responses 56% of the time and noting a 39% reduction in major errors on complex questions. With medium reasoning effort settings, o3-mini matches the performance of the larger o1 model on challenging reasoning evaluations like AIME and GPQA, while maintaining lower latency and cost.
Captain's notes
Known for
- Three reasoning effort levels let you trade speed and cost against answer quality.
- Matches o1 on AIME and GPQA math and science benchmarks at medium effort.
- 39% fewer major errors on complex questions compared to its predecessor.
- Full developer toolkit: function calling, structured outputs, and streaming.
- 200,000-token context window handles long codebases and technical documents.
Watch out for
- No vision support — it cannot process images, so multimodal tasks need a different model.
- Weights are closed; you rent access via API and cannot run it locally.
- Output tokens cost four times the input rate, so verbose reasoning chains add up.
Prompts to try
Compare with
- gpt-oss-120bOpen-weights model131,072 token context · $0.15/M input, $0.60/M output
- gpt-oss-20bOpen-weights model131,072 token context · $0.02/M input, $0.09/M output
- GPT-5.6 SolAPI-only model1,050,000 token context · $4.00/M input, $20.00/M output
- GPT-6.1 SolAPI-only model1,050,000 token context · $2.00/M input, $10.00/M output
Questions people ask
- Can I run o3-mini locally or download the weights?
- No. o3-mini is an API-only model from OpenAI; the weights are not public and there is no way to run it on your own hardware.
- What does o3-mini cost and how large is its context?
- It costs $1.10 per million input tokens and $4.40 per million output tokens, with a 200,000-token context window.
- How does o3-mini differ from o1 and from o3?
- o3-mini is smaller and cheaper than both, but at medium reasoning effort it matches o1 on hard math and science benchmarks; it trades some ceiling for lower latency and cost, and it adds the reasoning_effort parameter that o1 does not expose.
Captain's verdictThe reasoning effort dial is the real selling point: sensible default, easy to crank up when a problem earns it.
Glossary: the terms used here
- Heat score
- One number for how much a model is used and wanted right now, from 0° to 9,999°. Every list on this site that says hottest is sorted by it and nothing else.
- Floor
- The 7,000° every model with real data starts from. The scale runs from 0° to 9,999°; the part below the floor is reserved for stand-ins (models without data), so that a model with data always ranks above one without. The floor is the same for everyone and decides nothing; the degrees above it are the measurement.
- Download-equivalents
- Everything the score treats as a download, added up: downloads themselves, each torrent seeder as 1,000, each AI Horde image and each run on a generation site as one.
- Log scale
- Counting by tens, not by ones: going from 1,000 to 10,000 downloads adds the same degrees as going from 10,000 to 100,000. It keeps giants from crowding out everything else.
- Likes
- Thumbs up and likes from every source, worth half a download each on the log scale.
- Adoption rate
- How many downloads a day a model gets right now, from the difference between two readings of a source. A quarter of the weight of the download term.
- Measured and estimated
- Measured means two readings of a source exist and the difference is real. Estimated means only today's total is known and the past is spread over the model's life; the site says which one it is showing.
- Seeder
- Someone who keeps a copy of the weights online for others to download over a torrent, or a hosted mirror doing the same. Each one counts as 1,000 downloads.
- AI Horde
- A volunteer network that generates images for free on donated computers. The number of images it has made with a model is public, and each counts as one download.
- Generation sites
- Sites that host their own copies of a model and let people generate with it, such as PixAI, SeaArt and Yodayo. Their downloads count like Civitai's and each generation run as one download.
- OpenRouter tokens
- A text model served through an API, such as Claude or GPT, has no weights to download, so its usage is measured in tokens: the pieces of text it read and wrote through OpenRouter, a gateway many apps use, over the last 30 days. Every 10,000,000 tokens count as one download. Source: OpenRouter (openrouter.ai/rankings), CC BY 4.0.
- Full model (checkpoint)
- The weights themselves, the file that generates on its own. It gets a bonus because add-ons depend on it.
- LoRA and embedding
- Small add-on files that steer someone else's weights toward a style, a character or a concept. They cannot run alone.
- Family and weights
- The base a model is built on, such as SD 1.5, SDXL, Flux or Wan. Every model inherits the release date of its family's weights.
- Age
- Degrees taken off for how long ago the family's weights came out: 150° a year, up to 750°. It keeps old downloads that had years to pile up from freezing the top of the list.
- Family boost
- A small, bounded nudge for LoRAs of a family this site is pushing forward right now, always listed in the breakdown.
- Stand-in score
- A stable number below the floor given to a model no source reports on yet, so lists stay complete. It never ranks above a model with data.
- New! (grace period)
- A model less than 7 days old shows New! instead of a score and holds no place in the rankings. Its score is computed from day one, but a model one day old grows faster than anything, so without the wait the week's #1 would always be whatever came out yesterday rather than what held up for a week.
- Trend
- How a model's growth over a period compares with the typical model's growth over the same period. Faster than typical reads as a rise, slower as a fall.
- Typical model
- The middle of the catalog: half the models with a figure grew faster over the period, half slower.
