GPT-5 mini vs o3
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GPT-5 mini specs · o3 specs- PriceGPT-5 mini
GPT-5 mini is roughly 4.0× cheaper on output tokens ($2.00 vs $8.00 per 1M).
- Context windowGPT-5 mini
GPT-5 mini accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.
- BenchmarksTie
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores.
- ModalitiesGPT-5 mini
GPT-5 mini supports 3 modalities (text, vision, audio) vs 2 for o3.
- OpennessTie
Both are closed-weight, API-only.
On balance GPT-5 mini edges ahead, winning 3 of 5 categories against o3's 0. GPT-5 mini is roughly 4.0× cheaper on output tokens ($2.00 vs $8.00 per 1M). GPT-5 mini accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. They differ in modality coverage, GPT-5 mini handles text, vision, audio while o3 handles text, vision, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.
GPT-5 mini is the newer of the two, released 4 months after o3, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-5 mini is usually picked for code completion and customer support workloads, while o3 sees more deployments in reasoning and math. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GPT-5 mini | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Released | Aug 2025 | Apr 2025 |
| Modalities | text, vision, audio | text, vision |
| Context window | 400K tokens | 200K tokens |
| Max output | 128K tokens | , |
| Input · 1M | $0.25 / 1M tokens | $2.00 / 1M tokens |
| Output · 1M | $2.00 / 1M tokens | $8.00 / 1M tokens |
| Knowledge cutoff | 2024-09 | 2024-06 |
| Open weights | No | No |
| API available | Yes | Yes |
Pricing at scale
What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.
- Light usage, 100k in / 50k out per day$3.75 vs $18.00
- Heavy usage, 1M in / 500k out per day$37.50 vs $180
- RAG workload, 5M in / 200k out per day$49.50 vs $348
Light usage, 100k in / 50k out per day: $3.75 vs $18.00 per month, model A comes out ahead. Heavy usage, 1M in / 500k out per day: $37.50 vs $180 per month, model A comes out ahead. RAG workload, 5M in / 200k out per day: $49.50 vs $348 per month, model A comes out ahead.
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- GPT-5 mini$0.125
- o3$0.600
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
- HumanEval,95.0
- GPQA,87.7
GPT-5 mini fits when…
- Excellent price-quality ratio for production workloads
- Fast first-token latency
- Same tool-use API surface as flagship
- Cost-sensitive workloads, 4.0× cheaper than o3 on output tokens.
- Long-context tasks, handles 400K tokens vs 200K for o3.
o3 fits when…
- Industry-leading reasoning depth at launch
- Strong on math, science, and abstract puzzles
- Tool-use during reasoning loops
Consider GPT-5.5
OpenAI's mid-cycle GPT-5 refresh, improved reasoning, tool use, and multimodal grounding over the 2025 launch.
Frequently asked
Is GPT-5 mini or o3 cheaper?
GPT-5 mini is cheaper at $2.00 / 1M tokens per million output tokens, vs $8.00 / 1M tokens for o3.Which has the larger context window?
GPT-5 mini accepts 400K tokens vs 200K for o3.Is GPT-5 mini or o3 better for coding?
Both GPT-5 mini and o3 are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.Are either of these models open source?
Neither model ships open weights, both are accessible only via their respective providers' APIs.When were GPT-5 mini and o3 released?
GPT-5 mini was released by OpenAI on 2025-08-07. o3 was released by OpenAI on 2025-04-16.
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