GPT-4o mini vs GPT-5.5
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GPT-4o mini specs · GPT-5.5 specs- PriceGPT-4o mini
GPT-4o mini publishes pricing ($0.60 / 1M output tokens) while GPT-5.5 does not.
- Context windowGPT-5.5
GPT-5.5 accepts 400K tokens vs 128K, 3.1× 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-5.5
GPT-5.5 supports 3 modalities (text, vision, audio) vs 2 for GPT-4o mini.
- OpennessTie
Both are closed-weight, API-only.
On balance GPT-5.5 edges ahead, winning 2 of 5 categories against GPT-4o mini's 1. GPT-4o mini publishes pricing ($0.60 / 1M output tokens) while GPT-5.5 does not. GPT-5.5 accepts 400K tokens vs 128K, 3.1× 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-4o mini handles text, vision while GPT-5.5 handles text, vision, audio, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.
GPT-5.5 is the newer of the two, released 20 months after GPT-4o mini, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-4o mini is usually picked for customer support and summarization workloads, while GPT-5.5 sees more deployments in agents and tool use. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GPT-4o mini | GPT-5.5 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Released | Jul 2024 | Mar 2026 |
| Modalities | text, vision | text, vision, audio |
| Context window | 128K tokens | 400K tokens |
| Max output | , | , |
| Input · 1M | $0.15 / 1M tokens | Pricing not published |
| Output · 1M | $0.60 / 1M tokens | Pricing not published |
| Knowledge cutoff | , | , |
| 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$1.35 vs ,
- Heavy usage, 1M in / 500k out per day$13.50 vs ,
- RAG workload, 5M in / 200k out per day$26.10 vs ,
Light usage, 100k in / 50k out per day: pricing not directly comparable (one or both models are missing public per-token rates). Heavy usage, 1M in / 500k out per day: pricing not directly comparable (one or both models are missing public per-token rates). RAG workload, 5M in / 200k out per day: pricing not directly comparable (one or both models are missing public per-token rates).
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- GPT-4o mini$0.045
- GPT-5.5Pricing unavailable
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
- MMLU82.0
GPT-4o mini fits when…
- Cheap
- Fast
- Mature
GPT-5.5 fits when…
- Industry-leading tool-use and function-calling reliability
- Strong end-to-end agent performance across SWE-bench and GAIA
- Wide ecosystem support, ChatGPT, Realtime API, Responses API
- Long-context tasks, handles 400K tokens vs 128K for GPT-4o mini.
- Multimodal needs covering audio.
Consider GPT-5
OpenAI's unified flagship combining GPT-line breadth with built-in reasoning, replacing both GPT-4o and the o-series for most users.
Frequently asked
Is GPT-4o mini or GPT-5.5 cheaper?
Per-token pricing isn't published for at least one of these models, check each model's spec page for current rates.Which has the larger context window?
GPT-5.5 accepts 400K tokens vs 128K for GPT-4o mini.Is GPT-4o mini or GPT-5.5 better for coding?
Both GPT-4o mini and GPT-5.5 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-4o mini and GPT-5.5 released?
GPT-4o mini was released by OpenAI on 2024-07-18. GPT-5.5 was released by OpenAI on 2026-03-01.
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