GPT-5.5 vs Mistral Small
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GPT-5.5 specs · Mistral Small specs- PriceMistral Small
Mistral Small 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 1 for Mistral Small.
- OpennessMistral Small
Mistral Small ships open weights (Apache-2.0); GPT-5.5 is API-only.
It's a genuine coin-flip between GPT-5.5 and Mistral Small: 2 category wins each, with the rest tied. Mistral Small 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-5.5 handles text, vision, audio while Mistral Small handles text, which can be the deciding factor before you even look at benchmarks. Mistral Small ships open weights (Apache-2.0); GPT-5.5 is API-only.
GPT-5.5 is the newer of the two, released 18 months after Mistral Small, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-5.5 is usually picked for agents and tool use workloads, while Mistral Small sees more deployments in cheapest llm and fastest llm. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GPT-5.5 | Mistral Small |
|---|---|---|
| Provider | OpenAI | Mistral |
| Released | Mar 2026 | Sep 2024 |
| Modalities | text, vision, audio | text |
| Context window | 400K tokens | 128K tokens |
| Max output | , | , |
| Input · 1M | Pricing not published | $0.20 / 1M tokens |
| Output · 1M | Pricing not published | $0.60 / 1M tokens |
| Knowledge cutoff | , | , |
| Open weights | No | Yes (Apache-2.0) |
| 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, vs $1.50
- Heavy usage, 1M in / 500k out per day, vs $15.00
- RAG workload, 5M in / 200k out per day, vs $33.60
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-5.5Pricing unavailable
- Mistral Small$0.050
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
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 Mistral Small.
- Multimodal needs covering vision, audio.
Mistral Small fits when…
- Apache-2.0 open-weight
- Fast and cheap
- Self-hosting and on-prem requirements, open weights (Apache-2.0).
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-5.5 or Mistral Small 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 Mistral Small.Is GPT-5.5 or Mistral Small better for coding?
Both GPT-5.5 and Mistral Small 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?
Mistral Small ships open weights (Apache-2.0). GPT-5.5 is API-only.When were GPT-5.5 and Mistral Small released?
GPT-5.5 was released by OpenAI on 2026-03-01. Mistral Small was released by Mistral on 2024-09-18.
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