# GPT-5.4 Mini Hits ChatGPT Free/Go — Efficiency Tier, Lab Benches

Times of AI Desk · 2026-03-18 · Models

[https://timesof.ai/2026/03/openai-releases-gpt-5-4-mini-in-chatgpt](https://timesof.ai/2026/03/openai-releases-gpt-5-4-mini-in-chatgpt)

> OpenAI put GPT-5.4 mini in ChatGPT Thinking for Free and Go users (March 18), following the March 17 mini/nano announcement. API: $0.75/$4.50 per 1M in/out, 400k context. Mini lab benches (xhigh): SWE-Bench Pro 54.4%, OSWorld-Verified 72.1%, GPQA Diamond 88.0% — vendor numbers; also rate-limit fallback for higher tiers.

Flagship releases get the headlines; **mini** is how OpenAI fills Free/Go and rate-limit gaps. The trade: most of the 5.4 coding/reasoning story at lower latency and cost — **lab benches still OpenAI’s**.

**OpenAI** documented the **GPT-5.4 mini** ChatGPT rollout in March 18 release notes to **Free and Go** users via the **Thinking** option (+ menu). The March 17 launch post introduced mini across API, Codex and ChatGPT, with nano API-only; the GPT-5.4 family (Thinking/Pro) launched March 5. Mini targets responsive coding assistants, subagents, computer-use agents, and multimodal apps; also acts as rate-limit fallback for GPT-5.4 Thinking on higher tiers. Nano remains API-only at lower pricing.

| Claim (OpenAI, mini at xhigh) | Figure |
|----------------------------|--------|
| **SWE-Bench Pro (Public)** | 54.4% |
| **OSWorld-Verified** | 72.1% |
| **GPQA Diamond** | 88.0% |
| **API price** | $0.75 / $4.50 per 1M in/out |
| **Context** | 400k |
| **I/O** | Text/image; tools, function calling, web/file search, computer use, skills |

## Claims vs checks

Availability and pricing are **OpenAI primary** (blog March 17; Help Center release notes March 18). Benchmarks are **vendor-reported** at the stated effort levels; they do not establish an independent Artificial Analysis or Arena ranking.

## Limits

- Free/Go Thinking quotas still apply.
- Effort-skewed benches are not default-chat Elo.
- Mini and Nano have different economics.

**Correction (October 14, 2026):** Clarified that nano was API-only, specified xhigh for the cited mini results, and distinguished the March 17 announcement from March 18 release notes.

## Sources

- [OpenAI: Introducing GPT-5.4 mini and nano (March 17, 2026)](https://openai.com/index/introducing-gpt-5-4-mini-and-nano)
- [OpenAI: Model Release Notes, March 18, 2026 entry](https://help.openai.com/en/articles/9624314-model-release-notes)
- [OpenAI: GPT-5.4 launch (March 5, 2026)](https://openai.com/index/introducing-gpt-5-4/)