# 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), a day after API/Codex mini+nano. API: $0.75/$4.50 per 1M in/out, 400k context. Lab benches (high/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** made **GPT-5.4 mini** available in ChatGPT (March 18) to **Free and Go** users via the **Thinking** option (+ menu). API and Codex mini/nano landed March 17; 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, high/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** at stated effort levels — independent Artificial Analysis / Arena Elo not required for this ChatGPT-surface story but should be checked before ranking freezes.

## Limits

- Free/Go Thinking quotas still apply.
- Effort-skewed benches are not default-chat Elo.
- Nano economics differ; do not conflate mini with nano.

## Sources

- [OpenAI: “Introducing GPT-5.4 mini and nano”](https://openai.com/index/introducing-gpt-5-4-mini-and-nano) (March 17, 2026).
- [OpenAI Help: Model Release Notes — GPT-5.4 mini in ChatGPT](https://help.openai.com/en/articles/9624314-model-release-notes) (March 18, 2026).
- Community and benchmark tracking confirming rollout timing.