comparison
GPT-5.4 mini vs gpt-oss-120b
Token pricing, context window and real monthly cost, side by side. gpt-oss-120b is the cheaper of the two for a typical workload — about 24× less.
Positioned by published specs — size, context and modality — not measured performance; a smaller model can sometimes outperform a larger one on your task.
By size & context, gpt-oss-120b (Mid) sits above GPT-5.4 mini (Mini) yet costs less. On spec it's the straightforward pick; choose GPT-5.4 mini only for something it offers that gpt-oss-120b doesn't — modality, provider or ecosystem.
| metric | GPT-5.4 mini | gpt-oss-120b |
|---|---|---|
| Input / 1M | $0.75 | $0.037 |
| Output / 1M | $4.50 | $0.17 |
| Context | 400K | 131K |
| Technical class | Mini | Mid |
| Cost @ typical workload | $675/mo | $28.10/mo |
| Modality | text + image | Text only |
| Price source | list | routed |
| Provider | OpenAI | OpenAI |
Snapshot . Cost uses a typical workload; tune it in the calculator. How we measure →
Which should you pick?
On a typical workload, gpt-oss-120b costs $28.10/mo against GPT-5.4 mini's $675/mo — roughly 24× cheaper. But the ranking depends on your output-to-input ratio: output is the pricier direction for both, so an output-heavy job (code generation, long answers) widens the gap while an input-heavy one (summarization, retrieval) narrows it. If you need to fit more in a single prompt, GPT-5.4 mini has the larger 400K-token window (~600 pages). Only GPT-5.4 mini accepts image input — decisive if your prompts include images. By technical class (size and context, not measured capability), gpt-oss-120b is the larger class (Mid) and the cheaper of the two — on spec, the stronger pick here.
These are list and routed market prices, not measured outcomes. Two models at the same rate can still cost different amounts to finish the same task, because verbose or reasoning-heavy models emit more tokens. That gap is exactly what measured cost-per-task captures. The technical-class read above is likewise spec-based — size, context and modality, not measured performance — so a smaller model can still outperform a larger one on your specific task.
Frequently asked questions
Is GPT-5.4 mini or gpt-oss-120b cheaper?
For a typical workload (1,500 input + 500 output tokens × 200,000 requests/month), gpt-oss-120b costs $28.10/mo versus $675/mo for GPT-5.4 mini — about 24× less. Because output is priced higher than input, the winner can flip if your workload writes much more or less than this; check your own numbers in the calculator.
What's the difference between GPT-5.4 mini and gpt-oss-120b from OpenAI?
Same provider, different tier. On price, GPT-5.4 mini is $0.75/$4.50 per 1M (in/out) and gpt-oss-120b is $0.037/$0.17. By technical class (size & context) it's Mini (GPT-5.4 mini) versus Mid (gpt-oss-120b). GPT-5.4 mini carries the larger 400K-token context.
Why is gpt-oss-120b so much cheaper than GPT-5.4 mini?
gpt-oss-120b has a much lower per-token rate — $0.17/1M output versus $4.50, and it's a smaller technical class (Mid vs Mini). The headline rate isn't the whole story, though: a verbose model can cost more to finish a task than its rate implies — that's what measured cost-per-task captures.
Which handles longer prompts, GPT-5.4 mini or gpt-oss-120b?
GPT-5.4 mini — its 400K-token context window (~600 pages of text) is the larger of the two, by roughly 3×.
More comparisons
- GPT-5.5 vs GPT-5.4 mini
- GPT-5.5 vs gpt-oss-120b
- GPT-5.4 vs GPT-5.4 mini
- GPT-5.4 vs gpt-oss-120b
- GPT-5.4 mini vs GPT-5.4 nano
- Claude Sonnet 4.6 vs GPT-5.4 mini
Related
- GPT-5.4 mini and gpt-oss-120b — full specs and price history.
- API cost calculator — compare on your own workload.
- All comparisons — the full head-to-head index.