comparison
GPT-5.4 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 80× less.
Positioned by published specs — size, context and modality — not measured performance; a smaller model can sometimes outperform a larger one on your task.
GPT-5.4 is one class larger (Flagship vs Mid). Lean to the cheaper gpt-oss-120b unless your task is demanding enough to need the larger class.
| metric | GPT-5.4 | gpt-oss-120b |
|---|---|---|
| Input / 1M | $2.50 | $0.037 |
| Output / 1M | $15.00 | $0.17 |
| Context | 1.1M | 131K |
| Technical class | Flagship | Mid |
| Cost @ typical workload | $2,250/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's $2,250/mo — roughly 80× 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 has the larger 1.1M-token window (~1,575 pages). Only GPT-5.4 accepts image input — decisive if your prompts include images. By technical class (size and context, not measured capability), GPT-5.4 is a Flagship and gpt-oss-120b a Mid — so the lower price partly reflects a smaller class, not just a discount.
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 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 $2,250/mo for GPT-5.4 — about 80× 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 and gpt-oss-120b from OpenAI?
Same provider, different tier. On price, GPT-5.4 is $2.50/$15.00 per 1M (in/out) and gpt-oss-120b is $0.037/$0.17. By technical class (size & context) it's Flagship (GPT-5.4) versus Mid (gpt-oss-120b). GPT-5.4 carries the larger 1.1M-token context.
Why is gpt-oss-120b so much cheaper than GPT-5.4?
gpt-oss-120b has a much lower per-token rate — $0.17/1M output versus $15.00, and it's a smaller technical class (Mid vs Flagship). 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 or gpt-oss-120b?
GPT-5.4 — its 1.1M-token context window (~1,575 pages of text) is the larger of the two, by roughly 8×.
More comparisons
- GPT-5.5 vs GPT-5.4
- GPT-5.5 vs gpt-oss-120b
- GPT-5.4 vs GPT-5.4 mini
- GPT-5.4 vs GPT-5.4 nano
- Claude Fable 5 vs GPT-5.4
- Claude Opus 4.8 vs GPT-5.4
Related
- GPT-5.4 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.