GPT-5 vs gpt-oss-120b
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
OpenAI · Aug 2025
OpenAI's August 2025 unified flagship that merged the GPT and o-series reasoning lines into one model with selectable effort.
OpenAI · Aug 2025
OpenAI's open-weights MoE reasoning model under Apache 2.0 — near o4-mini quality, runnable on a single 80GB GPU.
The verdict
GPT-5 wins 3 of the 3 benchmarks these models share, against 0 for gpt-oss-120b. On price the gap is dramatic: gpt-oss-120b works out roughly 17x cheaper per blended million tokens. GPT-5 also takes 400K of context versus 131K for gpt-oss-120b. And gpt-oss-120b is open-weights (Apache 2.0), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
Benchmark head-to-head 3–0
Specs & pricing
| GPT-5 | gpt-oss-120b | |
|---|---|---|
| modhub Index | 70.7 | — |
| Input price / 1M | $1.25 | $0.1 |
| Output price / 1M | $10 | $0.5 |
| Context window | 400K | 131K |
| Max output | 128K | 131K |
| Open weights | no | yes (Apache 2.0) |
| Reasoning model | yes | yes |
| Multimodal input | text, image | text |
| Knowledge cutoff | Sep 2024 | Jun 2024 |
| Released | Aug 2025 | Aug 2025 |
| Example monthly cost* | $27.50 | $1.75 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GPT-5 or gpt-oss-120b?
- GPT-5 wins 3 of the 3 benchmarks these models share, against 0 for gpt-oss-120b. On price the gap is dramatic: gpt-oss-120b works out roughly 17x cheaper per blended million tokens. GPT-5 also takes 400K of context versus 131K for gpt-oss-120b. And gpt-oss-120b is open-weights (Apache 2.0), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
- Which is cheaper, GPT-5 or gpt-oss-120b?
- GPT-5 costs $1.25/$10 per million input/output tokens, while gpt-oss-120b costs $0.1/$0.5. For a typical workload of 10M input and 1.5M output tokens per month, that's $27.50 versus $1.75.
- Which model is better for coding, GPT-5 or gpt-oss-120b?
- We don't yet track SWE-bench Verified results for both models; check their individual pages for coding-related scores.