GPT-5 Nano vs GPT OSS 120B
GPT-5 Nano comes out ahead, 70 to 61 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-5 Nano
70/100- ECI139.4
- Price$0.05 / $0.40
- Context400K
- OpenAI
GPT OSS 120B
61/100- ECI140.0
- Price$0.15 / $0.60
- Context131K
Add a model
Make it a three-way comparison.
GPT-5 Nano is our pick
GPT-5 Nano is the better all-round choice, scoring 70/100 against GPT OSS 120B (61). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT OSS 120BCapabilities Index (ECI): GPT OSS 120B 140.0 · GPT-5 Nano 139.4
- Lowest priceGPT-5 NanoGPT-5 Nano $0.138 · GPT OSS 120B $0.263 per 1M tokens (3:1 blend)
- Longest contextGPT-5 NanoGPT-5 Nano 400,000 · GPT OSS 120B 131,072 tokens
- Widest inputsGPT-5 NanoGPT-5 Nano: Text, Images · GPT OSS 120B: Text
- Self-hostingGPT OSS 120BPublishes downloadable weights
| Measure | Weight | GPT-5 Nano | GPT OSS 120B |
|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 65 | 65 |
| Price | 25% | 91 | 77 |
| Inputs & features | 15% | 70 | 45 |
| Context window | 10% | 44 | 24 |
| Overall | 100% | 70/100 | 61/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5 NanoOpenAI | GPT OSS 120BOpenAI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 139.4 | 140.0 (best) |
| ECI rank | #102 of 148 | #99 of 148 (best) |
| GPQA DiamondGraduate-level science questions | 69.4% | 75.8% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 20.0% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 81.1% | 88.9% (best) |
| SimpleQA VerifiedShort factual questions | 11.7% | — |
| Price per million tokens | ||
| Input | $0.05 (best) | $0.15 |
| Output | $0.40 (best) | $0.60 |
| Cached input | $0.005 | — |
| Blended (3:1) | $0.138 (best) | $0.263 |
| Long-context rate | Same rate | Same rate |
| Price source | Official OpenAI API | Median of 36 providers |
| Limits | ||
| Context window | 400,000 tokens (best) | 131,072 tokens |
| Max output | 128,000 tokens (best) | 32,768 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | No |
| PDFs | No | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yesminimal · low · medium · high | Yes |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Open |
| API model ID | gpt-5-nano | — |
| API providers | 21 | 39 (best) |
| Released | Aug 7, 2025 | Aug 5, 2025 |
| Knowledge cutoff | May 30, 2024 | — |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5 Nano$1.30
- GPT OSS 120B$2.70
Which should you choose?
Which is better: GPT-5 Nano or GPT OSS 120B?
GPT-5 Nano is the better all-round choice, scoring 70/100 against GPT OSS 120B (61). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, GPT-5 Nano or GPT OSS 120B?
GPT-5 Nano is cheaper at $0.05 input / $0.40 output per million tokens (official OpenAI API price). GPT OSS 120B costs $0.15 input / $0.60 output per million tokens (median across 36 API providers). At a typical mix of three input tokens to one output token, that is $0.138 per million tokens for GPT-5 Nano versus $0.263 for GPT OSS 120B (1.9× as much).
Which scores higher on benchmarks?
GPT OSS 120B scores higher on the Capabilities Index (ECI): GPT OSS 120B 140.0 (#99 of 148) and GPT-5 Nano 139.4 (#102 of 148). The confidence ranges of the top two overlap (135.3–142.3 vs 134.9–141.7), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT OSS 120B 75.8%, GPT-5 Nano 69.4%; OTIS Mock AIME 2024–2025 — GPT OSS 120B 88.9%, GPT-5 Nano 81.1%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5 Nano and GPT OSS 120B yet, so there is no like-for-like coding score. On overall capability, GPT OSS 120B leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.
Which has the bigger context window?
GPT-5 Nano has the largest context window at 400,000 tokens, against 131,072 for GPT OSS 120B. Maximum output per response: GPT-5 Nano up to 128,000, GPT OSS 120B up to 32,768 tokens.
Which can read images, PDFs, audio or video?
GPT-5 Nano accepts text and images; GPT OSS 120B accepts text. GPT-5 Nano handles the widest range of inputs.
Are any of these open source?
GPT OSS 120B publishes its weights and can be self-hosted; GPT-5 Nano is proprietary.
Which is newer?
GPT-5 Nano is the newest, released Aug 7, 2025. GPT OSS 120B came out Aug 5, 2025. Knowledge cutoff: GPT-5 Nano May 30, 2024.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
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