GPT-5 Nano vs GPT OSS 120B vs Qwen3.5 9B

It is close. Our weighted score puts them within 2 points (Qwen3.5 9B 72/100, GPT-5 Nano 70/100, GPT OSS 120B 61/100), so choose by what matters most for your work: GPT OSS 120B for raw capability, Qwen3.5 9B on price and GPT-5 Nano for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Qwen3.5 9B is cheaper at $0.10 input / $0.15 output per million tokens (median across 14 API providers). GPT-5 Nano costs $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 $0.113 per million tokens for Qwen3.5 9B versus $0.138 for GPT-5 Nano (1.2× as much) and $0.263 for GPT OSS 120B (2.3× as much).

GPT OSS 120B scores higher on the Capabilities Index (ECI): GPT OSS 120B 140.0 (#99 of 148), Qwen3.5 9B 139.5 (#101 of 148) and GPT-5 Nano 139.4 (#102 of 148). The confidence ranges of the top two overlap (135.3–142.3 vs 136.5–141.3), so treat the gap as small. On individual benchmarks: GPQA Diamond — Qwen3.5 9B 79.0%, 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%, Qwen3.5 9B 61.7%.

There are no published SWE-bench Verified results for GPT-5 Nano, GPT OSS 120B and Qwen3.5 9B 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. All three support tool calling for agent workflows.

GPT-5 Nano has the largest context window at 400,000 tokens, against 262,144 for Qwen3.5 9B and 131,072 for GPT OSS 120B. Maximum output per response: GPT-5 Nano up to 128,000, GPT OSS 120B up to 32,768, Qwen3.5 9B up to 65,536 tokens.

GPT-5 Nano accepts text and images; GPT OSS 120B accepts text; Qwen3.5 9B accepts text, images and video. Qwen3.5 9B handles the widest range of inputs.

GPT OSS 120B and Qwen3.5 9B publishes its weights and can be self-hosted; GPT-5 Nano is proprietary.

Qwen3.5 9B is the newest, released Feb 23, 2026. GPT-5 Nano came out Aug 7, 2025; GPT OSS 120B came out Aug 5, 2025. Knowledge cutoff: GPT-5 Nano May 30, 2024.

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.