Head-to-head comparison
Nemotron 3 Nano 30B A3B (NVIDIA) and gpt-oss-20b (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.
Snapshot as of 15 September 2026
As of 15 September 2026, gpt-oss-20b holds the stronger ModelCap Index position (#161 vs #168); gpt-oss-20b is 1.5× cheaper per output token ($0.13/1M vs $0.20/1M); Nemotron 3 Nano 30B A3B offers the longer context window (262K vs 131K tokens); and gpt-oss-20b ships open weights.
Evidence: 2 public benchmark observations across 2 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.
Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.
Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.
gpt-oss-20b ranks higher on the ModelCap Index as of 15 September 2026: #161 against #168. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.
gpt-oss-20b is cheaper on output tokens: $0.13/1M against $0.20/1M. Input tokens are $0.05/1M for Nemotron 3 Nano 30B A3B and $0.03/1M for gpt-oss-20b. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $0.20 for Nemotron 3 Nano 30B A3B versus $0.13 for gpt-oss-20b. gpt-oss-20b costs 37.5% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.
Nemotron 3 Nano 30B A3B has the larger context window: 262K tokens against 131K.
Arena coding: Nemotron 3 Nano 30B A3B 1361, gpt-oss-20b 1369 — gpt-oss-20b leads.
Nemotron 3 Nano 30B A3B: Restricted license. gpt-oss-20b: Open weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.
ModelCap currently lists 4 API providers for Nemotron 3 Nano 30B A3B and 13 for gpt-oss-20b, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.
Every figure comes from the sealed ModelCap dataset published 15 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.