# OpenRouter explains open-weight versus closed-weight models with usage and price data

> Original title: Open-Weight vs Closed-Weight Models: What's the Difference?

- Source: OpenRouter Blog
- Published: 2026-10-31T00:00:00.000Z
- Bad Influence: https://badinfluence.news/items/xm5h907i5wfjqm31vfn5f0r7j
- Original: https://openrouter.ai/blog/insights/open-weight-vs-closed-weight-models/

## Summary

OpenRouter defines open-weight models as models whose trained weights are published, and says they are available from many providers rather than only the model's maker. Its data shows open-weight models handled 71.7% of top-50 model tokens in the week of September 28, 2026, and cost about a quarter as much per token.

## Why it matters

The post separates usage, price, and quality data from its own measurements, so readers can judge the open-weight trade-off against their own workload.