Is GPT OSS 20B or GPT-5 cheaper?

GPT OSS 20B is cheaper on output tokens ($0.20 vs $10.00 per 1M).

Which has the larger context window, GPT OSS 20B or GPT-5?

GPT-5 has the larger context window (400K tokens).

GPT OSS 20B vs GPT-5

GPT OSS 20B is cheaper on output tokens, while GPT-5 offers a larger context window. Choose GPT OSS 20B or GPT-5 based on the trade-off between cost, context, and the benchmarks that matter for your use case.

Spec	GPT OSS 20B	GPT-5
Provider	FastRouter	FastRouter
Input / 1M tokens	$0.05	$1.25
Output / 1M tokens	$0.20	$10.00
Context window	131K	400K
Parameters	21B	—
Open weights	Yes	No
Released	Aug 2025	Aug 2025

GPT OSS 20B details →GPT-5 details →

FAQ

Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.