Is GLM 5.3 Fast or GPT-5.3 Chat cheaper?

GLM 5.3 Fast is cheaper on output tokens ($6.60 vs $14.00 per 1M).

Which has the larger context window, GLM 5.3 Fast or GPT-5.3 Chat?

GLM 5.3 Fast has the larger context window (1M tokens).

GLM 5.3 Fast vs GPT-5.3 Chat

GLM 5.3 Fast is cheaper on output tokens, while GLM 5.3 Fast offers a larger context window. Choose GLM 5.3 Fast or GPT-5.3 Chat based on the trade-off between cost, context, and the benchmarks that matter for your use case.

Spec	GLM 5.3 Fast	GPT-5.3 Chat
Provider	Vercel AI Gateway	Vercel AI Gateway
Input / 1M tokens	$2.10	$1.75
Output / 1M tokens	$6.60	$14.00
Context window	1M	128K
Parameters	—	—
Open weights	Yes	No
Released	Aug 2026	Mar 2026

GLM 5.3 Fast details →GPT-5.3 Chat details →

FAQ

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