Is GPT-3.5-Turbo-Instruct or GPT-5.1-Codex cheaper?

GPT-3.5-Turbo-Instruct is cheaper on output tokens ($1.80 vs $9.00 per 1M).

Which has the larger context window, GPT-3.5-Turbo-Instruct or GPT-5.1-Codex?

GPT-5.1-Codex has the larger context window (400K tokens).

GPT-3.5-Turbo-Instruct vs GPT-5.1-Codex

GPT-3.5-Turbo-Instruct is cheaper on output tokens, while GPT-5.1-Codex offers a larger context window. Choose GPT-3.5-Turbo-Instruct or GPT-5.1-Codex based on the trade-off between cost, context, and the benchmarks that matter for your use case.

Spec	GPT-3.5-Turbo-Instruct	GPT-5.1-Codex
Provider	Poe	Poe
Input / 1M tokens	$1.40	$1.10
Output / 1M tokens	$1.80	$9.00
Context window	4K	400K
Parameters	20B	—
Open weights	No	No
Released	Sep 2023	Nov 2025

GPT-3.5-Turbo-Instruct details →GPT-5.1-Codex details →

FAQ

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