Compare models

Put up to 4 models beside each other — token prices, context windows, capabilities and provider, from the same catalogue the model pages read.

GPT-6 LunaOpenAI Remove
GPT-6 Luna ProOpenAI Remove
S2 ProFish Audio Remove
Perceptron Mk1.5Perceptron Remove

4 is the maximum. Remove one to add another.

gpt-6-luna vs gpt-6-luna-pro vs s2-pro vs perceptron-mk1.5
Attribute	GPT-6 Lunagpt-6-luna	GPT-6 Luna Progpt-6-luna-pro	S2 Pros2-pro	Perceptron Mk1.5perceptron-mk1.5
Pricing
Input	$0.10 / 1M	$0.10 / 1M	$0 / 1M	$0.15 / 1M
Output	$0.50 / 1M	$0.50 / 1M	$0 / 1M	$1.50 / 1M
Cache Write (5m)	$0.10 / 1M	$0.10 / 1M	Not applicable	$0.15 / 1M
Cache Write (1h)	$0.10 / 1M	$0.10 / 1M	Not applicable	$0.15 / 1M
Cache Read	$0.10 / 1M	$0.10 / 1M	Not applicable	$0.15 / 1M
Web Search	$0 / 1M	$0 / 1M	$0 / 1M	$0 / 1M
Context
Max context	1.1M	1.1M	N/A	36.9K
Max output	N/A	N/A	N/A	N/A
Capabilities
Vision	Yes	Yes	No	No
Function Calling	Yes	Yes	No	No
JSON Mode	Yes	Yes	No	No
Streaming	Yes	Yes	No	Yes
Catalogue
Provider	OpenAI	OpenAI	Fish Audio	Perceptron
Category	chat	chat	voice	chat
Charge type	Pay As You Go	Pay As You Go	Pay As You Go	Pay As You Go
Released	—	—	2026-07-29	2026-09-25
Description
Summary	GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, optimized for high-volume and latency-sensitive workloads such as chat, classification, and lightweight agentic tasks. It combines low-cost, responsive inference with the GPT-6 family’s improvements in factual reliability and clear, concise communication. At higher reasoning effort, GPT-6 Luna can also handle complex software engineering and computer-use workflows that previously required a Sol-tier model, making it a versatile choice for scalable production applications that need to balance speed, cost, and capability.	GPT-6 Luna Pro uses the same underlying model as GPT-6 Luna, but runs with reasoning.mode set to pro for higher-quality responses on complex tasks. It combines Luna's speed and cost efficiency with deeper reasoning and more reliable multi-step execution, making it well suited for advanced coding, computer use, and agentic workflows where higher solution quality is needed without moving to a larger GPT-6 tier.	Fish Audio S2 Pro text-to-speech. Billed per UTF-8 byte of input text.	Perceptron Mk1.5 chat model that accepts audio input. Audio and text input are billed per token.