Is GPT-6 Astra or GPT-5.6 Luna cheaper?

GPT-5.6 Luna is cheaper for a typical request of 1,000 input and 500 output tokens: $0.0008 versus $0.035 for GPT-6 Astra, about 98% less.

What are the per-token prices of GPT-6 Astra and GPT-5.6 Luna?

GPT-6 Astra costs $10.00 input and $50.00 output per million tokens. GPT-5.6 Luna costs $0.20 input and $1.20 output per million tokens.

Which has the larger context window, GPT-6 Astra or GPT-5.6 Luna?

Both accept 1.05M tokens of context.

OpenAI vs OpenAI

GPT-6 Astra vs GPT-5.6 Luna: pricing comparison

GPT-5.6 Luna costs 43.8× less than GPT-6 Astra for a typical 1,000-input, 500-output request. Here is how the two compare on price, context and discounts.

Prices last updated: September 25, 2026

	GPT-6 Astra	GPT-5.6 Luna
Provider	OpenAI	OpenAI
Input per 1M tokens	$10.00	$0.20
Output per 1M tokens	$50.00	$1.20
Context window	1.05M	1.05M
Batch discount	50% off	50% off
Typical request (1,000 in / 500 out)	$0.035	$0.0008
Monthly at 1,000 requests/day	$1,050.00	$24.00

GPT-6 Astra: OpenAI's flagship model, released September 2026.

GPT-5.6 Luna: Inputs above 272K tokens are billed at a higher long-context rate ($0.40 / $1.80).

Compare with your own numbers

Input tokens

Output tokens

Requests / day

GPT-6 Astra per request: $0.035
Per month: $1,050.00

GPT-5.6 Luna per request: $0.0008
Per month: $24.00

Cost by task

Cost per 1,000 requests at standard prices.
Task	Tokens (in / out)	GPT-6 Astra	GPT-5.6 Luna
Short chat reply	500 / 300	$20.00	$0.46
RAG answer	6,000 / 600	$90.00	$1.92
Summarize a long document	12,000 / 1,000	$170.00	$3.60
Output-heavy generation	1,000 / 4,000	$210.00	$5.00

Output tokens usually dominate the bill — see input vs output token cost.

Frequently asked questions

Is GPT-6 Astra or GPT-5.6 Luna cheaper?: GPT-5.6 Luna is cheaper for a typical request of 1,000 input and 500 output tokens: $0.0008 versus $0.035 for GPT-6 Astra, about 98% less.
What are the per-token prices of GPT-6 Astra and GPT-5.6 Luna?: GPT-6 Astra costs $10.00 input and $50.00 output per million tokens. GPT-5.6 Luna costs $0.20 input and $1.20 output per million tokens.
Which has the larger context window, GPT-6 Astra or GPT-5.6 Luna?: Both accept 1.05M tokens of context.

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