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GPT-5.6 Luna API Pricing & Cost Calculator

By TechCompare · Updated · How we check

Route classification and formatting requests to Luna, which lists at $0.20/$1.20 per million, below Terra on both rows. Pair it with the 90% cache discount to cut per-token cost on repetitive workloads.

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Cost Comparison

Based on 30,000 input tokens (50% cached), 3,000 output tokens, and 1,000 requests.Prices come live from OpenRouter at each maker's own price where it's listed. Temporary deals are left out.

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Same 30,000 in / 3,000 out (50% cached) scenario, pre-loaded. Adjust tokens, caching, or swap models.
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GPT-5.6 Luna is the cheapest tier of OpenAI's 5.6 lineup, designed for high-volume classification, extraction, and routing tasks. It sits an order of magnitude below Sol and Terra on price.

OpenAI: GPT-5.6 Luna

OpenAI's own price

Input
$0.20
Output
$1.20
Cached
$0.02

per 1M tokens

Batch availableFlex available

Price checked 2026-11-12

How this is calculated

GPT-5.6 Luna is priced at $0.20 per million input tokens and $1.20 per million output tokens at OpenAI's published list price, with a prompt caching discount of 90% ($0.02 per million cached reads). That's 10x cheaper than GPT-5.6 Terra ($2/$12) on input and 10x cheaper on output, putting it in the high-volume utility tier alongside MiniMax-M3.

Verdict

Use Luna for one-shot classification and formatting and send anything more complex up to Terra. It's the cheapest tier of the GPT-5.6 lineup at $0.20/M input and $1.20/M output. The 90% cache discount takes cached input to $0.02/M, which cuts the input cost of a stable system prompt reused across millions of daily classification or formatting requests.

A representative 30K input + 1K output utility call lands at roughly $0.0072 before discounts and $0.00234 when 27,000 of the 30K input tokens are cache reads, including the unchanged $0.0012 output charge. Terra at $2/$12 costs 10x Luna on input.

More API Standalones scenarios

GPT-5.6 Luna vs MiniMax-M3
Two utility tier models for high volume work. Compare token rates and caching.
View details
Claude Fable 5.1 vs GPT-6 Astra
Compare sticker prices on both tiers and see how much the cache discount changes the bill.
View details
Claude Haiku 5.5 vs GPT-6 Luna
Small fast models at volume, with cache reads, batch jobs, and Haiku's long prompt tier in the math.
View details

Related guides

Token cost calculator
How per-token counts turn into API costs.
View guide
Prompt optimization
Cutting tokens is the cheapest way to cut cost.
View guide

Frequently asked questions

Is GPT-5.6 Luna too cheap to be good?
No, not for the work it's meant for. Luna's intelligence tier is intentionally lower than Terra's and Sol's, so use it for classification, extraction, summarization, and other deterministic work where small models do well. For complex reasoning, move up to Terra or Sol.
How much does GPT-5.6 Luna cost per million output tokens?
GPT-5.6 Luna's standard output rate is $1.20 per million tokens, with cached input listed at $0.02 per million. Batch jobs run at $0.10 input and $0.60 output per million, so check provider availability before estimating them.

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