OpenAI

GPT-5.6 Luna

The fastest, most affordable GPT-5.6 tier for high-volume drafting, summarization, and routine automation where latency and cost dominate.

ActiveReleased July 9, 2026Knowledge cutoff February 16, 2026Available from 2 providers
Tool callingCan invoke external tools and APIs (function calling) mid-response.Structured outputCan return JSON or schema-constrained responses instead of free text.ReasoningUses extended thinking / chain-of-thought for harder multi-step problems.Effort controlLets you dial thinking depth (low / medium / high) to trade cost for quality.Fine-tuningSupports training a custom variant on your own data (vendor fine-tune API or self-hosted open weights).

Source: OpenAI models, OpenAI pricing, Prompt caching (1,024 minimum, 30m TTL)

Price per 1M tokens
$0.2 in / $1.2 out
Context window1,050,000
Max output128,000
Cache read$0.02 / M
Min cache prefix1,024 tokens
Cache lifetime30 min
Batch discount-50%
ModalitiesText, Image → Text
Priced across2 providers

Pricing

Every billing leg from the live catalog, in USD per 1M tokens.

Billing legStandardLong contextBatch
Input$0.2 / M$0.4 / M$0.1 / M
Output$1.2 / M$1.8 / M$0.6 / M
Cache read$0.02 / M$0.04 / M$0.01 / M
Cache write$0.25 / M$0.5 / M$0.125 / M

Long-context rates apply above 272,000 input tokens.

Cost calculator

Billing-grade math over the rate card above, including the thinking tokens most estimates miss.

Hidden reasoning tokens bill as output. 1.0x = thinking off. Medium-effort reasoning typically lands near 3x; heavy reasoning runs 6x to 8x. Set it to match your workload.

Estimated monthly cost
$112
at current list prices
Fresh input$40.00
Cached input$0.00
Output incl. thinking$72.00
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Compare providers

The same model, priced across every platform that serves it. Lowest combined in/out rate is flagged.

PlatformInput / MOutput / MCache read / MBatchAccess
OpenAILowest
$0.2$1.2$0.02✓First-party API
Cursor
$0.2$1.2$0.02—Direct

Price history

Has this model gotten cheaper or more expensive?

EffectiveInput / OutputStatus
July 10, 2026 – July 30, 2026$1 / $6past
July 30, 2026$0.2 / $1.2current

More from OpenAI

Other models from the same provider.

GPT-5.6 Sol
openai/gpt-5.6-sol
$5 / $30 in / out per 1M
GPT-5.6 Terra
openai/gpt-5.6-terra
$2 / $12 in / out per 1M
GPT-5.5
openai/gpt-5.5
$5 / $30 in / out per 1M
GPT-5.5 Pro
openai/gpt-5.5-pro
$30 / $180 in / out per 1M
GPT-5.4
openai/gpt-5.4
$2.5 / $15 in / out per 1M
GPT-5.4 mini
openai/gpt-5.4-mini
$0.75 / $4.5 in / out per 1M

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Rates are generated from SuperPenguin's live pricing catalog.