GPT-5.6 Luna API Pricing
GPT-5.6 Luna is OpenAI's fast, low-cost GPT-5.6 tier: $0.20/M input, $1.20/M output, and $0.02/M cached input. OpenAI cut GPT-5.6 prices on July 30, 2026, about three weeks after the family shipped: Luna fell 80%, Terra 20%, and Sol was left unchanged. Luna took the deepest cut in the family, and it lands at a rate that puts a US frontier-family model into the price band Chinese budget tiers had to themselves. Pulled directly from developers.openai.com daily.
Run the numbers.
Live calculator pre-loaded with current GPT-5.6 Luna standard short-context rates. Tweak spend, output mix, or cache hit rate; share the URL to share the calculation.
Real-world presets.
Support agent ticket triage
Bulk routing decision
SEO draft outline
Daily workflow turn
Paste text. See tokens. See cost.
Counted with the o200k_base BPE encoding — the same tokenizer the API uses — entirely in your browser. The encoder loads on your first keystroke (~1 MB, one time); your text never leaves this page.
| Model | Input /M | Output /M | Effective blended | Context | Best for |
|---|---|---|---|---|---|
| GPT-5.6 Sol | $4.00 cache $0.40 | $20.00 | $2.73 same blend | 1.05M | Highest-accuracy GPT-5.6 preview |
| GPT-5.6 Terra | $2.00 cache $0.20 | $12.00 | $1.52 same blend | 1.05M | Balanced GPT-5.6 preview agents |
| GPT-5.6 Luna Current | $0.20 cache $0.02 | $1.20 | $0.152 agentic 92/8 | 1.05M | Cheapest GPT-5.6 preview routing |
| GPT-5.5 | $5.00 cache $0.50 | $30.00 | $3.61 same blend | 1M | Current broadly available OpenAI flagship |
| GPT-5.4 | $2.50 cache $0.25 | $15.00 | $1.80 same blend | 1.05M | Broadly available balanced OpenAI tier |
| GPT-5.4 mini | $0.75 cache $0.075 | $4.50 | $0.541 same blend | 400K | Lower-cost OpenAI subagents |
| Claude Opus 4.8 | $5.00 cache $0.50 | $25.00 | $3.41 same blend | 1M | Anthropic Opus frontier alternative |
| Gemini 3.5 Flash | $1.50 cache $0.15 | $9.00 | $1.08 same blend | 1M | Google multimodal context alternative |
Compare siblings
Frequently asked.
Practical GPT-5.6 Luna pricing questions, with OpenAI's published rates separated from workload assumptions.
Q · 01 How much does GPT-5.6 Luna cost? +
Q · 02 Is GPT-5.6 Luna generally available? +
Q · 03 What is the context window? +
1.05M-token context window and 128K max output for GPT-5.6 Luna, with a stated knowledge cutoff of February 16, 2026.Q · 04 How much cheaper are Batch and Flex? +
Q · 05 When does long-context pricing apply? +
272K input tokens, GPT-5.6 Luna uses the long-context tier: $0.40/M input, $0.04/M cached input, and $1.80/M output — double the standard input rate and 1.5x the standard output rate. The calculator on this page uses the standard short-context tier.Q · 06 Which GPT-5.6 tier should I choose? +
$3.81/M, Terra near $1.52/M, and Luna near $0.15/M — after the July 30 cut, Luna is 25x cheaper than Sol rather than the 5x it was at launch, which changes the routing maths more than the headline discount suggests.