LOW-COST FRONTIERPRICE CUT -80%GPT-5.6 FAMILY1.05M CONTEXTTEXT + VISIONPROMPT CACHING
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. Checked by hand against developers.openai.com.
Input - per 1M tokens
$0.20/M
Short context up to 272K input standard
Output - per 1M tokens
$1.20/M
Long context output is $1.80/M standard
Cached input - 90% off
$0.02/M
Prompt cache read price -90%
Effective - agentic blend
$0.152/M
92/8 split - 82% cache
§ 01 / TERMINAL
GPT-5.6 Luna API cost calculator.
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.
$ /mo
Workload split
Prompt cache hit rate
Tokens you can process
—
Words equivalent (English)
—
Effective rate
—
§ 02 / SCENARIOS
GPT-5.6 Luna cost on real workloads.
RAG - SUPPORT
Support agent ticket triage
$0.00254/ticket
CLASSIFICATION
Bulk routing decision
$0.00048/decision
CONTENT
SEO draft outline
$0.00193/outline
ASSISTANT
Daily workflow turn
$0.00072/turn
Exact · o200k_base Auto-counts as you type
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.
Characters 611
Words 95
Tokens (exact) 158 tokens
Cost as input · uncached $0.00003 USD
Cost as output · uncached $0.00019 USD
Cost as cached input $0.000003 USD
| Model | Input /M | Output /M | Effective blended | Context | Best for |
|---|---|---|---|---|---|
| GPT-5.6 Sol | $4.00 cache $0.40 | $20.00 | $2.73 +18× · promo | 1.05M | Highest-accuracy GPT-5.6 preview |
| GPT-5.6 Terra | $2.00 cache $0.20 | $12.00 | $1.52 +10× | 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 +24× | 1M | Current broadly available OpenAI flagship |
| GPT-5.4 | $2.50 cache $0.25 | $15.00 | $1.80 +12× | 1.05M | Broadly available balanced OpenAI tier |
| GPT-5.4 mini | $0.75 cache $0.075 | $4.50 | $0.541 +3.5× | 400K | Lower-cost OpenAI subagents |
| Claude Opus 4.8 | $5.00 cache $0.50 | $25.00 | $3.41 +22× | 1M | Anthropic Opus frontier alternative |
| Gemini 3.6 Flash | $0.75 cache $0.075 | $3.75 | $0.481 +3.2× · promo | 1M | Google multimodal context alternative |
Compare siblings
GPT-5.6 Luna has published scores on 9 benchmarks we track; its best placing is #30 of 99 on ARC-AGI-1. 4 of these scores come from an independent leaderboard; the rest are the lab's own reports.
| Benchmark | Score | Rank | Leader | Source |
|---|---|---|---|---|
| ARC-AGI-1 Reasoning | 90.7% ARC Prize verified, best result | #30 of 99 | 6 tied · 98.5% | Official leaderboard ARC Prize Foundation |
| ARC-AGI-2 Reasoning | 59.6% ARC Prize verified, best result | #38 of 105 | GPT-6 Astra · 95% | Official leaderboard ARC Prize Foundation |
| DeepSWE Coding | 62.2% max effort | #19 of 27 | Gemini 4 Argon · 77.9% | Vendor-reported OpenAI |
| ARC-AGI-3 Reasoning · Standard harness | 0.2% ARC Prize verified, best result | #18 of 24 | GPT-6 Astra · 62.7% | Official leaderboard ARC Prize Foundation |
| Terminal-Bench 4.0 Agents and computer use | 17.3% max effort, Codex harness, 330 trials, ±2.9 pts (95% CI) | #26 of 34 | Kimi K3.1 Pro · 65.7% | Official leaderboard Terminal-Bench (Stanford, Laude Institute) |
| OSWorld 2 Agents and computer use · 2.0, offline subset, partial score | 52.7% max effort | #6 of 7 | GPT-6 Astra · 73.5% | Vendor-reported OpenAI |
| FrontierCode Coding · v1.1 Main (100 hardest tasks) | 39.8% max effort | #12 of 13 | Claude Opus 5.5 · 54.4% | Vendor-reported OpenAI |
| AutomationBench Agents and computer use · Main set (as reported) | 17% max effort, v1.0.6 | #21 of 22 | MiniMax M3.1 Flash · 62.8% | Vendor-reported OpenAI |
| Agents' Last Exam Agents and computer use · ALE v1 | 50.4% max effort | #5 of 5 | GPT-6 Astra · 59.3% | Vendor-reported OpenAI |
GPT-5.6 Luna API pricing FAQ.
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? +
OpenAI lists GPT-5.6 Luna at $0.20/M input tokens, $0.02/M cached input tokens, $0.25/M cache writes and $1.20/M output tokens in the standard short-context tier — down 80% from the $1/$0.10/$6 launch rates. Verified on OpenAI's pricing docs 2026-08-02.
Q · 02 Is GPT-5.6 Luna generally available? +
Yes. OpenAI made the GPT-5.6 series (Sol, Terra, Luna) generally available on July 9, 2026 across ChatGPT, Codex, and the API, after an initial limited preview that opened June 26, 2026.
Q · 03 What is the context window? +
OpenAI's model docs list a
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? +
OpenAI lists Batch and Flex for GPT-5.6 Luna at half the standard short-context rate: $0.10/M input, $0.01/M cached input, and $0.60/M output. Priority is $0.40/M input, $0.04/M cached input, and $2.40/M output. All four tiers moved with the July 30 cut.
Q · 05 When does long-context pricing apply? +
For requests above
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? +
Use Sol for the hardest tasks, Terra for balanced agent workloads, and Luna for lower-cost routing or high-volume production. In the shared 92/8 agentic blend with 82% cache hits, Sol lands near
$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.