GPT-6 Luna Pro API Pricing
OpenAI · context window 1.1M · prices updated 2026-09-29
Where GPT-6 Luna Pro sits on price
At $0.5 per million output tokens, GPT-6 Luna Pro is a mid tier model — 4.4× cheaper than the median output price of $2.20, which puts it cheaper than 79% and pricier than 21% of the models we track. It sits 13th cheapest of the 100 OpenAI models we track. Output costs 5.0× input, the usual spread — trim both, starting with the answer length.
Cached input is 90% cheaper. On an input-heavy workload you need roughly a 28% cache-hit rate to take 25% off the input line — reachable for chatbots and agents that resend the same system prompt and history.
What real workloads cost on GPT-6 Luna Pro
These three workloads are the ones teams actually run on a mid-priced model — a $0.5/1M model is not bought for the same job as one ten times the price.
| Workload | Per request | Per month |
|---|---|---|
| Support chatbot — 500 conversations/day (5K in / 1.4K out) Conversation history re-sent each turn — the classic prompt-caching win. | $0.0012 | $18.00 |
| Document pipeline — 10K docs/day (3K in / 500 out) Batch-friendly: no user waiting, so a ~50% batch discount usually applies. | $0.0006 | $165 |
| Long-context analysis — 200 runs/day (250K in / 4K out) Only possible on large-context models; input cost is nearly the whole bill. | $0.027 | $162 |
Model your exact traffic in the API cost calculator — it preloads GPT-6 Luna Pro with caching and batch options.
GPT-6 Luna Pro price history
GPT-6 Luna Pro's price has not moved since we began tracking it on Sep 23, 2026 — 6 days of stability in a market where 88 of the 353 models we track have repriced over the same period, including 12 of OpenAI's own 100 models.
Change-points from our daily price snapshots (tracking since Sep 23, 2026; intraday moves between snapshots are not captured).
GPT-6 Luna Pro vs Qwen3 30B A3B
The closest-priced alternative from another vendor is Qwen3 30B A3B (Alibaba (Qwen)) — priced within a rounding error on output, with $0.02 more per million input tokens. When two models land this close on price, the decision is quality on your own workload, not the price sheet: run 50 real requests through both and compare.
See Qwen3 30B A3B pricing →Cheaper alternatives
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Frequently asked questions
› How much does the GPT-6 Luna Pro API cost?
GPT-6 Luna Pro costs $0.1 per million input tokens and $0.5 per million output tokens, with cached input at $0.01 per million (90% cheaper). That works out to roughly 2,000,000 output tokens per dollar.
› What does the support chatbot workload cost on GPT-6 Luna Pro?
Support chatbot — 500 conversations/day (5K in / 1.4K out) costs about $0.0012 per request and $18.00 per month on GPT-6 Luna Pro. Conversation history re-sent each turn — the classic prompt-caching win.
› What does it cost to fill GPT-6 Luna Pro's 1.1M context window?
Sending 1.1M of input in a single request costs $0.105 at $0.1 per million tokens — before any output. With prompt caching that same fill drops to about $0.0105 on repeat requests. This is why large context windows are cheap to advertise and expensive to actually use.
› Is GPT-6 Luna Pro worth the price?
GPT-6 Luna Pro sits in the middle of the market (13 of 100 by price within OpenAI). The honest test is a routing experiment: send the same 200 real requests to this model and to a tier below, and compare failure rate against the price gap — most teams find a majority of traffic never needed the pricier model.