GPT-6 Luna API pricing
Official OpenAI list price, last checked Oct 29, 2026. Updated Oct 29, 2026.
GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, cached input at $0.01, and a 1M-token context window, per OpenAI's official pricing page (checked Oct 29, 2026). It's one of the cheapest models we track: number 7 of 77 by blended price ($0.20 per 1M tokens at a 3 to 1 input to output mix). On LMArena's Code Arena it ranks #27 of 50 models we price (relative score 15 out of 100). It's one of our LMArena value picks for cheap bulk and agents.
GPT-6 Luna price per million tokens
| GPT-6 Luna price per million tokens | USD |
|---|---|
| Input | $0.10 |
| Cached input | $0.01 |
| Output | $0.50 |
| Blended, 3 parts input to 1 part output | $0.20 |
| Context window | 1M tokens |
Official note from OpenAI: Prompts up to 272K.
What GPT-6 Luna costs for real work
List-price estimates for a month, no discounts. Our math, not a quote: change the token counts in the plan vs API calculator.
| Workload | Tokens a month | GPT-6 Luna | Claude Haiku 5.5 |
|---|---|---|---|
| Light: a side project or personal assistant | 2M in, 0.5M out | $0.45 | $0.45 |
| Medium: a small team or one product feature | 20M in, 5M out | $4.50 | $4.50 |
| Heavy: a production app | 200M in, 50M out | $45.00 | $45.00 |
| Medium with 80% of input cached | 20M in (16M cached), 5M out | $3.06 | $3.06 |
How GPT-6 Luna ranks on LMArena
Relative score: 100 is the top model we price on that board. Rank is among the models in our price table, not the full leaderboard.
| Board | Rank | Score /100 |
|---|---|---|
| Coding (Code Arena) | #27 of 50 | 15 |
| Chat (Text Arena) | #40 of 51 | 0 |
| Creative writing (Text Arena creative writing) | #35 of 51 | 0 |
| Roleplay and characters (Text Arena multi-turn) | #40 of 51 | 0 |
| Reasoning and math (Text Arena math) | #36 of 51 | 0 |
| Vision (Vision Arena) | #29 of 33 | 0 |
| Cheap bulk and agents (Agent Arena) | #15 of 34 | 51 |
Closest rivals to GPT-6 Luna
The models nearest in price, other makers first. Ranks are on Code Arena, where we have them.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| Claude Haiku 5.5 | $0.10 / $0.50 | $0.20 | Claude Haiku 5.5 wins: same price, higher score. Compare |
| ERNIE 4.5 Turbo | $0.11 / $0.45 | $0.195 | Same price, no score to separate them. Compare |
| Qwen3.5 Flash | $0.10 / $0.40 | $0.175 | Qwen3.5 Flash for price, GPT-6 Luna for quality. Compare |
| Seed 2.0 Mini | $0.10 / $0.40 | $0.175 | Seed 2.0 Mini wins on price. Compare |
Cheaper alternatives to GPT-6 Luna
Nothing in our table is at least 40% cheaper blended. See the cheapest LLM API ranking for the low end.
More from OpenAI
- GPT-6.1 Terra$1 in, $5 out per 1M
- GPT-6.1 Sol$2 in, $10 out per 1M
- GPT-6 Sol$2 in, $10 out per 1M
- GPT-5.6 Terra$2 in, $12 out per 1M
- GPT-5.6 Sol$4 in, $20 out per 1M
FAQ
How much does the GPT-6 Luna API cost per million tokens?
$0.10 per 1M input tokens and $0.50 per 1M output tokens, plus $0.01 per 1M for cached input, as of Oct 29, 2026. A typical 3 to 1 input to output mix works out to $0.20 per 1M tokens.
Does GPT-6 Luna charge more for long prompts?
OpenAI doesn't list a long-prompt surcharge for GPT-6 Luna. Its pricing note says: Prompts up to 272K.
Is GPT-6 Luna cheaper than Claude Haiku 5.5?
About the same. A medium month (20M input and 5M output tokens) costs $4.50 on GPT-6 Luna and $4.50 on Claude Haiku 5.5 at list price. On Code Arena, GPT-6 Luna ranks #27 and Claude Haiku 5.5 #24.
How does GPT-6 Luna rank on LMArena?
On Code Arena it is #27 of 50 models we price, with a relative score of 15 out of 100. It ranks on 7 of 8 boards we track.
What is a cheaper alternative to GPT-6 Luna?
Few models undercut it by much. The next closest in price is Claude Haiku 5.5 at $0.20 blended.
Where does this GPT-6 Luna price come from?
From OpenAI's official pricing page, which we check every day. This page was last checked Oct 29, 2026.