GPT-6.1 Terra vs GPT-6 Luna
There is no quality verdict yet: the AIGROW small-business benchmark has not run either model. On price, GPT-6 Luna costs less: $0.10 in and $0.50 out per million tokens, against $1 in and $5 out for GPT-6.1 Terra.
Run GPT-6.1 Terra up to 75% below list price. $25 a month brings $110 of API credit and cancels any time; $25 once buys $100. US dollars, standard rate, shortest context band. Price only: the benchmark has not run both.
- GPT-6.1 Terra
- $5.00
- GPT-6 Luna
- $0.50
- GPT-6.1 Terra, per M tokens
- $1 / $5
- GPT-6 Luna, per M tokens
- $0.10 / $0.50
3,000 tokens in and 400 out each, at list price.
OpenAI's two efficient GPT-6 models, with Luna at a tenth of the Terra price. 1,000 support replies cost $5.00 on GPT-6.1 Terra and $0.50 on GPT-6 Luna, so GPT-6.1 Terra costs 10 times as much. GPT-6.1 Terra was released on 26 Oct 2026, GPT-6 Luna was released on 22 Sep 2026.
What each one costs
The API price per million tokens and the cheapest app plan with each model, from the makers’ own pages. Each name opens that model’s full price page.
- GPT-6.1 Terra
- On the OpenAI API, GPT-6.1 Terra costs $1 per million input tokens and $5 per million output tokens. AIGROW API credit runs GPT-6.1 Terra at $0.25 / $1.25 per million input / output tokens, up to 75% below list price. See API credit
- GPT-6 Luna
- On the OpenAI API, GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens. In ChatGPT, it comes with the free plan, and the cheapest paid plan with it is Go at $8/mo. Plan prices read 14 October 2026.
$25 a month brings $110 of API credit and cancels any time; $25 once buys $100.
Side by side
Each maker’s published rate for its standard tier. Cached input is what a repeated prompt prefix costs once the provider has stored it.
| Fact | GPT-6.1 Terra | GPT-6 Luna |
|---|---|---|
| Maker | OpenAI | OpenAI |
| Tier | Workhorses | Small and fast |
| Input, per M tokens | $1.00 | $0.10 |
| Output, per M tokens | $5.00 | $0.50 |
| Cached input | $0.05 | $0.01 |
| Context window | 1.05M | 1.05M |
| Released | 26 Oct 2026 | 22 Sep 2026 |
| Weights | Closed weights | Closed weights |
What a job costs on each
1,000 runs of each job at the two list prices. The gap moves from job to job because the models price input, output and cached context differently.
| Job | GPT-6.1 Terra | GPT-6 Luna | Cheaper |
|---|---|---|---|
| Support reply3,000 in, 400 out. | $5.00 | $0.50 | GPT-6 Luna, 90% less |
| Document summary25,000 in, 1,000 out. | $30.00 | $3.00 | GPT-6 Luna, 90% less |
| Agent task80,000 in (70,000 cached), 3,000 out. | $28.50 | $3.20 | GPT-6 Luna, 89% less |
The token counts are ours, chosen to look like real work; the prices are the makers’. A model with no published cache price bills the agent task’s repeated context at its full input rate.
The small print
What each base rate leaves out, from the makers’ own pages: surcharges, discounts, promotions and cache pricing.
- GPT-6.1 Terra
- OpenAI pitches it as a fast, efficient model for visual reasoning, computer use and writing. Requests above 272K input tokens bill 2x input and 1.5x output ($2 / $7.50, cached $0.10). Cache write $1.25 (30 min) or $2.50 (12 h). Batch and Flex 50% off, Fast mode 2x. Data residency adds 10%. Context 1,050,000 with max input 922K. OpenAI’s pricing page
- GPT-6 Luna
- Requests above 272K input tokens bill 2x input and 1.5x output ($0.20 / $0.75, cached $0.02). Cache write $0.125. Batch and Flex 50% off, Fast mode 2x. Data residency adds 10%. OpenAI’s pricing page
Other comparisons
Every head to head on the list that involves GPT-6.1 Terra or GPT-6 Luna.
Run GPT-6.1 Terra up to 75% below list price
AIGROW API credit covers GPT-6.1 Terra at published rates never above the list prices here, and $25 buys $100 of credit.
Prices checked 12 November 2026