OpenAIProprietaryReleased Jul 9, 2026GPT-5.6 Luna pricing, benchmarks and cost analysis
Epoch Capabilities Index (ECI)range 154.2 to 159.3
Median output tokens per second
In $0.200Out $1.20 per 1MCache discount 90%
Context window, tokens
Ranks are among the 101 models we track (intelligence = Epoch Capabilities Index by Epoch AI, CC BY 4.0; intelligence and speed: among those with data; cost: #1 is cheapest). Monthly cost uses the default workload of 2,000 input and 500 output tokens, 10,000 requests a day, 40% cached.
Comparison summary
GPT-5.6 Luna costs $257 a month for the default workload of 2,000 input and 500 output tokens, 10,000 requests a day with 40% cached input. That is 71% below the median model ($873). It ranks #21 of 101 on cost, where #1 is the cheapest.
It scores 156.5 on the Epoch Capabilities Index (#26 of 66). Among the 18 other models within 2 points, 1 costs less, and it costs 85% less than their median ($1,710). The cheapest stable-priced model that scores at least as high is Claude Haiku 5.5 (159.3) at $113 a month, 56% less.
It generates 129 tokens per second, 54% faster than the median model (84), #7 of 28. Cached input is 90% cheaper than fresh input, in line with the 90% median. It is a proprietary model served by OpenAI. The batch API cuts the default workload to $128 a month.
Technical specifications
- Context window
- 1M tokens
- Input price
- $0.200 / 1M
- Cached input price
- $0.020 / 1M
- Output price
- $1.20 / 1M
- Cache discount
- 90%
- Batch API
- Available
- Batch input / cached / output
- $0.100 / $0.010 / $0.600
- Open weights
- No
- Release date
- Jul 9, 2026
- Time to first token
- 75.37 s
- Price volatility
- Stable
Benchmarks
Best score for this model on each leaderboard, ranked against the other models listed there.
Your monthly bill
Standard
$257 / month- Input
- $72.00
- Cached input
- $4.80
- Output
- $180.00
Batch
$128 / month- Input
- $36.00
- Cached input
- $2.40
- Output
- $90.00
On the default workload the batch API costs $128 a month against $257 standard.
Price history
No price changes since we started tracking on Jul 13, 2026.
Cheaper alternatives
Models with stable pricing and a Epoch Capabilities Index within 2 points of GPT-5.6 Luna (or higher) that cost less for the default workload.
