GPT-6 Luna vs GPT-5 nano: cost

For a typical support chatbot, GPT-5 nano is about 1.4× cheaper than GPT-6 Luna ($28.14 vs $38.51 per month). Price is only one factor: test both on your own prompts before switching.

GPT-6 Luna vs GPT-5 nano: prices and limits
GPT-6 LunaGPT-5 nano
Input /1M$0.10$0.05
Output /1M$0.50$0.40
Cached input /1M$0.01$0.005
Batch input /1M$0.05$0.025
Batch output /1M$0.25$0.20
Context window1,050,000400,000
Max input922,000272,000
Max output128,000128,000

Monthly cost by workload

Estimated monthly cost by workload (USD)
Scenario (per month)GPT-6 LunaGPT-5 nano
Customer support chatbot
5,000 req/day · 1,200 in · 400 out · cache 60%
$38.51$28.14
RAG over documents
2,000 req/day · 8,000 in · 600 out · cache 30%
$53.64$31.92
Coding agent
1,500 req/day · 25,000 in · 2,000 out · cache 80%
$79.31$51.75
Deep reasoning
800 req/day · 3,000 in · 6,000 out · cache 20%
$77.90$60.55
Batch processing
50,000 req/day · 1,500 in · 150 out · batch
$169$101