GPT-6 Luna vs Gemini 3.1 Pro Preview: cost

For a typical support chatbot, GPT-6 Luna is about 28.0× cheaper than Gemini 3.1 Pro Preview ($38.51 vs $1,080 per month). Price is only one factor: test both on your own prompts before switching.

GPT-6 Luna vs Gemini 3.1 Pro Preview: prices and limits
GPT-6 LunaGemini 3.1 Pro Preview
Input /1M$0.10$2.00
Output /1M$0.50$12.00
Cached input /1M$0.01$0.20
Batch input /1M$0.05$1.00
Batch output /1M$0.25$6.00
Context window1,050,0001,048,576
Max input922,0001,048,576
Max output128,00065,536

Monthly cost by workload

Estimated monthly cost by workload (USD)
Scenario (per month)GPT-6 LunaGemini 3.1 Pro Preview
Customer support chatbot
5,000 req/day · 1,200 in · 400 out · cache 60%
$38.51$1,080
RAG over documents
2,000 req/day · 8,000 in · 600 out · cache 30%
$53.64$1,133
Coding agent
1,500 req/day · 25,000 in · 2,000 out · cache 80%
$79.31$1,710
Deep reasoning
800 req/day · 3,000 in · 6,000 out · cache 20%
$77.90$1,872
Batch processing
50,000 req/day · 1,500 in · 150 out · batch
$169$3,600