GPT-5.5 vs Gemini 3.5 Flash: cost

For a typical support chatbot, Gemini 3.5 Flash is about 2.7× cheaper than GPT-5.5 ($810 vs $2,214 per month). Price is only one factor: test both on your own prompts before switching.

GPT-5.5 vs Gemini 3.5 Flash: prices and limits
GPT-5.5Gemini 3.5 Flash
Input /1M$5.00$1.50
Output /1M$30.00$9.00
Cached input /1M$0.50$0.15
Batch input /1M$2.50$0.75
Batch output /1M$15.00$4.50
Context window1,050,0001,048,576
Max input1,050,0001,048,576
Max output128,00065,536

Monthly cost by workload

Estimated monthly cost by workload (USD)
Scenario (per month)GPT-5.5Gemini 3.5 Flash
Customer support chatbot
5,000 req/day · 1,200 in · 400 out · cache 60%
$2,214$810
RAG over documents
2,000 req/day · 8,000 in · 600 out · cache 30%
$2,832$850
Coding agent
1,500 req/day · 25,000 in · 2,000 out · cache 80%
$4,275$1,282
Deep reasoning
800 req/day · 3,000 in · 6,000 out · cache 20%
$4,615$1,404
Batch processing
50,000 req/day · 1,500 in · 150 out · batch
$9,000$2,700