API Cost Check
GPT-5 nano vs Gemini 3.5 Flash: cost
For a typical support chatbot, GPT-5 nano is about 28.8× cheaper than Gemini 3.5 Flash ($28.14 vs $810 per month). Price is only one factor: test both on your own prompts before switching.
| GPT-5 nano | Gemini 3.5 Flash | |
|---|---|---|
| Input /1M | $0.05 | $1.50 |
| Output /1M | $0.40 | $9.00 |
| Cached input /1M | $0.005 | $0.15 |
| Batch input /1M | $0.025 | $0.75 |
| Batch output /1M | $0.20 | $4.50 |
| Context window | 400,000 | 1,048,576 |
| Max input | 272,000 | 1,048,576 |
| Max output | 128,000 | 65,536 |
Monthly cost by workload
| Scenario (per month) | GPT-5 nano | Gemini 3.5 Flash |
|---|---|---|
| Customer support chatbot 5,000 req/day · 1,200 in · 400 out · cache 60% | $28.14 | $810 |
| RAG over documents 2,000 req/day · 8,000 in · 600 out · cache 30% | $31.92 | $850 |
| Coding agent 1,500 req/day · 25,000 in · 2,000 out · cache 80% | $51.75 | $1,282 |
| Deep reasoning 800 req/day · 3,000 in · 6,000 out · cache 20% | $60.55 | $1,404 |
| Batch processing 50,000 req/day · 1,500 in · 150 out · batch | $101 | $2,700 |