Simulating realistic Customer support chatbot parameters (3,500 in / 350 out with 70% cache reuse). Gemini 3.6 Flash delivers a 33% cost reduction over GPT-5.6 Terra.
Quick answer
For Customer support chatbot, Gemini 3.6 Flash is the lower-cost option at $0.004568 per request versus $0.00679 for GPT-5.6 Terra, a modeled saving of 33%.
Method & trust
The comparison uses 3,500 input tokens, 350 output tokens, and 70% cache reuse for the selected workload. Pricing is applied per model, then scaled to monthly request volumes.
| Traffic Volume Tier | GPT-5.6 Terra Monthly | Gemini 3.6 Flash Monthly | Monthly Savings by picking Gemini 3.6 Flash |
|---|---|---|---|
| 1,000 reqs/mo (Dev/Testing) | $6.79 | $4.568 | Save $2.222 / mo |
| 10,000 reqs/mo (Small App) | $67.90 | $45.675 | Save $22.225 / mo |
| 100,000 reqs/mo (Growth Production) | $679.00 | $456.75 | Save $222.25 / mo |
| 1,000,000 reqs/mo (Scale SaaS) | $6,790.00 | $4,567.50 | Save $2,222.50 / mo |
Gemini 3.6 Flash is 33% cheaper for Customer support chatbot workloads. At standard Customer support chatbot parameter ratios (3,500 input tokens, 350 output tokens, 70% cache hit), Gemini 3.6 Flash costs $0.004568 per request compared to $0.00679 on GPT-5.6 Terra.
GPT-5.6 Terra offers a context window of 1,050,000 tokens (max output: 128,000), while Gemini 3.6 Flash offers 1,000,000 tokens (max output: 64,000).
At 100,000 requests per month, using Gemini 3.6 Flash saves $222.25 every month (or $2,667.00 annually) compared to GPT-5.6 Terra.
Cache the system prompt and static documentation chunks — cached input is often 4–10× cheaper. Route simple FAQ turns to a nano-tier model and escalate only complex tickets. Cap max_output per reply; support answers rarely need more than a few hundred tokens.