GPT-5.5 vs Gemini 3.1 Pro Preview: API Pricing Comparison
OpenAI GPT-5.5 vs Google Gemini 3.1 Pro Preview — token prices, batch and cache rates, Arena ELO, and cost per request for 8 business use cases. Prices in USD per 1 million tokens. Data snapshot: 2026-08-14.
GPT-5.5 pricing (OpenAI)
- Input: $5.00 per 1M tokens
- Output: $30.00 per 1M tokens
- Batch API (input/output): $2.50 / $15.00
- Prompt-cache read: $0.50
- Context window: 1M
- Arena ELO: 1468 (as of 2026-08-13)
- Full GPT-5.5 pricing page
Gemini 3.1 Pro Preview pricing (Google)
- Input: $2.00 per 1M tokens
- Output: $12.00 per 1M tokens
- Batch API (input/output): $1.00 / $6.00
- Prompt-cache read: $0.20
- Context window: 1M
- Arena ELO: 1480 (as of 2026-08-13)
- Full Gemini 3.1 Pro Preview pricing page
Cost per request by business use case
List price vs optimized (prompt caching on the cached input share, batch API for async workloads — only where the provider publishes those rates).
| Use case | Tokens (in/out) | GPT-5.5 list | GPT-5.5 optimized | Gemini 3.1 Pro Preview list | Gemini 3.1 Pro Preview optimized |
|---|---|---|---|---|---|
| Support Ticket | 1,500 / 500 | $0.022 | $0.018 | $0.0090 | $0.0074 |
| Knowledge Q&A | 2,000 / 800 | $0.034 | $0.028 | $0.014 | $0.011 |
| Meeting Summary | 10,000 / 1,200 | $0.086 | $0.041 | $0.034 | $0.016 |
| Marketing Content | 2,500 / 1,800 | $0.067 | $0.064 | $0.027 | $0.026 |
| Coding Task | 3,000 / 2,000 | $0.075 | $0.068 | $0.030 | $0.027 |
| Invoice Processing | 1,500 / 600 | $0.025 | $0.012 | $0.010 | $0.0047 |
| Call Summary | 2,000 / 700 | $0.031 | $0.015 | $0.012 | $0.0060 |
| Agent Workflow | 6,000 / 3,000 | $0.120 | $0.101 | $0.048 | $0.040 |
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These are list prices — real cost also depends on caching, batching, negotiated discounts, marketplace agreements, and existing contracts. Get a FinOps review from OptimNow or compare all models.