GPT-6 Luna vs Gemini 3.1 Flash-Lite: API Pricing Compared
Official prices, verified 2026-10-24. Every conclusion on this page is computed from the price data — if the prices change, the verdict changes.
| GPT-6 Luna (OpenAI) | Gemini 3.1 Flash-Lite (Google) | |
|---|---|---|
| Input / 1M | $0.1 | $0.25 |
| Output / 1M | $0.5 | $1.5 |
| Cached input / 1M | $0.01 | Not published |
| Batch tier | Not published | Not published |
| Context window | 1,050,000 | Not published |
| Price verified | 2026-10-24 | 2026-10-24 |
Monthly cost at three workloads
| Workload | GPT-6 Luna | Gemini 3.1 Flash-Lite |
|---|---|---|
| Chat assistant 2,000 input / 500 output tokens per call, 10,000 calls a month | $4.50 | $12.50 |
| Document processing 50,000 input / 2,000 output tokens per call, 1,000 calls a month | $6.00 | $15.50 |
| Agent loop with prompt caching 10,000 fresh input / 100,000 cached input / 2,000 output tokens per call, 500 calls a month | $1.50 | $2.75 |
The verdict, from the data
- GPT-6 Luna has cheaper input: $0.1 vs $0.25 per 1M tokens (60% less).
- GPT-6 Luna has cheaper output: $0.5 vs $1.5 per 1M tokens (67% less).
- At a blended workload of 1M input + 250K output tokens, GPT-6 Luna wins: $0.225 vs $0.625 per call batch.
- Only GPT-6 Luna publishes a cached-input rate ($0.01 per 1M), which matters for prompt-heavy agent workloads.
Run your own numbers in the homepage calculator, or open the dedicated calculators for GPT-6 Luna and Gemini 3.1 Flash-Lite.