GPT-6 Luna vs Gemini 2.5 Flash-Lite: API cost comparison
For a typical chatbot (1,500 input + 400 output tokens, 100,000 requests a month), Gemini 2.5 Flash-Lite is 9% cheaper: $31.75 vs $35.00 for GPT-6 Luna. Paste your own prompt below to compare the exact cost of your workload.
0 characters0 words0 tokens (GPT o200k)
| Model | Per month |
|---|---|
| GPT-6 Luna | |
| Gemini 2.5 Flash-Lite |
≈ = estimated token count: only OpenAI publishes its tokenizer. Claude counts use Anthropic’s published ratios; use the count_tokens API for an exact number.
Price per million tokens
USD, standard tier. Prices checked on October 28, 2026.
| GPT-6 Luna | Gemini 2.5 Flash-Lite | |
|---|---|---|
| Input | $0.1 | $0.1 |
| Output | $0.5 | $0.4 |
| Cached input | $0.01 | $0.01 |
| Cache write (5 min) | Not charged separately | Not charged separately |
| Long prompts | Above 272K tokens: $0.2 / $0.75 | Same price at any length |
| Batch API | 50% off | 50% off |
| Provider | OpenAI (GPT) | Google (Gemini) |
Monthly cost for common workloads
| Workload | GPT-6 Luna | Gemini 2.5 Flash-Lite |
|---|---|---|
| Chatbot 1,500 input + 400 output tokens, 100,000 requests a month | $35.00 | $31.75 |
| Document Q&A (RAG) 8,000 input + 500 output tokens, half the input cached, 20,000 requests a month | $13.80 | $13.24 |
| Long-document summary 150,000 input + 2,000 output tokens, 1,000 requests a month | $16.00 | $16.55 |
| Bulk classification (Batch API) 500 input + 20 output tokens, 1 million requests a month, Batch API where available | $30.00 | $30.25 |
Token counts are converted per model: the same text becomes a different number of tokens on each provider (see below). The cheaper option in each row is highlighted.
Frequently asked questions
Is GPT-6 Luna cheaper than Gemini 2.5 Flash-Lite?
Per million tokens, GPT-6 Luna costs $0.1 / $0.5 (input / output) and Gemini 2.5 Flash-Lite costs $0.1 / $0.4. For a typical chatbot workload (1,500 input + 400 output tokens, 100,000 requests a month), Gemini 2.5 Flash-Lite is 9% cheaper: $31.75 vs $35.00 for GPT-6 Luna. Token counts differ between providers, so compare the cost of the same prompt rather than the price per token.
How much do GPT-6 Luna and Gemini 2.5 Flash-Lite cost per million tokens?
GPT-6 Luna: $0.1 / $0.5 for input / output, $0.01 for cached input. Gemini 2.5 Flash-Lite: $0.1 / $0.4, $0.01 for cached input. Prices in US dollars, standard tier, checked on October 28, 2026.
Do GPT-6 Luna and Gemini 2.5 Flash-Lite count tokens the same way?
GPT-6 Luna's tokenizer is not published; we use the o200k count, which is close for newer OpenAI models. Gemini 2.5 Flash-Lite's tokenizer is not published. We estimate about 1.05× the GPT o200k count for the same text.
Do GPT-6 Luna and Gemini 2.5 Flash-Lite have a Batch API discount?
Both do: GPT-6 Luna gets 50% off and Gemini 2.5 Flash-Lite 50% off for requests sent through the Batch API, which may take up to 24 hours.