High-volume, cost-sensitive work
Choose Gemini 2.5 Flash-Lite
Gemini 2.5 Flash-Lite costs 13% less on a typical mix of three input tokens for every output token ($0.18 against $0.20 per million tokens).
Gemini 2.5 Flash-Lite vs GPT-6 Luna: price, context and capabilities
Choose Gemini 2.5 Flash-Lite for high-volume, cost-sensitive work and writing and code generation. Choose GPT-6 Luna for reasoning over long documents, the latest release and the most recent knowledge.
In short
- Gemini 2.5 Flash-Lite is 13% cheaper than GPT-6 Luna at the headline price ($0.175 / 1M tokens vs $0.20 / 1M tokens).
- GPT-6 Luna reads more per request: 1.05M tokens against 1.05M.
- GPT-6 Luna is the newer model (Sep 22, 2026, against July 2025).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Writing and code generation
Choose Gemini 2.5 Flash-Lite
Gemini 2.5 Flash-Lite charges $0.40 per million output tokens, against $0.50 for GPT-6 Luna. Output dominates the bill when answers are long.
Reasoning over long documents
Choose GPT-6 Luna
GPT-6 Luna scores 83.3% on Long-context reasoning (AA-LCR), against 32% for Gemini 2.5 Flash-Lite.
Latest release
Choose GPT-6 Luna
GPT-6 Luna is the newer release (Sep 22, 2026, against July 2025 for Gemini 2.5 Flash-Lite).
Most recent knowledge
Choose GPT-6 Luna
GPT-6 Luna was trained on data up to May 2026, against January 2025 for Gemini 2.5 Flash-Lite.
Monthly cost at three volumes
| Volume | Gemini 2.5 Flash-Lite | GPT-6 Luna | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $0.20 | $0.23 | Gemini 2.5 Flash-Lite, $0.03 less |
| Production: 20M input, 5M output tokens | $4.00 | $4.50 | Gemini 2.5 Flash-Lite, $0.50 less |
| Scale: 500M input, 100M output tokens | $90.00 | $100.00 | Gemini 2.5 Flash-Lite, $10.00 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Gemini 2.5 Flash-Lite | GPT-6 Luna | |
|---|---|---|
| Provider | OpenAI | |
| Category | Language models | Language models |
| Status | Legacy | Generally available |
| Headline price | $0.175 / 1M tokens | $0.20 / 1M tokens |
| Input | $0.10 / 1M tokens | $0.10 / 1M tokens |
| Output | $0.40 / 1M tokens | $0.50 / 1M tokens |
| Cached input | $0.01 / 1M tokens | $0.01 / 1M tokens |
| Context window | 1.05M | 1.05M |
| Max output | 66k | 128k |
| Released | July 2025 | Sep 22, 2026 |
| Knowledge cutoff | January 2025 | May 2026 |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | gemini-2.5-flash-lite | gpt-6-luna |
Benchmarks side by side
Leader in bold.
| Benchmark | Gemini 2.5 Flash-Lite | GPT-6 Luna |
|---|---|---|
| Humanity's Last Exam | 3.7% | 38.5% |
| MMMU-Pro (visual reasoning) | 54% | 79.7% |
| Long-context reasoning (AA-LCR) | 32% | 83.3% |
| Terminal-Bench Hard | 2.3% | No data |
| GPQA Diamond | 47.4% | No data |
| IFBench (instruction following) | 31.5% | No data |
| τ²-Bench (agentic tool use) | 19% | No data |
| Intelligence Index | No data | 38.1 |
| SciCode | No data | 54.6% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Gemini 2.5 Flash-Lite or GPT-6 Luna?
Choose Gemini 2.5 Flash-Lite for high-volume, cost-sensitive work and writing and code generation. Choose GPT-6 Luna for reasoning over long documents, the latest release and the most recent knowledge.
Which is cheaper, Gemini 2.5 Flash-Lite or GPT-6 Luna?
Gemini 2.5 Flash-Lite is 13% cheaper than GPT-6 Luna at the headline price ($0.175 / 1M tokens vs $0.20 / 1M tokens).
Which has the larger context window, Gemini 2.5 Flash-Lite or GPT-6 Luna?
GPT-6 Luna reads more per request: 1.05M tokens against 1.05M.
What is the difference between Gemini 2.5 Flash-Lite and GPT-6 Luna?
Gemini 2.5 Flash-Lite is made by Google and GPT-6 Luna by OpenAI. Gemini 2.5 Flash-Lite is 13% cheaper than GPT-6 Luna at the headline price ($0.175 / 1M tokens vs $0.20 / 1M tokens). GPT-6 Luna reads more per request: 1.05M tokens against 1.05M. GPT-6 Luna is the newer model (Sep 22, 2026, against July 2025).
How much do Gemini 2.5 Flash-Lite and GPT-6 Luna cost per month?
At 20 million input and 5 million output tokens a month, Gemini 2.5 Flash-Lite costs $4.00 and GPT-6 Luna costs $4.50, at standard rates.
Which is newer, Gemini 2.5 Flash-Lite or GPT-6 Luna?
GPT-6 Luna was released on Sep 22, 2026 and Gemini 2.5 Flash-Lite on July 2025.