Gemini 3.5 Flash-Lite vs GPT-5.6 Luna: pricing and benchmarks
GPT-5.6 Luna is 33% cheaper on input tokens ($0.20 vs $0.30 per 1M). GPT-5.6 Luna is 52% cheaper on output tokens ($1.20 vs $2.50 per 1M). On our document Q&A workload (50,000 questions a month), GPT-5.6 Luna costs $116.00 a month versus $195.00 for Gemini 3.5 Flash-Lite, 41% less. GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index vs 145.1 for Gemini 3.5 Flash-Lite.
Prices verified September 14, 2026.
Which should you choose?
GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index vs 145.1 for Gemini 3.5 Flash-Lite.
GPT-5.6 Luna scores 82.1% on FrontierMath (Tiers 1–3) vs 26.0% for Gemini 3.5 Flash-Lite.
GPT-5.6 Luna costs $0.45 per 1M tokens (3:1 input-to-output mix) vs $0.85 for Gemini 3.5 Flash-Lite, 47% less.
GPT-5.6 Luna delivers equal or higher overall capability for 47% less.
Pricing and specs
| Gemini 3.5 Flash-Lite | GPT-5.6 Luna | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-3.5-flash-lite | gpt-5.6-luna |
| Input / 1M tokens | $0.30 | $0.20 |
| Cached input / 1M tokens | $0.03 | $0.02 |
| Output / 1M tokens | $2.50 | $1.20 |
| Long-context rates | — | $0.40 in / $1.80 out on long-context requests |
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 66K tokens | 128K tokens |
| Batch discount | 50% off | 50% off |
Benchmarks
| Gemini 3.5 Flash-Lite | GPT-5.6 Luna | |
|---|---|---|
| Epoch Capabilities Index | 145.1 | 156.3 |
| GPQA Diamond· Science reasoning | 77.8% | 88.8% |
| FrontierMath (Tiers 1–3)· Advanced math | 26.0% | 82.1% |
| SimpleQA Verified· Factual accuracy | — | 41.0% |
| ARC-AGI-2· Abstract reasoning | 10.3% | 59.5% |
| DeepSWE· Coding | — | 67.2% |
| APEX-Agents· Agentic work | — | — |
Source: Epoch AI, best recorded result per model (CC BY 4.0). A dash means no published score. See all benchmarks
Monthly cost for real workloads
| Workload | Gemini 3.5 Flash-Lite | GPT-5.6 Luna | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $145.00 | $78.00 | GPT-5.6 Luna 46% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $195.00 | $116.00 | GPT-5.6 Luna 41% cheaper |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $94.40 | $53.60 | GPT-5.6 Luna 43% cheaper |
Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.
Gemini 3.5 Flash-Lite vs GPT-5.6 Luna cost calculator
- $116.00/mo$0.0023 / request
- Gemini 3.5 Flash-LiteGoogle$195.00/mo$0.0039 / request
Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.
Gemini 3.5 Flash-Lite pricing notes
Google’s lowest-cost Gemini 3.5 model for high-volume work.
- The same input price applies to text, image, video and audio.
- Output price includes thinking tokens.
GPT-5.6 Luna pricing notes
The GPT-5.6 model optimized for cost-sensitive, high-volume workloads.
- Cache writes are billed at $0.25 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
Frequently asked questions
- Is Gemini 3.5 Flash-Lite cheaper than GPT-5.6 Luna?
- GPT-5.6 Luna is 33% cheaper on input tokens ($0.20 vs $0.30 per 1M). GPT-5.6 Luna is 52% cheaper on output tokens ($1.20 vs $2.50 per 1M). On our document Q&A workload (50,000 questions a month), GPT-5.6 Luna costs $116.00 a month versus $195.00 for Gemini 3.5 Flash-Lite, 41% less.
- Which is more capable, Gemini 3.5 Flash-Lite or GPT-5.6 Luna?
- GPT-5.6 Luna scores 156.3 on the Epoch Capabilities Index vs 145.1 for Gemini 3.5 Flash-Lite.
- How much does Gemini 3.5 Flash-Lite cost per 1M tokens?
- Gemini 3.5 Flash-Lite costs $0.30 per 1M input tokens and $2.50 per 1M output tokens, and $0.03 per 1M cached input tokens on Google’s standard tier.
- How much does GPT-5.6 Luna cost per 1M tokens?
- GPT-5.6 Luna costs $0.20 per 1M input tokens and $1.20 per 1M output tokens, and $0.02 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, Gemini 3.5 Flash-Lite or GPT-5.6 Luna?
- GPT-5.6 Luna has the larger context window: 1.05M tokens versus 1.05M for Gemini 3.5 Flash-Lite.