Gemini 3.8 Flash vs GPT-5.6 Luna Pro
Pick up to 3 models · pricing, context and capabilities · simulate your product cost
Data updated on September 30, 2026· 217 models
Gemini 3.8 Flash is Google's most intelligent Flash model with significant gains from 3.7 Flash across software engineering, agentic tasks, and multi-step reasoning.
- Reasoning estimated
- Speed estimated
- Input
- Output
- Context
- 1 M tokens
- Max output
- 66 K
- Input, $ per 1M tokens
- $0.750
- Output, $ per 1M tokens
- $3.75
- Cache read, $ per 1M
- $0.075
- Batch (input / output)
- $0.375 / $1.88
- Tool calling
- Yes
- Released
- ▲09/02/2026
- Knowledge cutoff
- —
- API id
- google/gemini-3.8-flash
GPT-5.6 Luna Pro is the same underlying model as GPT-5.6 Luna, served with reasoning.mode set to pro for higher-quality responses on complex tasks.
- Reasoning estimated
- ▲
- Speed estimated
- Input
- Output
- Context
- ▲1.1 M tokens
- Max output
- ▲128 K
- Input, $ per 1M tokens
- ▲$0.200
- Output, $ per 1M tokens
- ▲$1.20
- Cache read, $ per 1M
- $0.020
- Batch (input / output)
- $0.100 / $0.600
- Tool calling
- Yes
- Released
- 07/09/2026
- Knowledge cutoff
- 2026-02-16
- API id
- openai/gpt-5.6-luna-pro
Which is the better API choice: Gemini 3.8 Flash vs GPT-5.6 Luna Pro?
- GPT-5.6 Luna Pro: cheapest input (73% less than Gemini 3.8 Flash)
- GPT-5.6 Luna Pro: cheapest output
- GPT-5.6 Luna Pro: largest context (1.1 M)
- Gemini 3.8 Flash: the newest (09/02/2026)
- GPT-5.6 Luna Pro: most reasoning (estimated)
GPT-5.6 Luna Pro costs 73% less on input and 68% less on output than Gemini 3.8 Flash ($0.200 / $1.20 versus $0.750 / $3.75 per million tokens). GPT-5.6 Luna Pro accepts more context (1.1 M). On capabilities, only Gemini 3.8 Flash accepts audio. Gemini 3.8 Flash and GPT-5.6 Luna Pro offer a batch tier at half price for jobs that do not need an immediate answer.
What would your product cost?
Estimate the monthly cost with your app's real volume. List prices, no cache or batch discounts.
With GPT-5.6 Luna Pro you save $18.45 a month versus Gemini 3.8 Flash (70% less).
The 6 cheapest for this scenario (chat, last 12 months)
- 1Lyria 3 Pro Preview Google$0.00
- 2Lyria 3 Clip Preview Google$0.00
- 3Qwen3.7 Flash Qwen$0.97
- 4DeepSeek V4 Flash 0731 DeepSeek$1.55
- 5Ministral 3 3B 2512 Mistral$1.90
- 6Qwen3.5-Flash Qwen$2.02
Paste your prompt: tokens and cost per model
Rough estimate (about 4 characters per token). Nothing is sent to any server.
Cost of sending it 1,000 times (input only)
- 1GPT-5.6 Luna Pro OpenAI$0.015
- 2Gemini 3.8 Flash Google$0.057
- 3Claude Sonnet 5.5 Anthropic$0.152
- 4Claude Sonnet 5 Anthropic$0.152
- 5Claude Opus 5.5 Anthropic$0.304
- 6Claude Opus 5 Anthropic$0.380
- 7Claude Fable 5.1 Anthropic$0.760
- 8Claude Fable 5 Anthropic$0.760
Popular comparisons
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- GPT-6.1 Sol vs Gemini 3.8 Flash
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- GPT-6.1 Sol vs Grok 4.7
- Gemini 3.8 Flash vs DeepSeek V4.1 Flash
- Gemini 3.8 Flash vs Grok 4.7
- DeepSeek V4.1 Flash vs Grok 4.7
Frequently asked questions
Which is the better API choice: Gemini 3.8 Flash vs GPT-5.6 Luna Pro?
GPT-5.6 Luna Pro costs 73% less on input and 68% less on output than Gemini 3.8 Flash ($0.200 / $1.20 versus $0.750 / $3.75 per million tokens). GPT-5.6 Luna Pro accepts more context (1.1 M). On capabilities, only Gemini 3.8 Flash accepts audio. Gemini 3.8 Flash and GPT-5.6 Luna Pro offer a batch tier at half price for jobs that do not need an immediate answer.
Which is cheaper: Gemini 3.8 Flash and GPT-5.6 Luna Pro?
GPT-5.6 Luna Pro is cheaper: $0.200 per million input tokens and $1.20 per million output tokens, versus $0.750 / $3.75 for Gemini 3.8 Flash.
Which has more context: Gemini 3.8 Flash and GPT-5.6 Luna Pro?
GPT-5.6 Luna Pro accepts 1.1 M tokens of context; Gemini 3.8 Flash accepts 1 M.
Which is newer: Gemini 3.8 Flash and GPT-5.6 Luna Pro?
Gemini 3.8 Flash was released on 09/02/2026; GPT-5.6 Luna Pro on 07/09/2026.
What would 10,000 requests a month cost with Gemini 3.8 Flash and GPT-5.6 Luna Pro?
With 1,500 input and 400 output tokens per request: Gemini 3.8 Flash: $26.25; GPT-5.6 Luna Pro: $7.80 a month, at list price.
Where do the prices come from and how often are they updated?
From the public catalogs of OpenRouter, models.dev and LiteLLM, which publish each provider's list prices. They sync once a day and the last update date is shown above the comparison.
What does price per million tokens mean?
It is what the provider charges per million tokens you send (input) or the model generates (output). A token is roughly 4 characters. Output almost always costs more than input.
Sources: OpenRouter, models.dev and LiteLLM. Prices in USD per million tokens, list price, no volume discounts. Prompt tokens are an estimate; each provider's tokenizer may differ.