Gemini 3.8 Flash vs GPT-6 Luna

Compare Gemini 3.8 Flash from Google and GPT-6 Luna from OpenAI on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.

Gemini 3.8 Flash vs GPT-6 Luna: side-by-side summary

Gemini 3.8 Flash and GPT-6 Luna are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Gemini 3.8 Flash, from Google, has a 1,048,576-token context window and is priced at $0.75/M tokens input, $3.75/M tokens output on OpenRouter.

GPT-6 Luna, from OpenAI, has a 1,050,000-token context window and is priced at $0.10/M tokens input, $0.50/M tokens output on OpenRouter.

Context window

Gemini 3.8 Flash: 1,048,576 tokens
GPT-6 Luna: 1,050,000 tokens

Price

Gemini 3.8 Flash: $0.75/M tokens input, $3.75/M tokens output
GPT-6 Luna: $0.10/M tokens input, $0.50/M tokens output

Provided by

Gemini 3.8 Flash: Google
GPT-6 Luna: OpenAI

Gemini 3.8 Flash vs GPT-6 Luna at a glance

Gemini 3.8 Flash vs GPT-6 Luna comparison
Attribute	Gemini 3.8 Flash	GPT-6 Luna
Input price	$0.75/M tokens	$0.10/M tokens
Output price	$3.75/M tokens	$0.50/M tokens
Context window	1,048,576 tokens	1,050,000 tokens
Intelligence Index	40.9	38.1
Coding Index	76.3	Not available
Agentic Index	40.2	Not available
Latency (p50)	2.16 s	2.62 s
Throughput (p50)	81.0 tok/s	67.0 tok/s

Benchmark data updated Oct 5, 2026

Frequently asked questions

Which has the longer context window, Gemini 3.8 Flash or GPT-6 Luna?

GPT-6 Luna has the longer context window at 1,050,000 tokens, compared with 1,048,576 tokens for Gemini 3.8 Flash.

Which is faster, Gemini 3.8 Flash or GPT-6 Luna?

Gemini 3.8 Flash is faster on OpenRouter, generating a median 81.0 tokens per second compared with 67.0 tokens per second for GPT-6 Luna.

Gemini 3.8 Flash vs GPT-6 Luna

Gemini 3.8 Flash vs GPT-6 Luna

Overview