AI model comparison

GPT-6 Luna vs Gemma 4 31B

Side by side comparison of GPT-6 Luna and Gemma 4 31B on pricing, benchmark scores, context window, and more.

GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol.

Input / 1M
$0.10
Output / 1M
$0.50
Context
1.05M

Gemma 4 31B Instruct is Google DeepMind's 30.7B dense multimodal model supporting text and image input with text output.

Input / 1M
$0.20
Output / 1M
$0.40
Context
262K

Comparing image generators? Compare image models

At a glance

Quick verdict

How the two models stack up on the things people ask about most.

Lower price

openai logo

GPT-6 Luna

1.3x cheaper for a typical chat

Higher intelligence score

Not available

Not enough benchmark data

Larger context window

openai logo

GPT-6 Luna

1.05M vs 262K tokens

Newer release

openai logo

GPT-6 Luna

Released September 22, 2026

Benchmarks

Benchmark scores

Independent scores from Artificial Analysis. Higher is better.

Intelligence index

openai logoGPT-6 Luna27.8
google logoGemma 4 31BNot available

Coding index

openai logoGPT-6 LunaNot available
google logoGemma 4 31B43.4

Agentic index

openai logoGPT-6 LunaNot available
google logoGemma 4 31B4.2

Pricing

GPT-6 Luna vs Gemma 4 31B API pricing

Per-token API rates. Cheaper option highlighted.

Metricopenai logoGPT-6 Lunagoogle logoGemma 4 31B
Input tokensPer 1M tokens$0.10$0.20
Output tokensPer 1M tokens$0.50$0.40
Cached input (read)Per 1M tokens$0.01Not available
Cache writePer 1M tokens$0.13Not available
Long-context pricingPer 1M tokens, for very long prompts$0.20 in / $0.75 out above 272KSame rate at any length
Web searchPer request$0.01Not available

What it costs in practice

Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.

Chat message

2K in, 500 out

openai logoGPT-6 Luna$0.45
google logoGemma 4 31B$0.60

Coding task

30K in, 4K out

openai logoGPT-6 Luna$5$2.30 cached
google logoGemma 4 31B$7.60

Long document summary

150K in, 2K out

openai logoGPT-6 Luna$16$2.50 cached
google logoGemma 4 31B$30.80

Specs

Context window and capabilities

How much each model can read, how much it can write, and what it accepts as input.

Metricopenai logoGPT-6 Lunagoogle logoGemma 4 31B
Context window1.05M tokens262K tokens
Max output128K tokens16K tokens
Input typesFile, Image, TextImage, Text, Video
Output typesTextText
Reasoning effort levelsMax, Extra high, High, Medium, Low, NoneNot available
Default reasoning effortMediumNot available
Release dateSeptember 22, 2026April 2, 2026

Features

Supported features

API features available for each model.

Metricopenai logoGPT-6 Lunagoogle logoGemma 4 31B
Tool callingSupportedSupported
Structured outputsSupportedSupported
JSON modeSupportedSupported
ReasoningSupportedSupported
TemperatureNot supportedSupported
Stop sequencesNot supportedSupported
Deterministic seedSupportedSupported
Verbosity controlSupportedNot supported

Our take

GPT-6 Luna is 1.3x cheaper for a typical chat. GPT-6 Luna has the larger context window (1.05M vs 262K tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.

FAQ

Frequently asked questions

Is GPT-6 Luna or Gemma 4 31B cheaper?

GPT-6 Luna is cheaper for a typical chat (2K input tokens and 500 output tokens). GPT-6 Luna costs $0.10 per 1M input tokens and $0.50 per 1M output tokens, while Gemma 4 31B costs $0.20 per 1M input tokens and $0.40 per 1M output tokens.

Which has a bigger context window, GPT-6 Luna or Gemma 4 31B?

GPT-6 Luna supports up to 1.05M tokens of context, compared with 262K for Gemma 4 31B.

Can I use GPT-6 Luna and Gemma 4 31B at the same time?

Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see GPT-6 Luna and Gemma 4 31B answer side by side and keep the better response.

openai logogoogle logo

Why choose? Ask both.

Send one prompt to GPT-6 Luna and Gemma 4 31B at the same time. Compare the answers side by side and keep the best one.