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AI Choice Engine

Model comparison

Gemini 3.1 Flash-Lite vs GPT-6 Luna

Google against OpenAI, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Google

Gemini 3.1 Flash-Lite

Budget

vs

OpenAI

GPT-6 Luna

Budget

AI model capability comparison
SpecificationGemini 3.1 Flash-LiteGPT-6 Luna
ProviderGoogleOpenAI
TierBudgetBudget
Context window1.05MWinner: 1.05M
Max output66KWinner: 128K
Input / 1M tokens$0.25Winner: $0.10
Output / 1M tokens$1.50Winner: $0.50
WeightsClosedClosed
ParametersNot disclosedUnverifiedGPT-6 low-cost tier
Reasoning levelsNot verifiedUnverifiednone, low, medium, high, xhigh, max
Modalitiestext, image, video, audio, pdftext, image
API model idgemini-3.1-flash-litegpt-6-luna
ReleasedMay 7, 2026September 22, 2026
Artificial Analysis Intelligence Index (2026-09-26)15.6Not verifiedUnverified
Artificial Analysis Intelligence Index [max] (2026-09-26)Not verifiedUnverified37.3
DeepSWE 1.1 [max] (2026-09-22)Not verifiedUnverified66.6

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

  • 2026-09-26
    Artificial Analysis

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check measuredAt.

  • 2026-09-22
    OpenAI — Introducing GPT-6 Sol and Luna (vendor; not yet on Datacurve's board)

    Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.

    Directly comparable

Pricing tiers

Gemini 3.1 Flash-Lite: $0.25 input (text, image, video; $0.50 audio) / $1.50 output per MTok; cached input $0.025. GA 2026-05-07 after a 2026-03-03 preview; shutdown no earlier than 2027-05-07.

GPT-6 Luna: Direct successor to GPT-5.6 Luna at half the price. Cached input $0.01/MTok; cache writes $0.125. Above 272K input the whole request bills $0.20/$0.75 ($0.02 cached). Batch/Flex $0.05/$0.25; Fast mode $0.20/$1.00. Knowledge cutoff May 18 2026.

BudgetRecord checked September 26, 2026

Gemini 3.1 Flash-Lite

Gemini 3.1 Flash-Lite is Google's cheapest current Gemini API model for high-volume, latency-sensitive pipelines.

Best for

  • High-volume extraction
  • Classification
  • Cheap multimodal input

Watch out

Google recommends 3.5 Flash-Lite for new work, and 3.1 Flash-Lite's earliest shutdown date is 2027-05-07; well behind Flash models on reasoning.

BudgetRecord checked September 26, 2026

GPT-6 Luna

GPT-6 Luna is OpenAI's cheapest current model at $0.10/$0.50 — the direct successor to GPT-5.6 Luna at half the price, with the full 1.05M-token context.

Best for

  • High-volume chat and extraction
  • Classification
  • Cost-capped agent loops

Watch out

Small tier: it matches GPT-5.6 Luna on the Artificial Analysis index but sits well below GPT-6 Sol on hard reasoning; the DeepSWE figure is vendor-reported at max effort.

When the cheaper one wins

GPT-6 Luna is cheaper on output at $0.50 per million tokens against $1.50 for Gemini 3.1 Flash-Lite — about 3.0×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 3/5 core specs verified on both sides — Not published for at least one side: parameter count, reasoning levels.
  • 1 shared named benchmark with differing scores — Measured on: Artificial Analysis Intelligence Index.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? Gemini 3.1 Flash-Lite · GPT-6 Luna

Common questions

Gemini 3.1 Flash-Lite vs GPT-6 Luna

Answered from the verified figures on this page rather than general guidance.

Is Gemini 3.1 Flash-Lite or GPT-6 Luna cheaper for input?
GPT-6 Luna is cheaper at $0.10 per million input tokens, against $0.25 for Gemini 3.1 Flash-Lite — roughly 2.5× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Gemini 3.1 Flash-Lite has tiered pricing: $0.25 input (text, image, video; $0.50 audio) / $1.50 output per MTok; cached input $0.025. GA 2026-05-07 after a 2026-03-03 preview; shutdown no earlier than 2027-05-07. GPT-6 Luna has tiered pricing: Direct successor to GPT-5.6 Luna at half the price. Cached input $0.01/MTok; cache writes $0.125. Above 272K input the whole request bills $0.20/$0.75 ($0.02 cached). Batch/Flex $0.05/$0.25; Fast mode $0.20/$1.00. Knowledge cutoff May 18 2026.
Is Gemini 3.1 Flash-Lite or GPT-6 Luna cheaper for output?
GPT-6 Luna is cheaper at $0.50 per million output tokens, against $1.50 for Gemini 3.1 Flash-Lite — roughly 3.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Gemini 3.1 Flash-Lite has tiered pricing: $0.25 input (text, image, video; $0.50 audio) / $1.50 output per MTok; cached input $0.025. GA 2026-05-07 after a 2026-03-03 preview; shutdown no earlier than 2027-05-07. GPT-6 Luna has tiered pricing: Direct successor to GPT-5.6 Luna at half the price. Cached input $0.01/MTok; cache writes $0.125. Above 272K input the whole request bills $0.20/$0.75 ($0.02 cached). Batch/Flex $0.05/$0.25; Fast mode $0.20/$1.00. Knowledge cutoff May 18 2026.
Which has the larger context window, Gemini 3.1 Flash-Lite or GPT-6 Luna?
Both accept about 1.05M tokens of context, so document length will not decide between them.
Should I use Gemini 3.1 Flash-Lite or GPT-6 Luna?
Both sit in the budget tier, so the choice usually comes down to price and context rather than capability. Gemini 3.1 Flash-Lite suits high-volume extraction; GPT-6 Luna suits high-volume chat and extraction.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: GPT-6 Luna costs $0.10 per 1M tokens versus $0.25 for Gemini 3.1 Flash-Lite — a 2.5x difference at the headline tier.
  • Context: GPT-6 Luna takes 1.05M against 1.05M for Gemini 3.1 Flash-Lite — only decisive if your prompts approach the smaller window.
  • Measured capability: GPT-6 Luna leads Artificial Analysis Intelligence Index 37.3 to 15.6 (measured 2026-09-26).
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