Skip to main content
Van Data Team

text model comparison

Gemini 3.8 Flash vs GPT-5.6 Luna

Gemini 3.8 Flash and GPT-5.6 Luna are both current text models, from Google and OpenAI. GPT-5.6 Luna is 73% cheaper per 1M input tokens than Gemini 3.8 Flash, $0.20 vs $0.75. On Arena Text, Gemini 3.8 Flash scores 1496 Elo and GPT-5.6 Luna 1453 Elo (Arena, measured October 28, 2026). Both accept about 1.05M tokens of context (1,050,000 and 1,048,576).

Higher Arena Text
Gemini 3.8 Flash1496 Elo against 1453 Elo
Lower price per 1M input tokens
GPT-5.6 Luna$0.20 against $0.75
Longer context window
GPT-5.6 Luna1.05M tokens against 1.05M tokens
Newer release
Gemini 3.8 FlashSep 2026 against Jul 2026

Data verified November 3, 2026 · Dataset 2026-11-03

Share this

Side by side

Gemini 3.8 Flash and GPT-5.6 Luna, line by line

Prices in effect today, compared at the same tier wherever both list one. The better value in each row is highlighted.

FactGemini 3.8 FlashGPT-5.6 Luna
Price
Price per 1M input tokens$0.75$0.20 (better)
Price per 1M output tokens$3.75$1.20 (better)
Independent benchmarks
Arena Text1496 Elo (#6 of 51) (better)1453 Elo (#33 of 51)
FrontierMath Tiers 1-3 (v2)68.4% (#26 of 42)82.1% (#14 of 42) (better)
GPQA Diamond95.4% (#4 of 41) (better)91.6% (#21 of 41)
SimpleQA Verified69.7% (#8 of 38) (better)41% (#29 of 38)
Arena WebDev1583 Elo (#25 of 45)Not measured
Specs
ProviderGoogleOpenAI
Release dateSeptember 2, 2026July 9, 2026
AccessAPI onlyAPI only
Context window1,048,576 tokens1,050,000 tokens
Max output65,536 tokens128,000 tokens
Inputtext, image, audio, videotext, image
Outputtexttext

Scores:Arena · 2026-11-03Epoch AI · 2026-11-03

Open both in the interactive comparison

Charts

Against every current text model

Where Gemini 3.8 Flash and GPT-5.6 Luna land among the current models of their task, on every independent benchmark, on price and on context.

Where each stands

On Arena Text, Gemini 3.8 Flash ranks #6 and GPT-5.6 Luna #33 of 51 current models. Each bar is the share of current models it beats: on score, price and context.

Gemini 3.8 Flash and GPT-5.6 Luna among the current text models, one row per benchmark, price and context window.

Independent benchmarks

Arena Text

Gemini 3.8 Flash:#6of 51

1,496 Elo · ahead of 90%

GPT-5.6 Luna:#33of 51

1,453 Elo · ahead of 36%

Arena WebDev

Gemini 3.8 Flash:#25of 45

1,583 Elo · ahead of 45%

GPT-5.6 Luna: Not scored

FrontierMath Tiers 1-3 (v2)

Gemini 3.8 Flash:#26of 42

68.4% · ahead of 39%

GPT-5.6 Luna:#14of 42

82.1% · ahead of 66%

GPQA Diamond

Gemini 3.8 Flash:#4of 41

95.4% · ahead of 90%

GPT-5.6 Luna:#21of 41

91.6% · ahead of 50%

SimpleQA Verified

Gemini 3.8 Flash:#8of 38

69.7% · ahead of 78%

GPT-5.6 Luna:#29of 38

41% · ahead of 22%

Price and context

Price per 1M input tokens

Gemini 3.8 Flash:#20of 52

$0.75 · cheaper than 63%

GPT-5.6 Luna:#7of 52

$0.20 · cheaper than 84%

Price per 1M output tokens

Gemini 3.8 Flash:#23of 52

$3.75 · cheaper than 57%

GPT-5.6 Luna:#10of 52

$1.20 · cheaper than 76%

Context window

Gemini 3.8 Flash:#11of 64

1.05M tokens · longer than 67%

GPT-5.6 Luna:#1of 64

1.05M tokens · longer than 86%

Scores fromArena · 2026-11-03Epoch AI · 2026-11-03

Quality against price

Arena Text · measured October 28, 2026

Gemini 3.8 Flash scores 1,496 at $1.50; GPT-5.6 Luna scores 1,453 at $0.45 (blended price per 1M tokens). The line joins the current models no other beats on both price and Arena Text score; hover any point to name it.

Quality against priceArena Text score against price for 43 text models, Gemini 3.8 Flash and GPT-5.6 Luna marked.1,2501,3001,3501,4001,4501,5001,550$0.30$1$3$10MOST ATTRACTIVE QUADRANTMedian price $3Median 1,475Blended price per 1M tokens (3 input : 1 output), log scaleArena Text (Elo)Gemini 3.8 FlashGPT-5.6 Luna
Quality against price: the data
Arena Text score against price for 43 text models, Gemini 3.8 Flash and GPT-5.6 Luna marked.
ModelProviderBlended price per 1M tokensArena Text (Elo)
Gemini 4 ArgonGoogle$41,520
Claude Opus 5.5Anthropic$81,509
Muse WonderMeta$81,507
Claude Fable 5Anthropic$201,504
Claude Fable 5.1Anthropic$201,504
Gemini 3.8 FlashGoogle$1.501,496
Muse Spark 1.3Meta$21,495
Claude Opus 5Anthropic$101,492
Kimi K3Moonshot Kimi$61,488
GPT-5.6 SolOpenAI$81,485
Gemini 3.6 FlashGoogle$31,483
GPT-5.5OpenAI$111,482
Claude Opus 4.8Anthropic$101,482
Qwen3.8-MaxAlibaba Qwen$31,482
GPT-6.1 SolOpenAI$41,481
GLM-5.3Z.ai$2.151,481
MiMo-V2.6-ProXiaomi MiMo$0.541,480
Claude Sonnet 5.5Anthropic$41,477
GLM-5.3-FlashZ.ai$0.241,477
GPT-6 AstraOpenAI$201,476
DeepSeek-V4.1-FlashDeepSeek$0.521,476
GPT-5.4OpenAI$5.631,475
Gemini 3 Flash PreviewGoogle$1.131,473
Grok 4.20xAI$1.561,472
GPT-5.6 TerraOpenAI$4.501,467
Grok 4.5xAI$31,465
DeepSeek-V4-ProDeepSeek$1.981,465
Claude Sonnet 5Anthropic$41,462
GPT-6 SolOpenAI$41,458
Gemini 3.5 Flash-LiteGoogle$0.851,456
Grok 4.6xAI$31,455
GPT-5.6 LunaOpenAI$0.451,453
MiMo-V2.6-FlashXiaomi MiMo$0.181,448
Step 5 PreviewStepFun$1.431,448
Grok 4.3xAI$1.561,442
GPT-6 LunaOpenAI$0.201,441
Grok 4.7xAI$31,441
Mistral Large 4Mistral AI$1.051,432
Claude Haiku 5.5Anthropic$0.201,425
GPT-4.1OpenAI$3.501,415
Solar Pro 4Upstage$0.521,388
GPT-4.1 miniOpenAI$0.701,383
GPT-4.1 nanoOpenAI$0.181,322

Cost

What each costs

Example workloads at each provider's listed rates, then every other rate either one lists. The cheaper figure in each row is highlighted.

The same work, priced

For 10M input and 2M output tokens, Gemini 3.8 Flash costs 3.4 times as much as GPT-5.6 Luna, at each provider's listed rates.

What Gemini 3.8 Flash and GPT-5.6 Luna cost for the same work, at the rates each provider lists.

  • 10M input and 2M output tokens

    Gemini 3.8 Flash costs 3.4× as much

    Gemini 3.8 Flash
    $15
    GPT-5.6 Luna
    $4.40

  • The same, with 9M of the input tokens cached

    Gemini 3.8 Flash costs 3.2× as much

    Gemini 3.8 Flash
    $8.93
    GPT-5.6 Luna
    $2.78
Workload or rateGemini 3.8 FlashGPT-5.6 Luna
Example workloads
10M input and 2M output tokens$15$4.40 (better)
The same, with 9M of the input tokens cached$8.93$2.78 (better)
The same, through the batch API$7.50Not listed
Other listed rates
1M input tokens, cached$0.075$0.02 (better)
1M input tokens, batch$0.375Not listed
1M output tokens, batch$1.875Not listed
1M input tokens, priority$1.35Not listed
1M output tokens, priority$6.75Not listed

Your own bill will differ. These figures use list prices and example workloads. The AI Model Cost Audit reviews your real usage, shortlists models that score as well for each task for less, and estimates the savings.

Launch price $100, regular price $150

Book the cost audit

Verdict

When to choose each

Gemini 3.8 Flash

Where it leads

  • Higher Arena Text score, 1496 Elo vs 1453 Elo
  • Higher GPQA Diamond score, 95.4% vs 91.6%
  • Higher SimpleQA Verified score, 69.7% vs 41%
  • Accepts audio and video input
  • Batch pricing, $0.375 input and $1.875 output per 1M tokens

Best for

  • High-volume agentic and coding workloads where per-token cost dominates the decision
  • Multimodal pipelines that need audio, video and PDF input in one model

Watch out for

  • The listed price is promotional and ends 31 December 2026; on 1 January 2027 input and output both double, to $1.50 and $7.50, and cached input goes from $0.075 to $0.15
  • Output pricing is billed inclusive of thinking tokens, so reasoning-heavy prompts cost more than the output length suggests
  • Google’s published comparisons are against its own previous Flash release and were not independently reproduced here
Full Gemini 3.8 Flash profile

GPT-5.6 Luna

Where it leads

  • Lower input and output prices, $0.20 and $1.20 vs $0.75 and $3.75 per 1M tokens
  • Higher FrontierMath Tiers 1-3 (v2) score, 82.1% vs 68.4%
  • Longer responses, up to 128,000 vs 65,536 output tokens
  • Cheaper cached input, $0.02 vs $0.075 per 1M tokens

Best for

  • High-volume API evaluation with published low token prices
  • Subagents and batch reasoning where cost per call dominates

Watch out for

  • Not in the pinned LiveBench snapshot; its independent scores here come from Epoch AI's own GPQA Diamond, FrontierMath and SimpleQA Verified runs
Full GPT-5.6 Luna profile

From benchmark to production

Building on Gemini 3.8 Flash or GPT-5.6 Luna?

Public scores rarely hold on your own data. We test both models on your real tasks, then build the agent or pipeline around the one that wins.

AI Model Cost AuditLaunch price $100, regular price $150What the audit includes

Book the cost auditAI agent development

FAQ

Gemini 3.8 Flash vs GPT-5.6 Luna FAQ

Which is cheaper, Gemini 3.8 Flash or GPT-5.6 Luna?

GPT-5.6 Luna is 73% cheaper per 1M input tokens than Gemini 3.8 Flash, $0.20 vs $0.75. For 10M input and 2M output tokens, Gemini 3.8 Flash costs $15 and GPT-5.6 Luna $4.40 at standard rates.

Which is cheaper with prompt caching, Gemini 3.8 Flash or GPT-5.6 Luna?

Gemini 3.8 Flash charges $0.075 per 1M cached input tokens, 90% below its standard input rate, and GPT-5.6 Luna $0.02, 90% below. With 9M of 10M input tokens cached and 2M output tokens, Gemini 3.8 Flash costs $8.93 and GPT-5.6 Luna $2.78.

Which scores higher on independent benchmarks, Gemini 3.8 Flash or GPT-5.6 Luna?

Gemini 3.8 Flash leads on Arena Text, 1496 Elo to 1453 Elo; GPT-5.6 Luna leads on FrontierMath Tiers 1-3 (v2), 82.1% to 68.4%; Gemini 3.8 Flash leads on GPQA Diamond, 95.4% to 91.6%. Scores are independent evaluations, not either vendor's launch figures.

Which has the larger context window, Gemini 3.8 Flash or GPT-5.6 Luna?

Both accept about 1.05M tokens of context (1,050,000 and 1,048,576). GPT-5.6 Luna returns up to 128,000 tokens per response, Gemini 3.8 Flash 65,536.

How do Gemini 3.8 Flash and GPT-5.6 Luna differ in features?

Gemini 3.8 Flash takes text, image, audio and video input; GPT-5.6 Luna takes text and image.

Further reading

More on Gemini 3.8 Flash and GPT-5.6 Luna

Articles on Gemini 3.8 Flash and GPT-5.6 Luna

Related comparisons

Production evaluation

Choosing between Gemini 3.8 Flash and GPT-5.6 Luna?

Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.

  • A head-to-head evaluation on your real workload
  • Routing between models by cost and difficulty
Compare all modelsBook a consultation