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Van Data Team

text model comparison

GPT-5.6 Luna vs GPT-6 Sol

GPT-5.6 Luna and GPT-6 Sol are both current text models, from OpenAI. GPT-5.6 Luna is 90% cheaper per 1M input tokens than GPT-6 Sol, $0.20 vs $2. On Arena Text, GPT-5.6 Luna scores 1452 Elo and GPT-6 Sol 1456 Elo (Arena, measured October 8, 2026). Both accept 1,050,000 tokens of context.

Higher Arena Text
GPT-6 Sol1456 Elo against 1452 Elo
Lower price per 1M input tokens
GPT-5.6 Luna$0.20 against $2
Newer release
GPT-6 SolSep 2026 against Jul 2026

Data verified October 13, 2026 · Dataset 2026-10-28

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Side by side

GPT-5.6 Luna and GPT-6 Sol, line by line

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

FactGPT-5.6 LunaGPT-6 Sol
Price
Price per 1M input tokens$0.20 (better)$2
Price per 1M output tokens$1.20 (better)$10
Independent benchmarks
Arena Text1452 Elo (#34 of 49)1456 Elo (#31 of 49) (better)
GPQA Diamond91.6% (#20 of 40)94.3% (#7 of 40) (better)
FrontierMath Tiers 1-3 (v2)82.1% (#12 of 40)89.8% (#5 of 40) (better)
SimpleQA Verified41% (#27 of 36)60.7% (#14 of 36) (better)
Specs
ProviderOpenAIOpenAI
Release dateJuly 9, 2026September 22, 2026
AccessAPI onlyAPI only
Context window1,050,000 tokens1,050,000 tokens
Max output128,000 tokens128,000 tokens
Inputtext, imagetext, image
Outputtexttext

Scores:Arena · 2026-10-12Epoch AI · 2026-10-12

Open both in the interactive comparison

Charts

Against every current text model

Where GPT-5.6 Luna and GPT-6 Sol land among the current models of their task, on every independent benchmark, on price and on context.

Where each stands

On Arena Text, GPT-5.6 Luna ranks #34 and GPT-6 Sol #31 of 49 current models. Each bar is the share of current models it beats: on score, price and context.

GPT-5.6 Luna and GPT-6 Sol among the current text models, one row per benchmark, price and context window.

Independent benchmarks

Arena Text

GPT-5.6 Luna:#34of 49

1,452 Elo · ahead of 31%

GPT-6 Sol:#31of 49

1,456 Elo · ahead of 38%

GPQA Diamond

GPT-5.6 Luna:#20of 40

91.6% · ahead of 51%

GPT-6 Sol:#7of 40

94.3% · ahead of 85%

FrontierMath Tiers 1-3 (v2)

GPT-5.6 Luna:#12of 40

82.1% · ahead of 72%

GPT-6 Sol:#5of 40

89.8% · ahead of 90%

SimpleQA Verified

GPT-5.6 Luna:#27of 36

41% · ahead of 23%

GPT-6 Sol:#14of 36

60.7% · ahead of 63%

Price and context

Price per 1M input tokens

GPT-5.6 Luna:#7of 51

$0.20 · cheaper than 84%

GPT-6 Sol:#28of 51

$2 · cheaper than 24%

Price per 1M output tokens

GPT-5.6 Luna:#10of 51

$1.20 · cheaper than 78%

GPT-6 Sol:#33of 51

$10 · cheaper than 26%

Context window

GPT-5.6 Luna:#1of 66

1.05M tokens · longer than 86%

GPT-6 Sol:#1of 66

1.05M tokens · longer than 86%

Scores fromArena · 2026-10-12Epoch AI · 2026-10-12

Quality against price

Arena Text · measured October 8, 2026

GPT-5.6 Luna scores 1,452 at $0.45; GPT-6 Sol scores 1,456 at $4 (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 41 text models, GPT-5.6 Luna and GPT-6 Sol 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)GPT-6 SolGPT-5.6 Luna
Quality against price: the data
Arena Text score against price for 41 text models, GPT-5.6 Luna and GPT-6 Sol marked.
ModelProviderBlended price per 1M tokensArena Text (Elo)
Gemini 4 ArgonGoogle$41,525
Claude Opus 5.5Anthropic$81,507
Claude Fable 5Anthropic$201,504
Claude Fable 5.1Anthropic$201,501
Gemini 3.8 FlashGoogle$1.501,497
Muse Spark 1.3Meta$21,494
Claude Opus 5Anthropic$101,490
Kimi K3Moonshot Kimi$61,488
Gemini 3.7 FlashGoogle$1.501,486
GPT-5.6 SolOpenAI$81,485
GPT-6.1 SolOpenAI$41,484
Qwen3.8-MaxAlibaba Qwen$31,483
GPT-5.5OpenAI$111,482
Gemini 3.6 FlashGoogle$31,482
Claude Opus 4.8Anthropic$101,481
MiMo-V2.6-ProXiaomi MiMo$0.541,480
GLM-5.3Z.ai$2.151,478
Claude Sonnet 5.5Anthropic$41,476
GPT-5.4OpenAI$5.631,475
GPT-6 AstraOpenAI$201,475
DeepSeek-V4.1-FlashDeepSeek$0.521,475
GLM-5.3-FlashZ.ai$0.241,475
Gemini 3 Flash PreviewGoogle$1.131,473
Grok 4.20xAI$1.561,472
GPT-5.6 TerraOpenAI$4.501,466
Grok 4.5xAI$31,466
DeepSeek-V4-ProDeepSeek$1.981,465
Claude Sonnet 5Anthropic$41,461
GPT-6 SolOpenAI$41,456
Gemini 3.5 Flash-LiteGoogle$0.851,455
Grok 4.6xAI$31,454
GPT-5.6 LunaOpenAI$0.451,452
MiMo-V2.6-FlashXiaomi MiMo$0.181,451
GPT-6 LunaOpenAI$0.201,443
Grok 4.7xAI$31,443
Grok 4.3xAI$1.561,442
Mistral Large 4Mistral AI$2.061,429
GPT-4.1OpenAI$3.501,415
Solar Pro 4Upstage$0.521,386
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, GPT-6 Sol costs 9.1 times as much as GPT-5.6 Luna, at each provider's listed rates.

What GPT-5.6 Luna and GPT-6 Solcost for the same work, at each provider's listed rates.

  • 10M input and 2M output tokens

    GPT-6 Sol costs 9.1× as much

    GPT-5.6 Luna
    $4.40
    GPT-6 Sol
    $40

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

    GPT-6 Sol costs 8.6× as much

    GPT-5.6 Luna
    $2.78
    GPT-6 Sol
    $23.80
Workload or rateGPT-5.6 LunaGPT-6 Sol
Example workloads
10M input and 2M output tokens$4.40 (better)$40
The same, with 9M of the input tokens cached$2.78 (better)$23.80
Other listed rates
1M input tokens, cached$0.02 (better)$0.20
1M input tokens, prompts over 272K tokensNot listed$4
1M output tokens, prompts over 272K tokensNot listed$15

Verdict

When to choose each

GPT-5.6 Luna

Where it leads

  • Lower input and output prices, $0.20 and $1.20 vs $2 and $10 per 1M tokens
  • Cheaper cached input, $0.02 vs $0.20 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

GPT-6 Sol

Where it leads

  • Higher Arena Text score, 1456 Elo vs 1452 Elo
  • Higher GPQA Diamond score, 94.3% vs 91.6%
  • Higher FrontierMath Tiers 1-3 (v2) score, 89.8% vs 82.1%
  • Higher SimpleQA Verified score, 60.7% vs 41%

Best for

  • General production work that does not need Astra's capability or price
  • Workloads kept under the 272,000-token threshold

Watch out for

  • Prompts over 272,000 input tokens are rebilled for the whole request at $4 input and $15 output, so crossing the line roughly doubles input cost
  • GPT-6.1 Sol lists the same base rates with half the cached-input price, so there is little reason to pick this one for a cache-heavy workload
Full GPT-6 Sol profile

From benchmark to production

Building on GPT-5.6 Luna or GPT-6 Sol?

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.

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FAQ

GPT-5.6 Luna vs GPT-6 Sol FAQ

Which is cheaper, GPT-5.6 Luna or GPT-6 Sol?

GPT-5.6 Luna is 90% cheaper per 1M input tokens than GPT-6 Sol, $0.20 vs $2. For 10M input and 2M output tokens, GPT-5.6 Luna costs $4.40 and GPT-6 Sol $40 at standard rates.

Which is cheaper with prompt caching, GPT-5.6 Luna or GPT-6 Sol?

GPT-5.6 Luna charges $0.02 per 1M cached input tokens, 90% below its standard input rate, and GPT-6 Sol $0.20, 90% below. With 9M of 10M input tokens cached and 2M output tokens, GPT-5.6 Luna costs $2.78 and GPT-6 Sol $23.80.

Which scores higher on independent benchmarks, GPT-5.6 Luna or GPT-6 Sol?

GPT-6 Sol leads on Arena Text, 1456 Elo to 1452 Elo; GPT-6 Sol leads on GPQA Diamond, 94.3% to 91.6%; GPT-6 Sol leads on FrontierMath Tiers 1-3 (v2), 89.8% to 82.1%. Scores are independent evaluations, not either vendor's launch figures.

Which has the larger context window, GPT-5.6 Luna or GPT-6 Sol?

Both accept 1,050,000 tokens of context. Both return up to 128,000 tokens per response.

Further reading

More on GPT-5.6 Luna and GPT-6 Sol

Articles on GPT-5.6 Luna and GPT-6 Sol

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Production evaluation

Choosing between GPT-5.6 Luna and GPT-6 Sol?

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
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