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text model comparison

Claude Sonnet 5.5 vs GPT-5.6 Luna

Claude Sonnet 5.5 and GPT-5.6 Luna are both current text models, from Anthropic and OpenAI. GPT-5.6 Luna is 90% cheaper per 1M input tokens than Claude Sonnet 5.5, $0.20 vs $2. On Arena Text, Claude Sonnet 5.5 scores 1477 Elo and GPT-5.6 Luna 1453 Elo (Arena, measured October 28, 2026). GPT-5.6 Luna has the larger context window, 1,050,000 vs 1,000,000 tokens.

Higher Arena Text
Claude Sonnet 5.51477 Elo against 1453 Elo
Lower price per 1M input tokens
GPT-5.6 Luna$0.20 against $2
Longer context window
GPT-5.6 Luna1.05M tokens against 1M tokens
Newer release
Claude Sonnet 5.5Sep 2026 against Jul 2026

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

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Side by side

Claude Sonnet 5.5 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.

FactClaude Sonnet 5.5GPT-5.6 Luna
Price
Price per 1M input tokens$2$0.20 (better)
Price per 1M output tokens$10$1.20 (better)
Independent benchmarks
Arena Text1477 Elo (#19 of 51) (better)1453 Elo (#33 of 51)
FrontierMath Tiers 1-3 (v2)88.8% (#8 of 42) (better)82.1% (#14 of 42)
GPQA Diamond95.6% (#3 of 41) (better)91.6% (#21 of 41)
SimpleQA Verified46.5% (#23 of 38) (better)41% (#29 of 38)
Arena WebDev1770 Elo (#3 of 45)Not measured
Specs
ProviderAnthropicOpenAI
Release dateSeptember 28, 2026July 9, 2026
AccessAPI onlyAPI only
Context window1,000,000 tokens1,050,000 tokens
Max output128,000 tokens128,000 tokens
Inputtext, imagetext, image
Outputtexttext

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

Open both in the interactive comparison

Charts

Against every current text model

Where Claude Sonnet 5.5 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, Claude Sonnet 5.5 ranks #19 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.

Claude Sonnet 5.5 and GPT-5.6 Luna among the current text models, one row per benchmark, price and context window.

Independent benchmarks

Arena Text

Claude Sonnet 5.5:#19of 51

1,477 Elo · ahead of 62%

GPT-5.6 Luna:#33of 51

1,453 Elo · ahead of 36%

Arena WebDev

Claude Sonnet 5.5:#3of 45

1,770 Elo · ahead of 95%

GPT-5.6 Luna: Not scored

FrontierMath Tiers 1-3 (v2)

Claude Sonnet 5.5:#8of 42

88.8% · ahead of 83%

GPT-5.6 Luna:#14of 42

82.1% · ahead of 66%

GPQA Diamond

Claude Sonnet 5.5:#3of 41

95.6% · ahead of 95%

GPT-5.6 Luna:#21of 41

91.6% · ahead of 50%

SimpleQA Verified

Claude Sonnet 5.5:#23of 38

46.5% · ahead of 41%

GPT-5.6 Luna:#29of 38

41% · ahead of 22%

Price and context

Price per 1M input tokens

Claude Sonnet 5.5:#29of 52

$2 · cheaper than 24%

GPT-5.6 Luna:#7of 52

$0.20 · cheaper than 84%

Price per 1M output tokens

Claude Sonnet 5.5:#34of 52

$10 · cheaper than 25%

GPT-5.6 Luna:#10of 52

$1.20 · cheaper than 76%

Context window

Claude Sonnet 5.5:#26of 64

1M tokens · longer than 22%

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

Claude Sonnet 5.5 scores 1,477 at $4; 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, Claude Sonnet 5.5 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)Claude Sonnet 5.5GPT-5.6 Luna
Quality against price: the data
Arena Text score against price for 43 text models, Claude Sonnet 5.5 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, Claude Sonnet 5.5 costs 9.1 times as much as GPT-5.6 Luna, at each provider's listed rates.

What Claude Sonnet 5.5 and GPT-5.6 Luna cost for the same work, at the rates each provider lists.

  • 10M input and 2M output tokens

    Claude Sonnet 5.5 costs 9.1× as much

    Claude Sonnet 5.5
    $40
    GPT-5.6 Luna
    $4.40

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

    Claude Sonnet 5.5 costs 8.2× as much

    Claude Sonnet 5.5
    $22.90
    GPT-5.6 Luna
    $2.78
Workload or rateClaude Sonnet 5.5GPT-5.6 Luna
Example workloads
10M input and 2M output tokens$40$4.40 (better)
The same, with 9M of the input tokens cached$22.90$2.78 (better)
The same, through the batch API$20Not listed
Other listed rates
1M input tokens, cached$0.10$0.02 (better)
1M input tokens, 5-minute cache write$2.50Not listed
1M input tokens, 1-hour cache write$4Not listed
1M input tokens, batch$1Not listed
1M output tokens, batch$5Not 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

Claude Sonnet 5.5

Where it leads

  • Higher Arena Text score, 1477 Elo vs 1453 Elo
  • Higher FrontierMath Tiers 1-3 (v2) score, 88.8% vs 82.1%
  • Higher GPQA Diamond score, 95.6% vs 91.6%
  • Higher SimpleQA Verified score, 46.5% vs 41%
  • Batch pricing, $1 input and $5 output per 1M tokens

Best for

  • Production workloads that need frontier-adjacent quality at a mid-tier rate
  • Latency-sensitive agent steps inside a larger pipeline

Watch out for

  • Same list price as Claude Sonnet 5, so the gain is capability and cache economics rather than a cheaper rate card
  • Anthropic positions Opus 5.5 rather than this as the default, so reach for Sonnet 5.5 when latency matters more than peak capability
Full Claude Sonnet 5.5 profile

GPT-5.6 Luna

Where it leads

  • Lower input and output prices, $0.20 and $1.20 vs $2 and $10 per 1M tokens
  • Larger context window 1,050,000 vs 1,000,000 tokens
  • Cheaper cached input, $0.02 vs $0.10 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 Claude Sonnet 5.5 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

Claude Sonnet 5.5 vs GPT-5.6 Luna FAQ

Which is cheaper, Claude Sonnet 5.5 or GPT-5.6 Luna?

GPT-5.6 Luna is 90% cheaper per 1M input tokens than Claude Sonnet 5.5, $0.20 vs $2. For 10M input and 2M output tokens, Claude Sonnet 5.5 costs $40 and GPT-5.6 Luna $4.40 at standard rates.

Which is cheaper with prompt caching, Claude Sonnet 5.5 or GPT-5.6 Luna?

Claude Sonnet 5.5 charges $0.10 per 1M cached input tokens, 95% 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, Claude Sonnet 5.5 costs $22.90 and GPT-5.6 Luna $2.78.

Which scores higher on independent benchmarks, Claude Sonnet 5.5 or GPT-5.6 Luna?

Claude Sonnet 5.5 leads on Arena Text, 1477 Elo to 1453 Elo; Claude Sonnet 5.5 leads on FrontierMath Tiers 1-3 (v2), 88.8% to 82.1%; Claude Sonnet 5.5 leads on GPQA Diamond, 95.6% to 91.6%. Scores are independent evaluations, not either vendor's launch figures.

Which has the larger context window, Claude Sonnet 5.5 or GPT-5.6 Luna?

GPT-5.6 Luna has the larger context window, 1,050,000 vs 1,000,000 tokens. Both return up to 128,000 tokens per response.

Further reading

More on Claude Sonnet 5.5 and GPT-5.6 Luna

Articles on Claude Sonnet 5.5 and GPT-5.6 Luna

Related comparisons

Production evaluation

Choosing between Claude Sonnet 5.5 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
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