text model comparison
Claude Opus 5 vs GPT-5.6 Luna
Claude Opus 5 and GPT-5.6 Luna are both current text models, from Anthropic and OpenAI. GPT-5.6 Luna is 96% cheaper per 1M input tokens than Claude Opus 5, $0.20 vs $5. On Arena Text, Claude Opus 5 scores 1490 Elo and GPT-5.6 Luna 1452 Elo (Arena, measured October 8, 2026). GPT-5.6 Luna has the larger context window, 1,050,000 vs 1,000,000 tokens.
- Higher Arena Text
- Claude Opus 51490 Elo against 1452 Elo
- Lower price per 1M input tokens
- GPT-5.6 Luna$0.20 against $5
- Longer context window
- GPT-5.6 Luna1.05M tokens against 1M tokens
- Newer release
- Claude Opus 5Jul 2026 against Jul 2026
Data verified October 12, 2026 · Dataset 2026-10-28
Side by side
Claude Opus 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.
| Fact | Claude Opus 5 | GPT-5.6 Luna |
|---|---|---|
| Price | ||
| Price per 1M input tokens | $5 | $0.20 (better) |
| Price per 1M output tokens | $25 | $1.20 (better) |
| Independent benchmarks | ||
| Arena Text | 1490 Elo (#7 of 49) (better) | 1452 Elo (#34 of 49) |
| GPQA Diamond | 93.9% (#10 of 40) (better) | 91.6% (#20 of 40) |
| FrontierMath Tiers 1-3 (v2) | 85.6% (#10 of 40) (better) | 82.1% (#12 of 40) |
| SimpleQA Verified | 59.9% (#15 of 36) (better) | 41% (#27 of 36) |
| Specs | ||
| Provider | Anthropic | OpenAI |
| Release date | July 24, 2026 | July 9, 2026 |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image | text, image |
| Output | text | text |
Charts
Against every current text model
Where Claude Opus 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 Opus 5 ranks #7 and GPT-5.6 Luna #34 of 49 current models. Each bar is the share of current models it beats: on score, price and context.
Independent benchmarks
Arena Text
Claude Opus 5:#7of 49
1,490 Elo · ahead of 88%
GPT-5.6 Luna:#34of 49
1,452 Elo · ahead of 31%
GPQA Diamond
Claude Opus 5:#10of 40
93.9% · ahead of 77%
GPT-5.6 Luna:#20of 40
91.6% · ahead of 51%
FrontierMath Tiers 1-3 (v2)
Claude Opus 5:#10of 40
85.6% · ahead of 77%
GPT-5.6 Luna:#12of 40
82.1% · ahead of 72%
SimpleQA Verified
Claude Opus 5:#15of 36
59.9% · ahead of 60%
GPT-5.6 Luna:#27of 36
41% · ahead of 23%
Price and context
Price per 1M input tokens
Claude Opus 5:#45of 51
$5 · cheaper than 8%
GPT-5.6 Luna:#7of 51
$0.20 · cheaper than 84%
Price per 1M output tokens
Claude Opus 5:#45of 51
$25 · cheaper than 10%
GPT-5.6 Luna:#10of 51
$1.20 · cheaper than 78%
Context window
Claude Opus 5:#28of 66
1M tokens · longer than 22%
GPT-5.6 Luna:#1of 66
1.05M tokens · longer than 86%
Quality against price
Claude Opus 5 scores 1,490 at $10; GPT-5.6 Luna scores 1,452 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 price: the data
| Model | Provider | Blended price per 1M tokens | Arena Text (Elo) |
|---|---|---|---|
| Gemini 4 Argon | $4 | 1,525 | |
| Claude Opus 5.5 | Anthropic | $8 | 1,507 |
| Claude Fable 5 | Anthropic | $20 | 1,504 |
| Claude Fable 5.1 | Anthropic | $20 | 1,501 |
| Gemini 3.8 Flash | $1.50 | 1,497 | |
| Muse Spark 1.3 | Meta | $2 | 1,494 |
| Claude Opus 5 | Anthropic | $10 | 1,490 |
| Kimi K3 | Moonshot Kimi | $6 | 1,488 |
| Gemini 3.7 Flash | $1.50 | 1,486 | |
| GPT-5.6 Sol | OpenAI | $8 | 1,485 |
| GPT-6.1 Sol | OpenAI | $4 | 1,484 |
| Qwen3.8-Max | Alibaba Qwen | $3 | 1,483 |
| GPT-5.5 | OpenAI | $11 | 1,482 |
| Gemini 3.6 Flash | $3 | 1,482 | |
| Claude Opus 4.8 | Anthropic | $10 | 1,481 |
| MiMo-V2.6-Pro | Xiaomi MiMo | $0.54 | 1,480 |
| GLM-5.3 | Z.ai | $2.15 | 1,478 |
| Claude Sonnet 5.5 | Anthropic | $4 | 1,476 |
| GPT-5.4 | OpenAI | $5.63 | 1,475 |
| GPT-6 Astra | OpenAI | $20 | 1,475 |
| DeepSeek-V4.1-Flash | DeepSeek | $0.52 | 1,475 |
| GLM-5.3-Flash | Z.ai | $0.24 | 1,475 |
| Gemini 3 Flash Preview | $1.13 | 1,473 | |
| Grok 4.20 | xAI | $1.56 | 1,472 |
| GPT-5.6 Terra | OpenAI | $4.50 | 1,466 |
| Grok 4.5 | xAI | $3 | 1,466 |
| DeepSeek-V4-Pro | DeepSeek | $1.98 | 1,465 |
| Claude Sonnet 5 | Anthropic | $4 | 1,461 |
| GPT-6 Sol | OpenAI | $4 | 1,456 |
| Gemini 3.5 Flash-Lite | $0.85 | 1,455 | |
| Grok 4.6 | xAI | $3 | 1,454 |
| GPT-5.6 Luna | OpenAI | $0.45 | 1,452 |
| MiMo-V2.6-Flash | Xiaomi MiMo | $0.18 | 1,451 |
| GPT-6 Luna | OpenAI | $0.20 | 1,443 |
| Grok 4.7 | xAI | $3 | 1,443 |
| Grok 4.3 | xAI | $1.56 | 1,442 |
| Mistral Large 4 | Mistral AI | $2.06 | 1,429 |
| GPT-4.1 | OpenAI | $3.50 | 1,415 |
| Solar Pro 4 | Upstage | $0.52 | 1,386 |
| GPT-4.1 mini | OpenAI | $0.70 | 1,383 |
| GPT-4.1 nano | OpenAI | $0.18 | 1,322 |
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 Opus 5 costs 23 times as much as GPT-5.6 Luna, at each provider's listed rates.
10M input and 2M output tokens
Claude Opus 5 costs 23× as much
- Claude Opus 5
- $100
- GPT-5.6 Luna
- $4.40
The same, with 9M of the input tokens cached
Claude Opus 5 costs 21× as much
- Claude Opus 5
- $59.50
- GPT-5.6 Luna
- $2.78
| Workload or rate | Claude Opus 5 | GPT-5.6 Luna |
|---|---|---|
| Example workloads | ||
| 10M input and 2M output tokens | $100 | $4.40 (better) |
| The same, with 9M of the input tokens cached | $59.50 | $2.78 (better) |
| The same, through the batch API | $50 | Not listed |
| Other listed rates | ||
| 1M input tokens, cached | $0.50 | $0.02 (better) |
| 1M input tokens, batch | $2.50 | Not listed |
| 1M output tokens, batch | $12.50 | Not listed |
Verdict
When to choose each
Claude Opus 5
Where it leads
- Higher Arena Text score, 1490 Elo vs 1452 Elo
- Higher GPQA Diamond score, 93.9% vs 91.6%
- Higher FrontierMath Tiers 1-3 (v2) score, 85.6% vs 82.1%
- Higher SimpleQA Verified score, 59.9% vs 41%
- Batch pricing, $2.50 input and $12.50 output per 1M tokens
Best for
- Complex agentic coding and enterprise work as the general-purpose default before reaching for Fable 5.1
- Latency-sensitive work that can justify Fast mode pricing
Watch out for
- Fast mode pricing applies to the whole request, including above 200K input tokens, so it doubles the effective rate rather than adding a surcharge
- Cache reads are $0.50 per million (the standard 0.1x), five times Fable 5.1’s $0.25, even though Opus 5 is the cheaper model on base tokens. A cache-heavy agent loop can invert the expected cost ordering between the two.
GPT-5.6 Luna
Where it leads
- Lower input and output prices, $0.20 and $1.20 vs $5 and $25 per 1M tokens
- Larger context window 1,050,000 vs 1,000,000 tokens
- Cheaper cached input, $0.02 vs $0.50 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
From benchmark to production
Building on Claude Opus 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.
FAQ
Claude Opus 5 vs GPT-5.6 Luna FAQ
Which is cheaper, Claude Opus 5 or GPT-5.6 Luna?
GPT-5.6 Luna is 96% cheaper per 1M input tokens than Claude Opus 5, $0.20 vs $5. For 10M input and 2M output tokens, Claude Opus 5 costs $100 and GPT-5.6 Luna $4.40 at standard rates.
Which is cheaper with prompt caching, Claude Opus 5 or GPT-5.6 Luna?
Claude Opus 5 charges $0.50 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, Claude Opus 5 costs $59.50 and GPT-5.6 Luna $2.78.
Which scores higher on independent benchmarks, Claude Opus 5 or GPT-5.6 Luna?
Claude Opus 5 leads on Arena Text, 1490 Elo to 1452 Elo; Claude Opus 5 leads on GPQA Diamond, 93.9% to 91.6%; Claude Opus 5 leads on FrontierMath Tiers 1-3 (v2), 85.6% to 82.1%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, Claude Opus 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 Opus 5 and GPT-5.6 Luna
Articles on Claude Opus 5 and GPT-5.6 Luna
- Fable 5.1 vs Opus 5 vs GPT-5.6: Which to UseSeptember 1, 2026
- Kimi K3 vs Opus 5 vs GPT-5.6 Sol: which model should you use?July 31, 2026
- Gemini 3.6 Flash vs Claude Opus 5: Route by TierJuly 26, 2026
- Claude Opus 5: What Anthropic's New Flagship Means for AI AgentsJuly 26, 2026
- GPT-5.6 on Azure Databricks: Production Guide for AI TeamsJuly 11, 2026
- GPT-5.6 In Microsoft 365 Copilot: What Production Teams Should KnowJuly 10, 2026
Related comparisons
- Claude Opus 5 vs Claude Opus 5.5
- GPT-5.6 Luna vs GPT-6 Luna
- Claude Opus 5 vs Gemini 3.8 Flash
- GPT-5.6 Luna vs GPT-6 Sol
- Claude Fable 5 vs Claude Opus 5
- GPT-5.6 Luna vs Grok 4.6
- Claude Opus 4.8 vs Claude Opus 5
- Gemini 3.6 Flash vs GPT-5.6 Luna
- Claude Opus 5 vs Gemini 3.6 Flash
- GPT-5.6 Luna vs GPT-5.6 Sol
- Claude Opus 5 vs GPT-5.5
- GPT-5.6 Luna vs GPT-5.6 Terra
Production evaluation
Choosing between Claude Opus 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