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GPT-5.6 Luna Pro vs Grok 4.5

GPT-5.6 Luna Pro

OpenAI

89#21
vs
Grok 4.5

xAI

89#27
Signal-by-Signal Comparison
SignalGPT-5.6 Luna ProDeltaGrok 4.5
Capabilities
100
--
100
Benchmarks
88
+12
76
Pricing
99
+5
94
Context window size
96
+5
90
Recency
100
--
100
Output Capacity
85
+65
20
Overall Result
4 wins
of 6
0 wins
GPT-5.6 Luna Pro wins 4 of 6 signals

Score History

Score History (5 data points)
GPT-5.6 Luna ProGrok 4.5
GPT-5.6 Luna Pro

89

current score

Leader

GPT-5.6 Luna Pro

right now

Grok 4.5

88.8

current score

LMMarketCap.com
Interactive Price Comparison
100Kcalls/month
1,000tokens (~1,333 chars)
500tokens (~667 chars)

GPT-5.6 Luna Pro

OpenAI

Best Value
Per request$0.000400
Daily$1.33
Monthly$40.00
Annual$480.00

Grok 4.5

xAI

Per request$0.005000
Daily$16.67
Monthly$500.00
Annual$6000.00

GPT-5.6 Luna Pro saves you $460.00/month

That's $5520.00/year compared to Grok 4.5 at your current usage level of 100K calls/month.

92% cheaper
Choose GPT-5.6 Luna Pro for cost optimization

GPT-5.6 Luna Pro pricing:
Input:$0.10/M tokens
Output:$0.60/M tokens
Grok 4.5 pricing:
Input:$2.00/M tokens
Output:$6.00/M tokens
Winner
GPT-5.6 Luna Pro

OpenAI

89

Composite Score

Grok 4.5

xAI

89

Composite Score

Signal-by-Signal Comparison
MetricGPT-5.6 Luna ProGrok 4.5Winner
Overall Score
89
89
GPT-5.6 Luna Pro
Rank#21#27
GPT-5.6 Luna Pro
Quality Rank#21#27
GPT-5.6 Luna Pro
Adoption Rank#21#27
GPT-5.6 Luna Pro
Parameters------
Context Window1050K500K
GPT-5.6 Luna Pro
Pricing$0.10/$0.60/M$2.00/$6.00/M--
Signal Scores
Capabilities
100
100
GPT-5.6 Luna Pro
Benchmarks
88
76
GPT-5.6 Luna Pro
Pricing
99
94
GPT-5.6 Luna Pro
Context window size
96
90
GPT-5.6 Luna Pro
Recency
100
100
GPT-5.6 Luna Pro
Output Capacity
85
20
GPT-5.6 Luna Pro
Benchmark Head-to-Head(11 benchmarks)
GPT-5.6 Luna: 0Grok 4.5: 1
GPT-5.6 Luna
Grok 4.5
Normalized 0-100%
MMLU
93%-
MMLU-Pro
84.5%-
GPQA Diamond
85%-
MATH-500
92.5%-
HumanEval
96.5%-
SWE-bench Verified
75%-
IFEval
92%-
BBH
90.5%-
Arena Elo
14651469
LiveBench
76%-
HLE
35%-
Benchmark Interpretation

Our score (0-100) is driven by benchmark performance (90%) from Arena Elo ratings, MMLU, GPQA, HumanEval, SWE-bench, and 15+ standardized evaluations. Capabilities and context window serve as tiebreakers (10%). Learn more about our methodology.

GPT-5.6 Luna ProElite Tier

Scores 89/100 (rank #21), placing it in the top 93% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100
Grok 4.5Elite Tier

Scores 89/100 (rank #27), placing it in the top 91% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100

With only a 0-point gap, these models are in the same performance tier. The practical difference in output quality is minimal - your choice should depend on pricing, latency requirements, and specific feature needs.

When to Use Each Model

Choose GPT-5.6 Luna Pro when you need:

  • High-volume production workloads where API costs must be minimized
  • Processing long documents or large codebases (1050K token context)
  • Step-by-step reasoning and chain-of-thought problem solving

Choose Grok 4.5 when you need:

  • Step-by-step reasoning and chain-of-thought problem solving
Cost-Performance Analysis
GPT-5.6 Luna ProBest Value
Input cost$0.10/M tokens
Output cost$0.60/M tokens
Cost per quality point$0.008
Est. monthly (1M tokens/day)$10.50
Grok 4.5
Input cost$2.00/M tokens
Output cost$6.00/M tokens
Cost per quality point$0.090
Est. monthly (1M tokens/day)$120.00

GPT-5.6 Luna Pro offers 91% better value per quality point. At 1M tokens/day, you'd spend $10.50/month with GPT-5.6 Luna Pro vs $120.00/month with Grok 4.5 - a $109.50 monthly difference.

Latency & Speed
GPT-5.6 Luna ProFaster
Speed score0/100
Grok 4.5
Speed score0/100

Both models have comparable response speeds. For most applications, the latency difference is negligible.

When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.

Example Use Cases

Code generation & review

Based on overall model capabilities and architecture for coding tasks like generating functions, debugging, and refactoring

GPT-5.6 Luna Pro

Customer support chatbot

Suitable for user-facing chat with competitive response times. GPT-5.6 Luna Pro also offers lower per-token costs for high-volume support

GPT-5.6 Luna Pro

Long document analysis

Larger context window (1050K tokens) can process longer documents, contracts, and research papers in a single pass

GPT-5.6 Luna Pro

Batch data extraction

Lower output pricing ($0.60/M) reduces costs when processing thousands of records daily

GPT-5.6 Luna Pro

Creative writing & content

Higher overall composite score (89/100) correlates with better nuance, coherence, and style in long-form content

GPT-5.6 Luna Pro

Image understanding & OCR

Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly

GPT-5.6 Luna Pro
Which Should You Choose?
Our recommendation:
GPT-5.6 Luna Pro

GPT-5.6 Luna Pro and Grok 4.5 are extremely close in overall performance (only 0.20000000000000284 points apart). Your best choice depends entirely on which specific strengths matter most for your use case.

GPT-5.6 Luna Pro
Recommended

by OpenAI

  • Choose for Quality - Marginally better benchmark scores; both are excellent
  • Choose for Cost - 91% lower pricing; better value at scale
  • Choose for Reliability - Higher uptime and faster response speeds
  • Choose for Prototyping - Stronger community support and better developer experience
  • Choose for Production - Wider enterprise adoption and proven at scale

by xAI

Consider for specialized use cases.

Capability Comparison
CapabilityGPT-5.6 Luna ProGrok 4.5
Vision (Image Input)
Function Calling
Streaming
JSON Mode
Reasoning
Web Search
Image Output
Monthly Cost Calculator
1,000tokens (600 in / 400 out)
100requests/day (3,000/month)

GPT-5.6 Luna Pro

OpenAI

Best Value
$0.9000
estimated monthly cost

Grok 4.5

xAI

$10.80
estimated monthly cost

GPT-5.6 Luna Pro saves you $9.90/month

That's 92% cheaper than Grok 4.5 at 1,000 tokens/request and 100 requests/day.

Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.

Parameters & Context
ParameterGPT-5.6 Luna ProGrok 4.5
Context Window1.1M500K
Max Output Tokens128,000--
Open SourceNoNo
CreatedJul 9, 2026Jul 8, 2026
Last updated: 1h ago

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