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GPT-5.6 Sol Pro vs Grok 4.20

GPT-5.6 Sol Pro

OpenAI

89#20
vs
Grok 4.20

xAI

88#22
Signal-by-Signal Comparison
SignalGPT-5.6 Sol ProDeltaGrok 4.20
Capabilities
100
--
100
Benchmarks
88
+1
86
Pricing
70
-27
98
Context window size
86
-4
90
Recency
100
--
100
Output Capacity
85
+65
20
Overall Result
2 wins
of 6
2 wins
It's a tie - both models win 2 signals each

Score History

Score History (15 data points)
GPT-5.6 Sol ProGrok 4.20
GPT-5.6 Sol Pro

88.5

current score

Leader

GPT-5.6 Sol Pro

right now

Grok 4.20

88.3

current score

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

GPT-5.6 Sol Pro

OpenAI

Per request$0.020000
Daily$66.67
Monthly$2000.00
Annual$24000.00

Grok 4.20

xAI

Best Value
Per request$0.002500
Daily$8.33
Monthly$250.00
Annual$3000.00

Grok 4.20 saves you $1750.00/month

That's $21000.00/year compared to GPT-5.6 Sol Pro at your current usage level of 100K calls/month.

88% cheaper
Choose Grok 4.20 for cost optimization

GPT-5.6 Sol Pro pricing:
Input:$5.00/M tokens
Output:$30.00/M tokens
Grok 4.20 pricing:
Input:$1.25/M tokens
Output:$2.50/M tokens
Winner
GPT-5.6 Sol Pro

OpenAI

89

Composite Score

Grok 4.20

xAI

88

Composite Score

Signal-by-Signal Comparison
MetricGPT-5.6 Sol ProGrok 4.20Winner
Overall Score
89
88
GPT-5.6 Sol Pro
Rank#20#22
GPT-5.6 Sol Pro
Quality Rank#20#22
GPT-5.6 Sol Pro
Adoption Rank#20#22
GPT-5.6 Sol Pro
Parameters------
Context Window1050K2000K
Grok 4.20
Pricing$5.00/$30.00/M$1.25/$2.50/M--
Signal Scores
Capabilities
100
100
GPT-5.6 Sol Pro
Benchmarks
88
86
GPT-5.6 Sol Pro
Pricing
70
98
Grok 4.20
Context window size
86
90
Grok 4.20
Recency
100
100
GPT-5.6 Sol Pro
Output Capacity
85
20
GPT-5.6 Sol Pro
Benchmark Head-to-Head(12 benchmarks)
GPT-5.6 Sol: 9Grok 4.20: 1
GPT-5.6 Sol
Grok 4.20
Normalized 0-100%
MMLU
93%91.5%
MMLU-Pro
84.5%83.5%
GPQA Diamond
85%82%
MATH-500
92.5%95%
HumanEval
96.5%95.5%
SWE-bench Verified
75%70%
AIME 2024
-88%
IFEval
92%91%
BBH
90.5%90%
Arena Elo
14651462
LiveBench
76%73%
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 Sol ProElite Tier

Scores 89/100 (rank #20), placing it in the top 93% of all 290 models tracked.

Raw Quality0/100
Cost Efficiency0/100
Speed0/100
Grok 4.20Elite Tier

Scores 88/100 (rank #22), placing it in the top 93% 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 Sol Pro when you need:

  • Step-by-step reasoning and chain-of-thought problem solving

Choose Grok 4.20 when you need:

  • High-volume production workloads where API costs must be minimized
  • Processing long documents or large codebases (2000K token context)
  • Step-by-step reasoning and chain-of-thought problem solving
Cost-Performance Analysis
GPT-5.6 Sol Pro
Input cost$5.00/M tokens
Output cost$30.00/M tokens
Cost per quality point$0.395
Est. monthly (1M tokens/day)$525.00
Grok 4.20Best Value
Input cost$1.25/M tokens
Output cost$2.50/M tokens
Cost per quality point$0.042
Est. monthly (1M tokens/day)$56.25

Grok 4.20 offers 89% better value per quality point. At 1M tokens/day, you'd spend $56.25/month with Grok 4.20 vs $525.00/month with GPT-5.6 Sol Pro - a $468.75 monthly difference.

Latency & Speed
GPT-5.6 Sol ProFaster
Speed score0/100
Grok 4.20
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 Sol Pro

Customer support chatbot

Suitable for user-facing chat with competitive response times. Grok 4.20 also offers lower per-token costs for high-volume support

GPT-5.6 Sol Pro

Long document analysis

Larger context window (2000K tokens) can process longer documents, contracts, and research papers in a single pass

Grok 4.20

Batch data extraction

Lower output pricing ($2.50/M) reduces costs when processing thousands of records daily

Grok 4.20

Creative writing & content

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

GPT-5.6 Sol Pro

Image understanding & OCR

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

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

GPT-5.6 Sol Pro and Grok 4.20 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 Sol Pro
Recommended

by OpenAI

  • Choose for Quality - Marginally better benchmark scores; both are excellent
  • 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

  • Choose for Cost - 89% lower pricing; better value at scale
Capability Comparison
CapabilityGPT-5.6 Sol ProGrok 4.20
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 Sol Pro

OpenAI

$45.00
estimated monthly cost

Grok 4.20

xAI

Best Value
$5.25
estimated monthly cost

Grok 4.20 saves you $39.75/month

That's 88% cheaper than GPT-5.6 Sol Pro 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 Sol ProGrok 4.20
Context Window1.1M2M
Max Output Tokens128,000--
Open SourceNoNo
CreatedJul 9, 2026Mar 31, 2026
Last updated: 14m ago

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