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Model comparison

GPT-5.5 vs Grok 4.5

Data verified

Head-to-head evidence from 25 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

GPT-5.5
OpenAI
73.51/100
Margin
3.2pts
winning →
76.72/100
0 category wins2 category wins

Public leaderboard positions: GPT-5.5 #9 (Estimated); Grok 4.5 #7 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. GPT-5.5 and Grok 4.5 share 25 comparable benchmark results. 2 of 8 categories are comparable. 32 results are unique to GPT-5.5; 3 to Grok 4.5.

Updated July 23, 2026
Shared results
25
GPT-5.5 only
32
Grok 4.5 only
3
Comparable categories
2 / 8

Pick Grok 4.5 if you want the stronger benchmark profile. GPT-5.5 only becomes the better choice if you need the larger 1M context window.

Confidence note. This is a partial-evidence comparison with 25 shared benchmark results across 5 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Grok 4.5 is clearly ahead on the BenchAlign aggregate, 76.72 to 73.51. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Grok 4.5's sharpest advantage is in coding, where it averages 64.7 against 58.6. The single biggest benchmark swing on the page is SWE-bench Pro, 58.6% to 64.7%.

GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $2.00 input / $6.00 output per 1M tokens for Grok 4.5. That is roughly 5.0x on output cost alone. GPT-5.5 gives you the larger context window at 1M, compared with 500K for Grok 4.5.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for GPT-5.5 and Grok 4.5
CategoryGPT-5.5ΔGrok 4.5
CodingGPT-5.558.6Margin→ 6.1Grok 4.564.7
AgenticGPT-5.581.6Margin→ 1.7Grok 4.583.3
ReasoningGPT-5.585.0MarginNo overlapGrok 4.5Not measured
KnowledgeGPT-5.557.8MarginNo overlapGrok 4.5Not measured
MathGPT-5.547.6MarginNo overlapGrok 4.5Not measured
MultimodalGPT-5.570.4MarginNo overlapGrok 4.5Not measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · GPT-5.5B · Grok 4.5

  1. SWE-bench Pro

    Coding
    Source ↗
    A 58.6%B 64.7%
    Winner: Grok 4.5Δ 6.1
    SWE-bench Pro: GPT-5.5 scored 58.6%; Grok 4.5 scored 64.7%. Grok 4.5 wins this benchmark.

  2. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 82%B 83.3%
    Winner: Grok 4.5Δ 1.3
    Terminal-Bench 2.0: GPT-5.5 scored 82%; Grok 4.5 scored 83.3%. Grok 4.5 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricGPT-5.5Grok 4.5Comparison
Input / output priceUSD per 1M tokensGPT-5.5$5 input / $30 outputGrok 4.5$2 input / $6 outputGrok 4.5 has the lower combined listed price.
Generation speedtokens per secondGPT-5.5Not availableGrok 4.5Not availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenGPT-5.5Not availableGrok 4.5Not availableA complete latency comparison is not available.
Context windowmaximum listed tokensGPT-5.51MGrok 4.5500KGPT-5.5 lists the larger context window.

Benchmark Deep Dive

AgenticGrok 4.5 wins
BenchmarkGPT-5.5Grok 4.5Result
Terminal-Bench 2.0Source 82%83.3%Grok 4.5 leads
CyberGymSource 81.8%—Not comparable
BrowseCompSource 84.4%—Not comparable
OSWorld-VerifiedSource 78.7%—Not comparable
MCP AtlasSource 75.3%—Not comparable
ToolathlonSource 55.6%—Not comparable
τ²-bench resultsSource 93.9%—Not comparable
AA Agentic IndexSource 44.9%45.7%Grok 4.5 leads
APEX-Agents-AASource 37.7%—Not comparable
GDPval-AASource 49.5%51.7%Grok 4.5 leads
GDPval-AASource 14901535Grok 4.5 leads
Gert LabsSource 72.93%—Not comparable
ResearchClawBenchSource 17.0%—Not comparable
OSWorld 2.0Source 13.0%—Not comparable
JobBenchSource 42.7%—Not comparable
ExploitGymSource 13.4%—Not comparable
AA BriefcaseSource 11541323Grok 4.5 leads
AA AutomationBenchSource 42.1%51.4%Grok 4.5 leads
AA EnterpriseOps-GymSource 46.6%40.8%GPT-5.5 leads
AA Harvey LABSource 86.3%92.4%Grok 4.5 leads
AA ITBenchSource 45.8%—Not comparable
AA Tau3 BankingSource 31.3%32.6%Grok 4.5 leads
terminalBenchHardSource 60.6%—Not comparable
aaTerminalBench21Source 84.3%81.6%GPT-5.5 leads
deepSweSource —53%Not comparable
CodingGrok 4.5 wins
BenchmarkGPT-5.5Grok 4.5Result
SWE-bench ProSource 58.6%64.7%Grok 4.5 leads
Terminal-Bench 2.0Source 82.0%83.3%Grok 4.5 leads
Vibe Code BenchSource 69.85%—Not comparable
React Native EvalsSource 84.7%—Not comparable
cursorBench31Source 59.2%—Not comparable
cursorBench32Source 58.4%66.7%Grok 4.5 leads
AA Coding IndexSource 74.9%72.5%GPT-5.5 leads
AA-SciCodeSource 56.1%54.1%GPT-5.5 leads
FrontierCode 1.1 MainSource 43.0%—Not comparable
SWE MultilingualSource —78%Not comparable
VulcanBench v3Source —91.3%Not comparable
Reasoning
BenchmarkGPT-5.5Grok 4.5Result
MRCR v2 64K-128KSource 83.1%—Not comparable
MRCR v2 128K-256KSource 87.5%—Not comparable
ARC-AGI-2Source 85%—Not comparable
AA-LCRSource 74.3%67.7%GPT-5.5 leads
CritPtSource 27.1%15.4%GPT-5.5 leads
Knowledge
BenchmarkGPT-5.5Grok 4.5Result
GPQASource 93.6%—Not comparable
GPQA-DSource 93.6%—Not comparable
HLESource 52.2%—Not comparable
HLE w/o toolsSource 41.4%—Not comparable
Artificial Analysis Intelligence IndexSource 54.8%53.8%GPT-5.5 leads
AA-GPQA DiamondSource 93.5%93.1%GPT-5.5 leads
AA-HLESource 44.3%40.3%GPT-5.5 leads
AA-Omniscience IndexSource 20.1%26.4%Grok 4.5 leads
AA-Omniscience AccuracySource 56.9%52.1%GPT-5.5 leads
AA-Omniscience Hallucination RateSource 85.5%53.5%Grok 4.5 leads
Math
BenchmarkGPT-5.5Grok 4.5Result
FrontierMath (legacy)Source 51.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 51.700%—Not comparable
FrontierMath v2 (Tier 4)Source 35.400%—Not comparable
Multimodal
BenchmarkGPT-5.5Grok 4.5Result
MMMU-ProSource 81.2%—Not comparable
MMMU-Pro w/ PythonSource 83.2%—Not comparable
OfficeQA ProSource 54.1%—Not comparable
AA-MMMU-ProSource 79.9%80.4%Grok 4.5 leads
Design Arena WebsiteSource 12821325Grok 4.5 leads
Inst. Following
BenchmarkGPT-5.5Grok 4.5Result
AA-IFBenchSource 75.9%—Not comparable
Frequently Asked Questions (3)

Which is better, GPT-5.5 or Grok 4.5?

Grok 4.5 is ahead on BenchLM's BenchAlign leaderboard, 76.72 to 73.51. The biggest single separator in this matchup is SWE-bench Pro, where the scores are 58.6% and 64.7%.

Which is better for coding, GPT-5.5 or Grok 4.5?

Grok 4.5 has the edge for coding in this comparison, averaging 64.7 versus 58.6. Inside this category, cursorBench32 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.5 or Grok 4.5?

Grok 4.5 has the edge for agentic tasks in this comparison, averaging 83.3 versus 81.6. Inside this category, AA Briefcase is the benchmark that creates the most daylight between them.

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