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Model comparison

Claude Opus 4.5 vs GPT-5.5 Pro

Data verified

Head-to-head evidence from 4 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.22/100
Margin
0.5pts
← winning
63.69/100
2 category wins1 category wins

Public leaderboard positions: Claude Opus 4.5 #34 (Supported); GPT-5.5 Pro #38 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.5 and GPT-5.5 Pro share 4 comparable benchmark results. 3 of 8 categories are comparable. 55 results are unique to Claude Opus 4.5; 3 to GPT-5.5 Pro.

Updated July 23, 2026
Shared results
4
Claude Opus 4.5 only
55
GPT-5.5 Pro only
3
Comparable categories
3 / 8

Pick Claude Opus 4.5 if you want the stronger benchmark profile. GPT-5.5 Pro only becomes the better choice if agentic is the priority or you need the larger 1M context window.

Confidence note. This is a partial-evidence comparison with 4 shared benchmark results across 3 evidence categories; 3 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Opus 4.5 has the cleaner BenchAlign overall profile here, landing at 64.22 versus 63.69. It is a real lead, but still close enough that category-level strengths matter more than the headline number.

Claude Opus 4.5's sharpest advantage is in mathematics, where it averages 57.5 against 48.1. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 4.167% to 39.600%. GPT-5.5 Pro does hit back in agentic, so the answer changes if that is the part of the workload you care about most.

GPT-5.5 Pro is also the more expensive model on tokens at $30.00 input / $180.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.5. That is roughly 7.2x on output cost alone. GPT-5.5 Pro is the reasoning model in the pair, while Claude Opus 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. GPT-5.5 Pro gives you the larger context window at 1M, compared with 200K for Claude Opus 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 Claude Opus 4.5 and GPT-5.5 Pro
CategoryClaude Opus 4.5ΔGPT-5.5 Pro
AgenticClaude Opus 4.562.6Margin→ 27.5GPT-5.5 Pro90.1
MathClaude Opus 4.557.5Margin← 9.4GPT-5.5 Pro48.1
KnowledgeClaude Opus 4.558.1Margin← 0.9GPT-5.5 Pro57.2
CodingClaude Opus 4.571.7MarginNo overlapGPT-5.5 ProNot measured
ReasoningClaude Opus 4.564.4MarginNo overlapGPT-5.5 ProNot measured
MultilingualClaude Opus 4.585.7MarginNo overlapGPT-5.5 ProNot measured
MultimodalClaude Opus 4.569.9MarginNo overlapGPT-5.5 ProNot measured
Inst. FollowingClaude Opus 4.569.5MarginNo overlapGPT-5.5 ProNot measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.5B · GPT-5.5 Pro

  1. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 4.167%B 39.600%
    Winner: GPT-5.5 ProΔ 35.4
    FrontierMath v2 (Tier 4): Claude Opus 4.5 scored 4.167%; GPT-5.5 Pro scored 39.600%. GPT-5.5 Pro wins this benchmark.

  2. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 20.690%B 51.000%
    Winner: GPT-5.5 ProΔ 30.3
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.5 scored 20.690%; GPT-5.5 Pro scored 51.000%. GPT-5.5 Pro wins this benchmark.

  3. HLE

    Knowledge
    Source ↗
    A 30.8%B 57.2%
    Winner: GPT-5.5 ProΔ 26.4
    HLE: Claude Opus 4.5 scored 30.8%; GPT-5.5 Pro scored 57.2%. GPT-5.5 Pro wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.5GPT-5.5 ProComparison
Input / output priceUSD per 1M tokensClaude Opus 4.5$5 input / $25 outputGPT-5.5 Pro$30 input / $180 outputClaude Opus 4.5 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.546 tok/sGPT-5.5 ProNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.51.01 sGPT-5.5 ProNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.5200KGPT-5.5 Pro1MGPT-5.5 Pro lists the larger context window.

Benchmark Deep Dive

AgenticGPT-5.5 Pro wins
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
Terminal-Bench 2.0Source 59.3%—Not comparable
OSWorld-VerifiedSource 66.3%—Not comparable
OSWorldSource 66.3%—Not comparable
Claw-EvalSource 59.6%—Not comparable
QwenClawBenchSource 52.3%—Not comparable
τ³-bench resultsSource 70.2%—Not comparable
VITA-BenchSource 23.3%—Not comparable
DeepPlanningSource 26.4%—Not comparable
ToolathlonSource 43.5%—Not comparable
MCP AtlasSource 42.3%—Not comparable
MCP-TasksSource 71.8%—Not comparable
WideResearchSource 76.4%—Not comparable
CyberGymSource 50.6%—Not comparable
τ²-bench resultsSource 86.3%—Not comparable
Gert LabsSource 64.23%—Not comparable
JobBenchSource 32.3%—Not comparable
BrowseCompSource —90.1%Not comparable
Coding
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
SWE-bench VerifiedSource 80.9%—Not comparable
LiveCodeBench v6Source 84.8%—Not comparable
SWE-bench ProSource 57.1%—Not comparable
SWE MultilingualSource 77.5%—Not comparable
NL2RepoSource 43.2%—Not comparable
AA-SciCodeSource 47.0%—Not comparable
Reasoning
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
LongBench v2Source 64.4%—Not comparable
AI-NeedleSource 74%—Not comparable
AA-LCRSource 65.3%—Not comparable
CritPtSource 0.3%30.6%GPT-5.5 Pro leads
KnowledgeClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
GPQASource 87%—Not comparable
SuperGPQASource 70.6%—Not comparable
MMLU-ProSource 89.5%—Not comparable
MMLU-ReduxSource 96.6%—Not comparable
C-EvalSource 92.2%—Not comparable
HLESource 30.8%57.2%GPT-5.5 Pro leads
Artificial Analysis Intelligence IndexSource 34.7%—Not comparable
AA-GPQA DiamondSource 81.0%—Not comparable
AA-HLESource 12.9%—Not comparable
AA-Omniscience IndexSource -3.9%—Not comparable
AA-Omniscience AccuracySource 40.7%—Not comparable
AA-Omniscience Hallucination RateSource 75.4%—Not comparable
AA MMLU-ProSource 88.9%—Not comparable
HLE w/o toolsSource —43.1%Not comparable
MathClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
AIME26Source 95.1%—Not comparable
HMMT Feb 2025Source 92.9%—Not comparable
HMMT Nov 2025Source 93.3%—Not comparable
HMMT Feb 2026Source 85.3%—Not comparable
MMAnswerBenchSource 84.0%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 20.690%51.000%GPT-5.5 Pro leads
FrontierMath v2 (Tier 4)Source 4.167%39.600%GPT-5.5 Pro leads
FrontierMath (legacy)Source —52.4%Not comparable
Multilingual
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
MMLU-ProXSource 85.7%—Not comparable
NOVA-63Source 56.7%—Not comparable
Multimodal
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
MMMU-ProSource 70.6%—Not comparable
MathVisionSource 74.3%—Not comparable
CharXivSource 68.5%—Not comparable
VideoMMMUSource 84.4%—Not comparable
ScreenSpot ProSource 45.7%—Not comparable
V*Source 67.0%—Not comparable
AA-MMMU-ProSource 71.2%—Not comparable
Design Arena WebsiteSource 1277—Not comparable
Inst. Following
BenchmarkClaude Opus 4.5GPT-5.5 ProResult
IFEvalSource 90.9%—Not comparable
IFBenchSource 58%—Not comparable
AA-IFBenchSource 43.0%—Not comparable
Frequently Asked Questions (4)

Which is better, Claude Opus 4.5 or GPT-5.5 Pro?

Claude Opus 4.5 is ahead on BenchLM's BenchAlign leaderboard, 64.22 to 63.69. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 4.167% and 39.600%.

Which is better for knowledge tasks, Claude Opus 4.5 or GPT-5.5 Pro?

Claude Opus 4.5 has the edge for knowledge tasks in this comparison, averaging 58.1 versus 57.2. Inside this category, HLE is the benchmark that creates the most daylight between them.

Which is better for math, Claude Opus 4.5 or GPT-5.5 Pro?

Claude Opus 4.5 has the edge for math in this comparison, averaging 57.5 versus 48.1. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude Opus 4.5 or GPT-5.5 Pro?

GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 62.6. Claude Opus 4.5 stays close enough that the answer can still flip depending on your workload.

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