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Model comparison

Claude Opus 4.5 vs GPT-5.1

Data verified

Head-to-head evidence from 16 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

64.22/100
Margin
10.6pts
← winning
GPT-5.1
OpenAI
53.65/100
1 category wins0 category wins

Public leaderboard positions: Claude Opus 4.5 #34 (Supported); GPT-5.1 #94 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Opus 4.5 and GPT-5.1 share 16 comparable benchmark results. 1 of 8 categories are comparable. 43 results are unique to Claude Opus 4.5; 5 to GPT-5.1.

Updated July 20, 2026
Shared results
16
Claude Opus 4.5 only
43
GPT-5.1 only
5
Comparable categories
1 / 8

Pick Claude Opus 4.5 if you want the stronger benchmark profile. GPT-5.1 only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.

Confidence note. This is a partial-evidence comparison with 16 shared benchmark results across 7 evidence categories; 1 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 is clearly ahead on the BenchAlign aggregate, 64.22 to 53.65. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Opus 4.5's sharpest advantage is in mathematics, where it averages 57.5 against 26.4. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 20.690% to 31.034%.

Claude Opus 4.5 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $1.25 input / $10.00 output per 1M tokens for GPT-5.1. That is roughly 2.5x on output cost alone. GPT-5.1 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.

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-5.1
CategoryClaude Opus 4.5ΔGPT-5.1
MathClaude Opus 4.557.5Margin← 31.1GPT-5.126.4
AgenticClaude Opus 4.562.6MarginNo overlapGPT-5.1Not measured
CodingClaude Opus 4.571.7MarginNo overlapGPT-5.1Not measured
ReasoningClaude Opus 4.564.4MarginNo overlapGPT-5.1Not measured
KnowledgeClaude Opus 4.558.1MarginNo overlapGPT-5.1Not measured
MultilingualClaude Opus 4.585.7MarginNo overlapGPT-5.1Not measured
MultimodalClaude Opus 4.569.9MarginNo overlapGPT-5.1Not measured
Inst. FollowingClaude Opus 4.569.5MarginNo overlapGPT-5.1Not measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.5B · GPT-5.1

  1. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 20.690%B 31.034%
    Winner: GPT-5.1Δ 10.3
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.5 scored 20.690%; GPT-5.1 scored 31.034%. GPT-5.1 wins this benchmark.

  2. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 4.167%B 12.500%
    Winner: GPT-5.1Δ 8.3
    FrontierMath v2 (Tier 4): Claude Opus 4.5 scored 4.167%; GPT-5.1 scored 12.500%. GPT-5.1 wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.5GPT-5.1Comparison
Input / output priceUSD per 1M tokensClaude Opus 4.5$5 input / $25 outputGPT-5.1$1.25 input / $10 outputGPT-5.1 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.546 tok/sGPT-5.1111 tok/sGPT-5.1 has the higher measured throughput.
First-answer latencyseconds to first tokenClaude Opus 4.51.01 sGPT-5.157.47 sClaude Opus 4.5 reaches the first token sooner.
Context windowmaximum listed tokensClaude Opus 4.5200KGPT-5.1200KListed context windows are equal.

Benchmark Deep Dive

Agentic
BenchmarkClaude Opus 4.5GPT-5.1Result
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%81.9%Claude Opus 4.5 leads
Gert LabsSource 64.23%41.24%Claude Opus 4.5 leads
JobBenchSource 32.3%—Not comparable
AA Agentic IndexSource —21.0%Not comparable
GDPval-AASource —24.4%Not comparable
GDPval-AASource —987Not comparable
Coding
BenchmarkClaude Opus 4.5GPT-5.1Result
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%43.3%Claude Opus 4.5 leads
Vibe Code BenchSource —24.61%Not comparable
AA Coding IndexSource —49.4%Not comparable
Reasoning
BenchmarkClaude Opus 4.5GPT-5.1Result
LongBench v2Source 64.4%—Not comparable
AI-NeedleSource 74%—Not comparable
AA-LCRSource 65.3%75.0%GPT-5.1 leads
CritPtSource 0.3%4.9%GPT-5.1 leads
Knowledge
BenchmarkClaude Opus 4.5GPT-5.1Result
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%—Not comparable
Artificial Analysis Intelligence IndexSource 34.7%36.9%GPT-5.1 leads
AA-GPQA DiamondSource 81.0%87.3%GPT-5.1 leads
AA-HLESource 12.9%26.5%GPT-5.1 leads
AA-Omniscience IndexSource -3.9%5.6%GPT-5.1 leads
AA-Omniscience AccuracySource 40.7%37.6%Claude Opus 4.5 leads
AA-Omniscience Hallucination RateSource 75.4%51.3%GPT-5.1 leads
AA MMLU-ProSource 88.9%—Not comparable
MathClaude Opus 4.5 wins
BenchmarkClaude Opus 4.5GPT-5.1Result
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%31.034%GPT-5.1 leads
FrontierMath v2 (Tier 4)Source 4.167%12.500%GPT-5.1 leads
Multilingual
BenchmarkClaude Opus 4.5GPT-5.1Result
MMLU-ProXSource 85.7%—Not comparable
NOVA-63Source 56.7%—Not comparable
Multimodal
BenchmarkClaude Opus 4.5GPT-5.1Result
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%75.5%GPT-5.1 leads
Design Arena WebsiteSource 12791220Claude Opus 4.5 leads
Inst. Following
BenchmarkClaude Opus 4.5GPT-5.1Result
IFEvalSource 90.9%—Not comparable
IFBenchSource 58%—Not comparable
AA-IFBenchSource 43.0%72.9%GPT-5.1 leads
Frequently Asked Questions (2)

Which is better, Claude Opus 4.5 or GPT-5.1?

Claude Opus 4.5 is ahead on BenchLM's BenchAlign leaderboard, 64.22 to 53.65. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 20.690% and 31.034%.

Which is better for math, Claude Opus 4.5 or GPT-5.1?

Claude Opus 4.5 has the edge for math in this comparison, averaging 57.5 versus 26.4. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.

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