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BenchLM

Model comparison

Claude Opus 4.8 vs GPT-5.1

Data verified

Head-to-head evidence from 20 shared benchmark results across 7 categories. Overall scores shown here use BenchLM's provisional ranking lane.

85/100
Margin
12.0pts
← winning
GPT-5.1
OpenAI
73/100
1 category wins0 category wins

Verified leaderboard positions: Claude Opus 4.8 #3; GPT-5.1 unranked

Evidence parity. Claude Opus 4.8 and GPT-5.1 share 20 comparable benchmark results. 1 of 8 categories are comparable. 33 results are unique to Claude Opus 4.8; 2 to GPT-5.1.

Updated July 12, 2026
Shared results
20
Claude Opus 4.8 only
33
GPT-5.1 only
2
Comparable categories
1 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. GPT-5.1 only becomes the better choice if you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 20 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 4.8 is clearly ahead on the provisional aggregate, 85 to 73. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Opus 4.8's sharpest advantage is in mathematics, where it averages 53.9 against 26.4. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 31.250% to 12.500%.

Claude Opus 4.8 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. Claude Opus 4.8 gives you the larger context window at 1M, compared with 200K for GPT-5.1.

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 4.8 and GPT-5.1
CategoryClaude Opus 4.8ΔGPT-5.1
MathClaude Opus 4.853.9Margin← 27.5GPT-5.126.4
AgenticClaude Opus 4.880.3MarginNo overlapGPT-5.1Not measured
CodingClaude Opus 4.876.4MarginNo overlapGPT-5.1Not measured
KnowledgeClaude Opus 4.862.7MarginNo overlapGPT-5.1Not measured
MultimodalClaude Opus 4.877.0MarginNo overlapGPT-5.1Not measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · GPT-5.1

  1. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 31.250%B 12.500%
    Winner: Claude Opus 4.8Δ 18.8
    FrontierMath v2 (Tier 4): Claude Opus 4.8 scored 31.250%; GPT-5.1 scored 12.500%. Claude Opus 4.8 wins this benchmark.

  2. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 47.241%B 31.034%
    Winner: Claude Opus 4.8Δ 16.2
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.8 scored 47.241%; GPT-5.1 scored 31.034%. Claude Opus 4.8 wins this benchmark.

Operational comparison

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

MetricClaude Opus 4.8GPT-5.1Comparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputGPT-5.1$1.25 input / $10 outputGPT-5.1 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableGPT-5.1111 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableGPT-5.157.47 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MGPT-5.1200KClaude Opus 4.8 lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkClaude Opus 4.8GPT-5.1Result
Terminal-Bench 2.0Source 74.6%—Not comparable
BrowseCompSource 84.3%—Not comparable
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%—Not comparable
Finance Agent v2Source 53.9%—Not comparable
GDPval-AASource 1600988Claude Opus 4.8 leads
MCP AtlasSource 82.2%—Not comparable
ToolathlonSource 59.9%—Not comparable
Gert LabsSource 72.97%41.24%Claude Opus 4.8 leads
AA Agentic IndexSource 47.2%21.0%Claude Opus 4.8 leads
Tau2-TelecomSource 94.4%81.9%Claude Opus 4.8 leads
GDPval-AASource 55.0%24.4%Claude Opus 4.8 leads
ResearchClawBenchSource 21.1%—Not comparable
OSWorld 2.0Source 20.6%—Not comparable
AA BriefcaseSource 1354—Not comparable
AA AutomationBenchSource 48.5%—Not comparable
AA EnterpriseOps-GymSource 44.0%—Not comparable
AA Harvey LABSource 7.5%—Not comparable
AA Tau3 BankingSource 27.6%—Not comparable
Coding
BenchmarkClaude Opus 4.8GPT-5.1Result
SWE-bench VerifiedSource 88.6%—Not comparable
SWE-bench ProSource 69.2%—Not comparable
SWE MultilingualSource 84.4%—Not comparable
SWE MultimodalSource 38.4%—Not comparable
Terminal-Bench 2.0Source 74.6%—Not comparable
cursorBench31Source 58.4%—Not comparable
cursorBench32Source 62.3%—Not comparable
AA Coding IndexSource 74.3%49.4%Claude Opus 4.8 leads
Terminal-Bench HardSource 58.3%45.5%Claude Opus 4.8 leads
AA-SciCodeSource 53.5%43.3%Claude Opus 4.8 leads
FrontierCodeSource 46.5%—Not comparable
AA Terminal-Bench 2.1Source 84.6%—Not comparable
Vibe Code BenchSource —24.61%Not comparable
Reasoning
BenchmarkClaude Opus 4.8GPT-5.1Result
AA-LCRSource 67.7%75.0%GPT-5.1 leads
CritPtSource 20.9%4.9%Claude Opus 4.8 leads
Knowledge
BenchmarkClaude Opus 4.8GPT-5.1Result
GPQASource 93.6%—Not comparable
GPQA-DSource 93.6%—Not comparable
HLESource 57.9%—Not comparable
HLE w/o toolsSource 49.8%—Not comparable
Artificial Analysis Intelligence IndexSource 55.7%36.9%Claude Opus 4.8 leads
AA-GPQA DiamondSource 92.0%87.3%Claude Opus 4.8 leads
AA-HLESource 45.7%26.5%Claude Opus 4.8 leads
AA-Omniscience IndexSource 27.4%5.6%Claude Opus 4.8 leads
AA-Omniscience AccuracySource 46.6%37.6%Claude Opus 4.8 leads
AA-Omniscience Hallucination RateSource 35.9%51.3%Claude Opus 4.8 leads
MathClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.1Result
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%31.034%Claude Opus 4.8 leads
FrontierMath v2 (Tier 4)Source 31.250%12.500%Claude Opus 4.8 leads
Multilingual
BenchmarkClaude Opus 4.8GPT-5.1Result
INCLUDESource 87.6%—Not comparable
Multimodal
BenchmarkClaude Opus 4.8GPT-5.1Result
OfficeQA ProSource 66.2%—Not comparable
ScreenSpot ProSource 87.9%—Not comparable
CharXivSource 89.9%—Not comparable
CharXiv w/o toolsSource 80.5%—Not comparable
Design Arena WebsiteSource 12811230Claude Opus 4.8 leads
AA-MMMU-ProSource —75.5%Not comparable
Inst. Following
BenchmarkClaude Opus 4.8GPT-5.1Result
AA-IFBenchSource 62.2%72.9%GPT-5.1 leads
Frequently Asked Questions (2)

Which is better, Claude Opus 4.8 or GPT-5.1?

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 73. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 31.250% and 12.500%.

Which is better for math, Claude Opus 4.8 or GPT-5.1?

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 26.4. Inside this category, FrontierMath v2 (Tier 4) is the benchmark that creates the most daylight between them.

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