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BenchLM

Model comparison

Claude Opus 4.8 vs GPT-5.5

Data verified

Head-to-head evidence from 43 shared benchmark results across 7 categories. Overall scores shown here use BenchLM's provisional ranking lane.

85/100
Margin
7.0pts
← winning
GPT-5.5
OpenAI
78/100
4 category wins1 category wins

Verified leaderboard positions: Claude Opus 4.8 #3; GPT-5.5 #6

Evidence parity. Claude Opus 4.8 and GPT-5.5 share 43 comparable benchmark results. 5 of 8 categories are comparable. 10 results are unique to Claude Opus 4.8; 14 to GPT-5.5.

Updated July 12, 2026
Shared results
43
Claude Opus 4.8 only
10
GPT-5.5 only
14
Comparable categories
5 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. GPT-5.5 only becomes the better choice if agentic is the priority.

Confidence note. This is a partial-evidence comparison with 43 shared benchmark results across 7 evidence categories; 5 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 78. 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 coding, where it averages 76.4 against 58.6. The single biggest benchmark swing on the page is OfficeQA Pro, 66.2% to 54.1%. GPT-5.5 does hit back in agentic, so the answer changes if that is the part of the workload you care about most.

GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.8.

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-5.5
CategoryClaude Opus 4.8ΔGPT-5.5
CodingClaude Opus 4.876.4Margin← 17.8GPT-5.558.6
MultimodalClaude Opus 4.877.0Margin← 6.6GPT-5.570.4
MathClaude Opus 4.853.9Margin← 6.3GPT-5.547.6
KnowledgeClaude Opus 4.862.7Margin← 4.9GPT-5.557.8
AgenticClaude Opus 4.880.3Margin→ 1.3GPT-5.581.6
ReasoningClaude Opus 4.8Not measuredMarginNo overlapGPT-5.585.0

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · GPT-5.5

  1. OfficeQA Pro

    Multimodal
    Source ↗
    A 66.2%B 54.1%
    Winner: Claude Opus 4.8Δ 12.1
    OfficeQA Pro: Claude Opus 4.8 scored 66.2%; GPT-5.5 scored 54.1%. Claude Opus 4.8 wins this benchmark.

  2. SWE-bench Pro

    Coding
    Source ↗
    A 69.2%B 58.6%
    Winner: Claude Opus 4.8Δ 10.6
    SWE-bench Pro: Claude Opus 4.8 scored 69.2%; GPT-5.5 scored 58.6%. Claude Opus 4.8 wins this benchmark.

  3. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 74.6%B 82%
    Winner: GPT-5.5Δ 7.4
    Terminal-Bench 2.0: Claude Opus 4.8 scored 74.6%; GPT-5.5 scored 82%. GPT-5.5 wins this benchmark.

  4. HLE

    Knowledge
    Source ↗
    A 57.9%B 52.2%
    Winner: Claude Opus 4.8Δ 5.7
    HLE: Claude Opus 4.8 scored 57.9%; GPT-5.5 scored 52.2%. Claude Opus 4.8 wins this benchmark.

  5. OSWorld-Verified

    Agentic
    Source ↗
    A 83.4%B 78.7%
    Winner: Claude Opus 4.8Δ 4.7
    OSWorld-Verified: Claude Opus 4.8 scored 83.4%; GPT-5.5 scored 78.7%. 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-5.5Comparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputGPT-5.5$5 input / $30 outputClaude Opus 4.8 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableGPT-5.5Not availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableGPT-5.5Not availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MGPT-5.51MListed context windows are equal.

Benchmark Deep Dive

AgenticGPT-5.5 wins
BenchmarkClaude Opus 4.8GPT-5.5Result
Terminal-Bench 2.0Source 74.6%82%GPT-5.5 leads
BrowseCompSource 84.3%84.4%GPT-5.5 leads
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%78.7%Claude Opus 4.8 leads
Finance Agent v2Source 53.9%—Not comparable
GDPval-AASource 16001494Claude Opus 4.8 leads
MCP AtlasSource 82.2%75.3%Claude Opus 4.8 leads
ToolathlonSource 59.9%55.6%Claude Opus 4.8 leads
Gert LabsSource 72.97%72.93%Claude Opus 4.8 leads
AA Agentic IndexSource 47.2%44.9%Claude Opus 4.8 leads
Tau2-TelecomSource 94.4%93.9%Claude Opus 4.8 leads
GDPval-AASource 55.0%49.7%Claude Opus 4.8 leads
ResearchClawBenchSource 21.1%17.0%Claude Opus 4.8 leads
OSWorld 2.0Source 20.6%13.0%Claude Opus 4.8 leads
AA BriefcaseSource 13541158Claude Opus 4.8 leads
AA AutomationBenchSource 48.5%42.1%Claude Opus 4.8 leads
AA EnterpriseOps-GymSource 44.0%46.6%GPT-5.5 leads
AA Harvey LABSource 7.5%4.2%Claude Opus 4.8 leads
AA Tau3 BankingSource 27.6%31.3%GPT-5.5 leads
CyberGymSource —81.8%Not comparable
APEX-Agents-AASource —37.7%Not comparable
JobBenchSource —42.7%Not comparable
ExploitGymSource —13.4%Not comparable
AA ITBenchSource —45.8%Not comparable
CodingClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5Result
SWE-bench VerifiedSource 88.6%—Not comparable
SWE-bench ProSource 69.2%58.6%Claude Opus 4.8 leads
SWE MultilingualSource 84.4%—Not comparable
SWE MultimodalSource 38.4%—Not comparable
Terminal-Bench 2.0Source 74.6%82.0%GPT-5.5 leads
cursorBench31Source 58.4%59.2%GPT-5.5 leads
cursorBench32Source 62.3%58.4%Claude Opus 4.8 leads
AA Coding IndexSource 74.3%74.9%GPT-5.5 leads
Terminal-Bench HardSource 58.3%60.6%GPT-5.5 leads
AA-SciCodeSource 53.5%56.1%GPT-5.5 leads
FrontierCodeSource 46.5%43.0%Claude Opus 4.8 leads
AA Terminal-Bench 2.1Source 84.6%84.3%Claude Opus 4.8 leads
Vibe Code BenchSource —69.85%Not comparable
React Native EvalsSource —84.7%Not comparable
Reasoning
BenchmarkClaude Opus 4.8GPT-5.5Result
AA-LCRSource 67.7%74.3%GPT-5.5 leads
CritPtSource 20.9%27.1%GPT-5.5 leads
MRCR v2 64K-128KSource —83.1%Not comparable
MRCR v2 128K-256KSource —87.5%Not comparable
ARC-AGI-2Source —85%Not comparable
KnowledgeClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5Result
GPQASource 93.6%93.6%Tie
GPQA-DSource 93.6%93.6%Tie
HLESource 57.9%52.2%Claude Opus 4.8 leads
HLE w/o toolsSource 49.8%41.4%Claude Opus 4.8 leads
Artificial Analysis Intelligence IndexSource 55.7%54.8%Claude Opus 4.8 leads
AA-GPQA DiamondSource 92.0%93.5%GPT-5.5 leads
AA-HLESource 45.7%44.3%Claude Opus 4.8 leads
AA-Omniscience IndexSource 27.4%20.1%Claude Opus 4.8 leads
AA-Omniscience AccuracySource 46.6%56.9%GPT-5.5 leads
AA-Omniscience Hallucination RateSource 35.9%85.5%Claude Opus 4.8 leads
MathClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5Result
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%51.700%GPT-5.5 leads
FrontierMath v2 (Tier 4)Source 31.250%35.400%GPT-5.5 leads
FrontierMath (legacy)Source —51.7%Not comparable
Multilingual
BenchmarkClaude Opus 4.8GPT-5.5Result
INCLUDESource 87.6%—Not comparable
MultimodalClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5Result
OfficeQA ProSource 66.2%54.1%Claude Opus 4.8 leads
ScreenSpot ProSource 87.9%—Not comparable
CharXivSource 89.9%—Not comparable
CharXiv w/o toolsSource 80.5%—Not comparable
Design Arena WebsiteSource 12811290GPT-5.5 leads
MMMU-ProSource —81.2%Not comparable
MMMU-Pro w/ PythonSource —83.2%Not comparable
AA-MMMU-ProSource —79.9%Not comparable
Inst. Following
BenchmarkClaude Opus 4.8GPT-5.5Result
AA-IFBenchSource 62.2%75.9%GPT-5.5 leads
Frequently Asked Questions (6)

Which is better, Claude Opus 4.8 or GPT-5.5?

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 78. The biggest single separator in this matchup is OfficeQA Pro, where the scores are 66.2% and 54.1%.

Which is better for knowledge tasks, Claude Opus 4.8 or GPT-5.5?

Claude Opus 4.8 has the edge for knowledge tasks in this comparison, averaging 62.7 versus 57.8. Inside this category, AA-Omniscience Hallucination Rate is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Opus 4.8 or GPT-5.5?

Claude Opus 4.8 has the edge for coding in this comparison, averaging 76.4 versus 58.6. Inside this category, SWE-bench Pro is the benchmark that creates the most daylight between them.

Which is better for math, Claude Opus 4.8 or GPT-5.5?

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 47.6. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Claude Opus 4.8 or GPT-5.5?

GPT-5.5 has the edge for agentic tasks in this comparison, averaging 81.6 versus 80.3. Inside this category, AA Briefcase is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Claude Opus 4.8 or GPT-5.5?

Claude Opus 4.8 has the edge for multimodal and grounded tasks in this comparison, averaging 77 versus 70.4. Inside this category, OfficeQA Pro is the benchmark that creates the most daylight between them.

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Last updated: July 12, 2026

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