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BenchLM

Model comparison

Claude Opus 4.8 vs GPT-5.5 Pro

Data verified

Head-to-head evidence from 6 shared benchmark results across 4 categories. Overall scores shown here use BenchLM's provisional ranking lane.

85/100
Margin
10.0pts
← winning
75/100
2 category wins1 category wins

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

Evidence parity. Claude Opus 4.8 and GPT-5.5 Pro share 6 comparable benchmark results. 3 of 8 categories are comparable. 47 results are unique to Claude Opus 4.8; 1 to GPT-5.5 Pro.

Updated July 12, 2026
Shared results
6
Claude Opus 4.8 only
47
GPT-5.5 Pro only
1
Comparable categories
3 / 8

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

Confidence note. This is a partial-evidence comparison with 6 shared benchmark results across 4 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 4.8 is clearly ahead on the provisional aggregate, 85 to 75. 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 48.1. The single biggest benchmark swing on the page is FrontierMath v2 (Tier 4), 31.250% 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 4.8. That is roughly 7.2x on output cost alone.

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 Pro
CategoryClaude Opus 4.8ΔGPT-5.5 Pro
AgenticClaude Opus 4.880.3Margin→ 9.8GPT-5.5 Pro90.1
MathClaude Opus 4.853.9Margin← 5.8GPT-5.5 Pro48.1
KnowledgeClaude Opus 4.862.7Margin← 5.5GPT-5.5 Pro57.2
CodingClaude Opus 4.876.4MarginNo overlapGPT-5.5 ProNot measured
MultimodalClaude Opus 4.877.0MarginNo overlapGPT-5.5 ProNot measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · GPT-5.5 Pro

  1. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 31.250%B 39.600%
    Winner: GPT-5.5 ProΔ 8.4
    FrontierMath v2 (Tier 4): Claude Opus 4.8 scored 31.250%; GPT-5.5 Pro scored 39.600%. GPT-5.5 Pro wins this benchmark.

  2. BrowseComp

    Agentic
    Source ↗
    A 84.3%B 90.1%
    Winner: GPT-5.5 ProΔ 5.8
    BrowseComp: Claude Opus 4.8 scored 84.3%; GPT-5.5 Pro scored 90.1%. GPT-5.5 Pro wins this benchmark.

  3. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 47.241%B 51.000%
    Winner: GPT-5.5 ProΔ 3.8
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.8 scored 47.241%; GPT-5.5 Pro scored 51.000%. GPT-5.5 Pro wins this benchmark.

  4. HLE

    Knowledge
    Source ↗
    A 57.9%B 57.2%
    Winner: Claude Opus 4.8Δ 0.7
    HLE: Claude Opus 4.8 scored 57.9%; GPT-5.5 Pro scored 57.2%. 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-5.5 ProComparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputGPT-5.5 Pro$30 input / $180 outputClaude Opus 4.8 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableGPT-5.5 ProNot availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableGPT-5.5 ProNot availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MGPT-5.5 Pro1MListed context windows are equal.

Benchmark Deep Dive

AgenticGPT-5.5 Pro wins
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
Terminal-Bench 2.0Source 74.6%—Not comparable
BrowseCompSource 84.3%90.1%GPT-5.5 Pro leads
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%—Not comparable
Finance Agent v2Source 53.9%—Not comparable
GDPval-AASource 1600—Not comparable
MCP AtlasSource 82.2%—Not comparable
ToolathlonSource 59.9%—Not comparable
Gert LabsSource 72.97%—Not comparable
AA Agentic IndexSource 47.2%—Not comparable
Tau2-TelecomSource 94.4%—Not comparable
GDPval-AASource 55.0%—Not comparable
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-5.5 ProResult
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%—Not comparable
Terminal-Bench HardSource 58.3%—Not comparable
AA-SciCodeSource 53.5%—Not comparable
FrontierCodeSource 46.5%—Not comparable
AA Terminal-Bench 2.1Source 84.6%—Not comparable
Reasoning
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
AA-LCRSource 67.7%—Not comparable
CritPtSource 20.9%30.6%GPT-5.5 Pro leads
KnowledgeClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
GPQASource 93.6%—Not comparable
GPQA-DSource 93.6%—Not comparable
HLESource 57.9%57.2%Claude Opus 4.8 leads
HLE w/o toolsSource 49.8%43.1%Claude Opus 4.8 leads
Artificial Analysis Intelligence IndexSource 55.7%—Not comparable
AA-GPQA DiamondSource 92.0%—Not comparable
AA-HLESource 45.7%—Not comparable
AA-Omniscience IndexSource 27.4%—Not comparable
AA-Omniscience AccuracySource 46.6%—Not comparable
AA-Omniscience Hallucination RateSource 35.9%—Not comparable
MathClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%51.000%GPT-5.5 Pro leads
FrontierMath v2 (Tier 4)Source 31.250%39.600%GPT-5.5 Pro leads
FrontierMath (legacy)Source —52.4%Not comparable
Multilingual
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
INCLUDESource 87.6%—Not comparable
Multimodal
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
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 1281—Not comparable
Inst. Following
BenchmarkClaude Opus 4.8GPT-5.5 ProResult
AA-IFBenchSource 62.2%—Not comparable
Frequently Asked Questions (4)

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

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 75. The biggest single separator in this matchup is FrontierMath v2 (Tier 4), where the scores are 31.250% and 39.600%.

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

Claude Opus 4.8 has the edge for knowledge tasks in this comparison, averaging 62.7 versus 57.2. Inside this category, HLE w/o tools is the benchmark that creates the most daylight between them.

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

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 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 4.8 or GPT-5.5 Pro?

GPT-5.5 Pro has the edge for agentic tasks in this comparison, averaging 90.1 versus 80.3. Inside this category, BrowseComp is the benchmark that creates the most daylight between them.

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Last updated: July 12, 2026

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