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BenchLM

Model comparison

Claude Opus 4.8 vs Claude Sonnet 4.5

Data verified

Head-to-head evidence from 8 shared benchmark results across 5 categories. Overall scores shown here use BenchLM's provisional ranking lane.

85/100
Margin
25.0pts
← winning
60/100
2 category wins2 category wins

Verified leaderboard positions: Claude Opus 4.8 #3; Claude Sonnet 4.5 unranked

Evidence parity. Claude Opus 4.8 and Claude Sonnet 4.5 share 8 comparable benchmark results. 4 of 8 categories are comparable. 45 results are unique to Claude Opus 4.8; 4 to Claude Sonnet 4.5.

Updated July 12, 2026
Shared results
8
Claude Opus 4.8 only
45
Claude Sonnet 4.5 only
4
Comparable categories
4 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. Claude Sonnet 4.5 only becomes the better choice if knowledge is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 8 shared benchmark results across 5 evidence categories; 4 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 60. 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 11.2. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 47.241% to 13.495%. Claude Sonnet 4.5 does hit back in knowledge, so the answer changes if that is the part of the workload you care about most.

Claude Opus 4.8 is also the more expensive model on tokens at $5.00 input / $25.00 output per 1M tokens, versus $3.00 input / $15.00 output per 1M tokens for Claude Sonnet 4.5. Claude Opus 4.8 is the reasoning model in the pair, while Claude Sonnet 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. Claude Opus 4.8 gives you the larger context window at 1M, compared with 200K for Claude Sonnet 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 4.8 and Claude Sonnet 4.5
CategoryClaude Opus 4.8ΔClaude Sonnet 4.5
MathClaude Opus 4.853.9Margin← 42.7Claude Sonnet 4.511.2
AgenticClaude Opus 4.880.3Margin← 24.9Claude Sonnet 4.555.4
KnowledgeClaude Opus 4.862.7Margin→ 20.7Claude Sonnet 4.583.4
CodingClaude Opus 4.876.4Margin→ 0.8Claude Sonnet 4.577.2
ReasoningClaude Opus 4.8Not measuredMarginNo overlapClaude Sonnet 4.513.6
MultimodalClaude Opus 4.877.0MarginNo overlapClaude Sonnet 4.5Not measured

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · Claude Sonnet 4.5

  1. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 47.241%B 13.495%
    Winner: Claude Opus 4.8Δ 33.7
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.8 scored 47.241%; Claude Sonnet 4.5 scored 13.495%. Claude Opus 4.8 wins this benchmark.

  2. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 31.250%B 4.167%
    Winner: Claude Opus 4.8Δ 27.1
    FrontierMath v2 (Tier 4): Claude Opus 4.8 scored 31.250%; Claude Sonnet 4.5 scored 4.167%. Claude Opus 4.8 wins this benchmark.

  3. Terminal-Bench 2.0

    Agentic
    Source ↗
    A 74.6%B 50%
    Winner: Claude Opus 4.8Δ 24.6
    Terminal-Bench 2.0: Claude Opus 4.8 scored 74.6%; Claude Sonnet 4.5 scored 50%. Claude Opus 4.8 wins this benchmark.

  4. OSWorld-Verified

    Agentic
    Source ↗
    A 83.4%B 61.4%
    Winner: Claude Opus 4.8Δ 22
    OSWorld-Verified: Claude Opus 4.8 scored 83.4%; Claude Sonnet 4.5 scored 61.4%. Claude Opus 4.8 wins this benchmark.

  5. SWE-bench Verified

    Coding
    Source ↗
    A 88.6%B 77.2%
    Winner: Claude Opus 4.8Δ 11.4
    SWE-bench Verified: Claude Opus 4.8 scored 88.6%; Claude Sonnet 4.5 scored 77.2%. 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 4.8Claude Sonnet 4.5Comparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputClaude Sonnet 4.5$3 input / $15 outputClaude Sonnet 4.5 has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableClaude Sonnet 4.5Not availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableClaude Sonnet 4.5Not availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MClaude Sonnet 4.5200KClaude Opus 4.8 lists the larger context window.

Benchmark Deep Dive

AgenticClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
Terminal-Bench 2.0Source 74.6%50%Claude Opus 4.8 leads
BrowseCompSource 84.3%—Not comparable
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%61.4%Claude Opus 4.8 leads
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%48.51%Claude Opus 4.8 leads
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
VITA-BenchSource —17.0%Not comparable
JobBenchSource —27.7%Not comparable
CodingClaude Sonnet 4.5 wins
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
SWE-bench VerifiedSource 88.6%77.2%Claude Opus 4.8 leads
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 4.8Claude Sonnet 4.5Result
AA-LCRSource 67.7%—Not comparable
CritPtSource 20.9%—Not comparable
ARC-AGI-2Source —13.6%Not comparable
KnowledgeClaude Sonnet 4.5 wins
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
GPQASource 93.6%83.4%Claude Opus 4.8 leads
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%—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 4.8Claude Sonnet 4.5Result
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%13.495%Claude Opus 4.8 leads
FrontierMath v2 (Tier 4)Source 31.250%4.167%Claude Opus 4.8 leads
AIME 2025Source —87%Not comparable
Multilingual
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
INCLUDESource 87.6%—Not comparable
Multimodal
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
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 12811232Claude Opus 4.8 leads
Inst. Following
BenchmarkClaude Opus 4.8Claude Sonnet 4.5Result
AA-IFBenchSource 62.2%—Not comparable
Frequently Asked Questions (5)

Which is better, Claude Opus 4.8 or Claude Sonnet 4.5?

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 60. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 47.241% and 13.495%.

Which is better for knowledge tasks, Claude Opus 4.8 or Claude Sonnet 4.5?

Claude Sonnet 4.5 has the edge for knowledge tasks in this comparison, averaging 83.4 versus 62.7. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Claude Opus 4.8 or Claude Sonnet 4.5?

Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 77.2 versus 76.4. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude Opus 4.8 or Claude Sonnet 4.5?

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 11.2. 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 Claude Sonnet 4.5?

Claude Opus 4.8 has the edge for agentic tasks in this comparison, averaging 80.3 versus 55.4. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

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Last updated: July 12, 2026

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