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BenchLM

Model comparison

Claude 3.5 Sonnet vs Claude Opus 4.8

Data verified

Head-to-head evidence from 4 shared benchmark results across 3 categories. Overall scores shown here use BenchLM's provisional ranking lane.

39/100
Margin
46.0pts
winning →
85/100
0 category wins3 category wins

Verified leaderboard positions: Claude 3.5 Sonnet unranked; Claude Opus 4.8 #3

Evidence parity. Claude 3.5 Sonnet and Claude Opus 4.8 share 4 comparable benchmark results. 3 of 8 categories are comparable. 0 results are unique to Claude 3.5 Sonnet; 49 to Claude Opus 4.8.

Updated July 12, 2026
Shared results
4
Claude 3.5 Sonnet only
0
Claude Opus 4.8 only
49
Comparable categories
3 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Confidence note. This is a partial-evidence comparison with 4 shared benchmark results across 3 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 39. 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 1.6. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 2.069% to 47.241%.

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 3.5 Sonnet. Claude Opus 4.8 is the reasoning model in the pair, while Claude 3.5 Sonnet 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 3.5 Sonnet.

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 3.5 Sonnet and Claude Opus 4.8
CategoryClaude 3.5 SonnetΔClaude Opus 4.8
MathClaude 3.5 Sonnet1.6Margin→ 52.3Claude Opus 4.853.9
CodingClaude 3.5 Sonnet49.0Margin→ 27.4Claude Opus 4.876.4
KnowledgeClaude 3.5 Sonnet59.4Margin→ 3.3Claude Opus 4.862.7
AgenticClaude 3.5 SonnetNot measuredMarginNo overlapClaude Opus 4.880.3
MultimodalClaude 3.5 SonnetNot measuredMarginNo overlapClaude Opus 4.877.0

Decisive benchmark drivers

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

More
A · Claude 3.5 SonnetB · Claude Opus 4.8

  1. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 2.069%B 47.241%
    Winner: Claude Opus 4.8Δ 45.2
    FrontierMath v2 (Tiers 1-3): Claude 3.5 Sonnet scored 2.069%; Claude Opus 4.8 scored 47.241%. Claude Opus 4.8 wins this benchmark.

  2. SWE-bench Verified

    Coding
    Source ↗
    A 49%B 88.6%
    Winner: Claude Opus 4.8Δ 39.6
    SWE-bench Verified: Claude 3.5 Sonnet scored 49%; Claude Opus 4.8 scored 88.6%. Claude Opus 4.8 wins this benchmark.

  3. GPQA

    Knowledge
    Source ↗
    A 59.4%B 93.6%
    Winner: Claude Opus 4.8Δ 34.2
    GPQA: Claude 3.5 Sonnet scored 59.4%; Claude Opus 4.8 scored 93.6%. Claude Opus 4.8 wins this benchmark.

  4. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 0.000%B 31.250%
    Winner: Claude Opus 4.8Δ 31.3
    FrontierMath v2 (Tier 4): Claude 3.5 Sonnet scored 0.000%; Claude Opus 4.8 scored 31.250%. 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 3.5 SonnetClaude Opus 4.8Comparison
Input / output priceUSD per 1M tokensClaude 3.5 Sonnet$3 input / $15 outputClaude Opus 4.8$5 input / $25 outputClaude 3.5 Sonnet has the lower combined listed price.
Generation speedtokens per secondClaude 3.5 SonnetNot availableClaude Opus 4.8Not availableA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude 3.5 SonnetNot availableClaude Opus 4.8Not availableA complete latency comparison is not available.
Context windowmaximum listed tokensClaude 3.5 Sonnet200KClaude Opus 4.81MClaude Opus 4.8 lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
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 —1600Not 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 —1354Not 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
CodingClaude Opus 4.8 wins
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
SWE-bench VerifiedSource 49%88.6%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 3.5 SonnetClaude Opus 4.8Result
AA-LCRSource —67.7%Not comparable
CritPtSource —20.9%Not comparable
KnowledgeClaude Opus 4.8 wins
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
GPQASource 59.4%93.6%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 3.5 SonnetClaude Opus 4.8Result
FrontierMath v2 (Tiers 1-3)Source 2.069%47.241%Claude Opus 4.8 leads
FrontierMath v2 (Tier 4)Source 0.000%31.250%Claude Opus 4.8 leads
USAMO 2026Source —96.7%Not comparable
Multilingual
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
INCLUDESource —87.6%Not comparable
Multimodal
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
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 —1281Not comparable
Inst. Following
BenchmarkClaude 3.5 SonnetClaude Opus 4.8Result
AA-IFBenchSource —62.2%Not comparable
Frequently Asked Questions (4)

Which is better, Claude 3.5 Sonnet or Claude Opus 4.8?

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 39. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 2.069% and 47.241%.

Which is better for knowledge tasks, Claude 3.5 Sonnet or Claude Opus 4.8?

Claude Opus 4.8 has the edge for knowledge tasks in this comparison, averaging 62.7 versus 59.4. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Claude 3.5 Sonnet or Claude Opus 4.8?

Claude Opus 4.8 has the edge for coding in this comparison, averaging 76.4 versus 49. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.

Which is better for math, Claude 3.5 Sonnet or Claude Opus 4.8?

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 1.6. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.

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