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BenchLM

Model comparison

Claude Opus 4.8 vs Gemini 3.5 Flash

Data verified

Head-to-head evidence from 40 shared benchmark results across 7 categories. Overall scores shown here use BenchLM's provisional ranking lane.

85/100
Margin
5.0pts
← winning
80/100
4 category wins1 category wins

Verified leaderboard positions: Claude Opus 4.8 #3; Gemini 3.5 Flash #10

Evidence parity. Claude Opus 4.8 and Gemini 3.5 Flash share 40 comparable benchmark results. 5 of 8 categories are comparable. 13 results are unique to Claude Opus 4.8; 11 to Gemini 3.5 Flash.

Updated July 12, 2026
Shared results
40
Claude Opus 4.8 only
13
Gemini 3.5 Flash only
11
Comparable categories
5 / 8

Pick Claude Opus 4.8 if you want the stronger benchmark profile. Gemini 3.5 Flash only becomes the better choice if multimodal & grounded is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 40 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 80. 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 54.6. The single biggest benchmark swing on the page is HLE, 57.9% to 40.2%. Gemini 3.5 Flash does hit back in multimodal & grounded, 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 $1.50 input / $9.00 output per 1M tokens for Gemini 3.5 Flash. That is roughly 2.8x 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 Gemini 3.5 Flash
CategoryClaude Opus 4.8ΔGemini 3.5 Flash
CodingClaude Opus 4.876.4Margin← 21.8Gemini 3.5 Flash54.6
MathClaude Opus 4.853.9Margin← 21.0Gemini 3.5 Flash32.9
KnowledgeClaude Opus 4.862.7Margin← 15.5Gemini 3.5 Flash47.2
MultimodalClaude Opus 4.877.0Margin→ 6.8Gemini 3.5 Flash83.8
AgenticClaude Opus 4.880.3Margin← 3.1Gemini 3.5 Flash77.2
ReasoningClaude Opus 4.8Not measuredMarginNo overlapGemini 3.5 Flash74.7
Inst. FollowingClaude Opus 4.8Not measuredMarginNo overlapGemini 3.5 Flash76.3

Decisive benchmark drivers

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

More
A · Claude Opus 4.8B · Gemini 3.5 Flash

  1. HLE

    Knowledge
    Source ↗
    A 57.9%B 40.2%
    Winner: Claude Opus 4.8Δ 17.7
    HLE: Claude Opus 4.8 scored 57.9%; Gemini 3.5 Flash scored 40.2%. Claude Opus 4.8 wins this benchmark.

  2. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 31.250%B 14.583%
    Winner: Claude Opus 4.8Δ 16.7
    FrontierMath v2 (Tier 4): Claude Opus 4.8 scored 31.250%; Gemini 3.5 Flash scored 14.583%. Claude Opus 4.8 wins this benchmark.

  3. SWE-bench Pro

    Coding
    Source ↗
    A 69.2%B 55.1%
    Winner: Claude Opus 4.8Δ 14.1
    SWE-bench Pro: Claude Opus 4.8 scored 69.2%; Gemini 3.5 Flash scored 55.1%. Claude Opus 4.8 wins this benchmark.

  4. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 47.241%B 38.966%
    Winner: Claude Opus 4.8Δ 8.3
    FrontierMath v2 (Tiers 1-3): Claude Opus 4.8 scored 47.241%; Gemini 3.5 Flash scored 38.966%. Claude Opus 4.8 wins this benchmark.

  5. CharXiv

    Multimodal
    Source ↗
    A 89.9%B 84.2%
    Winner: Claude Opus 4.8Δ 5.7
    CharXiv: Claude Opus 4.8 scored 89.9%; Gemini 3.5 Flash scored 84.2%. 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 4.8Gemini 3.5 FlashComparison
Input / output priceUSD per 1M tokensClaude Opus 4.8$5 input / $25 outputGemini 3.5 Flash$1.5 input / $9 outputGemini 3.5 Flash has the lower combined listed price.
Generation speedtokens per secondClaude Opus 4.8Not availableGemini 3.5 Flash284.2 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Opus 4.8Not availableGemini 3.5 Flash18.55 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Opus 4.81MGemini 3.5 Flash1MListed context windows are equal.

Benchmark Deep Dive

AgenticClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
Terminal-Bench 2.0Source 74.6%76.2%Gemini 3.5 Flash leads
BrowseCompSource 84.3%—Not comparable
DeepSearchQASource 93.1%—Not comparable
OSWorld-VerifiedSource 83.4%78.4%Claude Opus 4.8 leads
Finance Agent v2Source 53.9%57.9%Gemini 3.5 Flash leads
GDPval-AASource 16001349Claude Opus 4.8 leads
MCP AtlasSource 82.2%83.6%Gemini 3.5 Flash leads
ToolathlonSource 59.9%56.5%Claude Opus 4.8 leads
Gert LabsSource 72.97%61.85%Claude Opus 4.8 leads
AA Agentic IndexSource 47.2%37.5%Claude Opus 4.8 leads
Tau2-TelecomSource 94.4%95.3%Gemini 3.5 Flash leads
GDPval-AASource 55.0%42.4%Claude Opus 4.8 leads
ResearchClawBenchSource 21.1%18.0%Claude Opus 4.8 leads
OSWorld 2.0Source 20.6%—Not comparable
AA BriefcaseSource 1354866Claude Opus 4.8 leads
AA AutomationBenchSource 48.5%42.6%Claude Opus 4.8 leads
AA EnterpriseOps-GymSource 44.0%50.1%Gemini 3.5 Flash leads
AA Harvey LABSource 7.5%1.7%Claude Opus 4.8 leads
AA Tau3 BankingSource 27.6%25.4%Claude Opus 4.8 leads
APEX-Agents-AASource —47.1%Not comparable
AA ITBenchSource —40.3%Not comparable
CodingClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
SWE-bench VerifiedSource 88.6%—Not comparable
SWE-bench ProSource 69.2%55.1%Claude Opus 4.8 leads
SWE MultilingualSource 84.4%—Not comparable
SWE MultimodalSource 38.4%—Not comparable
Terminal-Bench 2.0Source 74.6%76.2%Gemini 3.5 Flash leads
cursorBench31Source 58.4%49.8%Claude Opus 4.8 leads
cursorBench32Source 62.3%48.8%Claude Opus 4.8 leads
AA Coding IndexSource 74.3%70.1%Claude Opus 4.8 leads
Terminal-Bench HardSource 58.3%40.9%Claude Opus 4.8 leads
AA-SciCodeSource 53.5%53.1%Claude Opus 4.8 leads
FrontierCodeSource 46.5%—Not comparable
AA Terminal-Bench 2.1Source 84.6%78.7%Claude Opus 4.8 leads
SciCodeSource —53.1%Not comparable
Vibe Code BenchSource —48.68%Not comparable
Reasoning
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
AA-LCRSource 67.7%69.3%Gemini 3.5 Flash leads
CritPtSource 20.9%13.1%Claude Opus 4.8 leads
MRCRv2Source —77.3%Not comparable
MRCR 1MSource —26.6%Not comparable
ARC-AGI-2Source —72.1%Not comparable
KnowledgeClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
GPQASource 93.6%92.2%Claude Opus 4.8 leads
GPQA-DSource 93.6%92.7%Claude Opus 4.8 leads
HLESource 57.9%40.2%Claude Opus 4.8 leads
HLE w/o toolsSource 49.8%—Not comparable
Artificial Analysis Intelligence IndexSource 55.7%50.2%Claude Opus 4.8 leads
AA-GPQA DiamondSource 92.0%92.2%Gemini 3.5 Flash leads
AA-HLESource 45.7%41.0%Claude Opus 4.8 leads
AA-Omniscience IndexSource 27.4%22.7%Claude Opus 4.8 leads
AA-Omniscience AccuracySource 46.6%51.9%Gemini 3.5 Flash leads
AA-Omniscience Hallucination RateSource 35.9%60.7%Claude Opus 4.8 leads
MathClaude Opus 4.8 wins
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
USAMO 2026Source 96.7%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 47.241%38.966%Claude Opus 4.8 leads
FrontierMath v2 (Tier 4)Source 31.250%14.583%Claude Opus 4.8 leads
Multilingual
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
INCLUDESource 87.6%—Not comparable
MultimodalGemini 3.5 Flash wins
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
OfficeQA ProSource 66.2%—Not comparable
ScreenSpot ProSource 87.9%—Not comparable
CharXivSource 89.9%84.2%Claude Opus 4.8 leads
CharXiv w/o toolsSource 80.5%—Not comparable
Design Arena WebsiteSource 12811299Gemini 3.5 Flash leads
MMMU-ProSource —83.6%Not comparable
Blueprint-Bench 2Source —33.6%Not comparable
AA-MMMU-ProSource —84.3%Not comparable
Inst. Following
BenchmarkClaude Opus 4.8Gemini 3.5 FlashResult
AA-IFBenchSource 62.2%76.3%Gemini 3.5 Flash leads
IFBenchSource —76.3%Not comparable
Frequently Asked Questions (6)

Which is better, Claude Opus 4.8 or Gemini 3.5 Flash?

Claude Opus 4.8 is ahead on BenchLM's provisional leaderboard, 85 to 80. The biggest single separator in this matchup is HLE, where the scores are 57.9% and 40.2%.

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

Claude Opus 4.8 has the edge for knowledge tasks in this comparison, averaging 62.7 versus 47.2. 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 Gemini 3.5 Flash?

Claude Opus 4.8 has the edge for coding in this comparison, averaging 76.4 versus 54.6. Inside this category, Terminal-Bench Hard is the benchmark that creates the most daylight between them.

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

Claude Opus 4.8 has the edge for math in this comparison, averaging 53.9 versus 32.9. 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 Gemini 3.5 Flash?

Claude Opus 4.8 has the edge for agentic tasks in this comparison, averaging 80.3 versus 77.2. 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 Gemini 3.5 Flash?

Gemini 3.5 Flash has the edge for multimodal and grounded tasks in this comparison, averaging 83.8 versus 77. Inside this category, Design Arena Website is the benchmark that creates the most daylight between them.

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