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Model comparison

Claude Sonnet 4.5 vs o3

Data verified

Head-to-head evidence from 3 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

53.61/100
Margin
5.7pts
← winning
o3
OpenAI
47.89/100
0 category wins1 category wins

Public leaderboard positions: Claude Sonnet 4.5 #96 (Estimated); o3 #131 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Sonnet 4.5 and o3 share 3 comparable benchmark results. 1 of 8 categories are comparable. 9 results are unique to Claude Sonnet 4.5; 13 to o3.

Updated July 22, 2026
Shared results
3
Claude Sonnet 4.5 only
9
o3 only
13
Comparable categories
1 / 8

Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. o3 only becomes the better choice if mathematics is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 3 shared benchmark results across 2 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Sonnet 4.5 is clearly ahead on the BenchAlign aggregate, 53.61 to 47.89. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for o3. o3 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.

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 Sonnet 4.5 and o3
CategoryClaude Sonnet 4.5Δo3
MathClaude Sonnet 4.511.2Margin→ 3.3o314.5
AgenticClaude Sonnet 4.555.4MarginNo overlapo3Not measured
CodingClaude Sonnet 4.577.2MarginNo overlapo3Not measured
ReasoningClaude Sonnet 4.513.6MarginNo overlapo3Not measured
KnowledgeClaude Sonnet 4.583.4MarginNo overlapo3Not measured

Decisive benchmark drivers

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

More
A · Claude Sonnet 4.5B · o3

  1. FrontierMath v2 (Tiers 1-3)

    Math
    Source ↗
    A 13.495%B 18.685%
    Winner: o3Δ 5.2
    FrontierMath v2 (Tiers 1-3): Claude Sonnet 4.5 scored 13.495%; o3 scored 18.685%. o3 wins this benchmark.

  2. FrontierMath v2 (Tier 4)

    Math
    Source ↗
    A 4.167%B 2.083%
    Winner: Claude Sonnet 4.5Δ 2.1
    FrontierMath v2 (Tier 4): Claude Sonnet 4.5 scored 4.167%; o3 scored 2.083%. Claude Sonnet 4.5 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricClaude Sonnet 4.5o3Comparison
Input / output priceUSD per 1M tokensClaude Sonnet 4.5$3 input / $15 outputo3$2 input / $8 outputo3 has the lower combined listed price.
Generation speedtokens per secondClaude Sonnet 4.5Not availableo3118 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Sonnet 4.5Not availableo35.38 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Sonnet 4.5200Ko3200KListed context windows are equal.

Benchmark Deep Dive

Agentic
BenchmarkClaude Sonnet 4.5o3Result
Terminal-Bench 2.0Source 50%—Not comparable
OSWorld-VerifiedSource 61.4%—Not comparable
VITA-BenchSource 17.0%—Not comparable
Gert LabsSource 48.51%—Not comparable
JobBenchSource 27.7%—Not comparable
τ²-bench resultsSource —80.7%Not comparable
Coding
BenchmarkClaude Sonnet 4.5o3Result
SWE-bench VerifiedSource 77.2%—Not comparable
AA-SciCodeSource —41.0%Not comparable
Reasoning
BenchmarkClaude Sonnet 4.5o3Result
ARC-AGI-2Source 13.6%—Not comparable
AA-LCRSource —69.3%Not comparable
CritPtSource —1.1%Not comparable
Knowledge
BenchmarkClaude Sonnet 4.5o3Result
GPQASource 83.4%—Not comparable
Artificial Analysis Intelligence IndexSource —30.4%Not comparable
AA-GPQA DiamondSource —82.7%Not comparable
AA-HLESource —20.0%Not comparable
AA-Omniscience IndexSource —-15.3%Not comparable
AA-Omniscience AccuracySource —38.4%Not comparable
AA-Omniscience Hallucination RateSource —87.1%Not comparable
Matho3 wins
BenchmarkClaude Sonnet 4.5o3Result
AIME 2025Source 87%—Not comparable
FrontierMath v2 (Tiers 1-3)Source 13.495%18.685%o3 leads
FrontierMath v2 (Tier 4)Source 4.167%2.083%Claude Sonnet 4.5 leads
AA MATH-500Source —99.2%Not comparable
Multimodal
BenchmarkClaude Sonnet 4.5o3Result
Design Arena WebsiteSource 12191067Claude Sonnet 4.5 leads
AA-MMMU-ProSource —70.1%Not comparable
Inst. Following
BenchmarkClaude Sonnet 4.5o3Result
AA-IFBenchSource —71.4%Not comparable
Frequently Asked Questions (2)

Which is better, Claude Sonnet 4.5 or o3?

Claude Sonnet 4.5 is ahead on BenchLM's BenchAlign leaderboard, 53.61 to 47.89. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 13.495% and 18.685%.

Which is better for math, Claude Sonnet 4.5 or o3?

o3 has the edge for math in this comparison, averaging 14.5 versus 11.2. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.

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