Which is better, Claude Sonnet 4 or Claude Sonnet 4.5?

Across 59 shared benchmarks tracked on Vector Wire, Claude Sonnet 4 leads on 9 and Claude Sonnet 4.5 leads on 47 — Claude Sonnet 4.5 leads on more. Strengths differ by axis; the table below shows every head-to-head number with provenance.

SEEDRefresh Models —Deals —Regulatory —Sources —

Claude Sonnet 4 vs Claude Sonnet 4.5

AnthropicvsAnthropic59 shared benchmarks9–47 head-to-head

Benchmark	Claude Sonnet 4	Claude Sonnet 4.5
AA Agentic Index	39.2	50.6
AA Intelligence	29.8	37.4
AA-LCR	69.7	68.3
AA-Omniscience	0.2	-0.1
AIME 2025	74	88
AIR-Bench 2024	88.3	89.8
arc_agi_1	63.7	63.7
ARC-AGI-2	13.6	13.6
ArtifactsBench	57.3	61.5
Artificial Analysis Coding Index	37.6	52.1
browsecomp	12.2	24.1
browsecomp_zh	29.1	42.4
critpt	1.1	1.1
FinSearchComp-global	42	60.8
Fortress	24.4	17
frontiermath_tier_4	0	4.2
GAIA (text only)	68.3	71.2
gdpval	31.2	40.4
GPQA Diamond	78	83.4
HLE	10.7	19.8
HLE (with tools)	20.3	32
HMMT 2025	15.9	74.6
IFBench	55	57.3
LiveCodeBench	68.5	71
LiveCodeBench v6	48.5	64
mmlu_redux	93.6	95.6
MMLU-Pro	84	88.2
mmmlu	86.5	89.1
MMMU	74.4	79.6
MMMU-Pro	62.4	68.7
Multi-SWE-Bench	35.7	44.3
multichallenge	57.1	55.3
MultiNRC	18.4	35.8
OmniScience Accuracy	22.7	32.9
OmniScience Non-Hallucination	70.9	50.9
OSWorld-Verified	42.2	61.4
scicode	40	45
SEAL VISTA	45.5	48.8
simplebench	45.5	54.3
swe_bench_bash	64.9	71.4
SWE-bench Multilingual	56.9	68
SWE-bench Pro	42.7	43.6
SWE-bench Verified	80.2	82
TAU-bench (airline)	60	70
TAU-bench (retail)	80.5	86.2
TauBench V3 - Banking	16.7	24.5
Terminal-Bench	36.4	51
Terminal-Bench 2.1	36.3	55.8
Terminal-Bench Hard	31.1	35.6
theagentcompany	37	41
vectara_answer_rate	98.6	95.6
vectara_avg_summary_length	145.8	127.8
vectara_factual_consistency	89.7	88
vectara_hallucination_rate ↓	10.3	12
VisualToolBench	4.5	6.2
xbench_deepsearch	64.6	66
τ²-Bench	65	98
τ²-Bench Telecom (AA run)	64.6	78.1
τ³-Bench	13.8	19

Best tracked score per model per benchmark (default configuration; source-attributed). ↓ marks lower-is-better metrics. Open either model for its full surface, provenance and pricing.