LIVE INTELLIGENCE · part of the Xentir AI Index

Claude Sonnet 4 vs Gemini 2.5 Flash (Preview 05 20)

Claude Sonnet 4 · Anthropic, released 2025-05-22
Gemini 2.5 Flash (Preview 05 20) · Google DeepMind, released 2025-05-20

“Epoch AI, 'AI Benchmarking Hub'. Published online at epoch.ai. Retrieved from 'https://epoch.ai/benchmarks' [online resource].” · epoch.ai/benchmarks · Licensed CC BY 4.0 · data last verified 2026-07-26 · Methodology · Data Sources

Head-to-head

Measured on 2 of 9 tracked benchmarks for both models — Claude Sonnet 4 leads on 1, Gemini 2.5 Flash (Preview 05 20) leads on 1.

Benchmark	Claude Sonnet 4	Gemini 2.5 Flash (Preview 05 20)	Leads
Epoch Capabilities Index (ECI)	142.2	142.2	Gemini 2.5 Flash (Preview 05 20)
SWE-bench Verified	Not measured	Not measured	Not measured on both
GPQA Diamond	0.783 (32k)	Not measured	Not measured on both
MATH Level 5	0.844	Not measured	Not measured on both
OTIS Mock AIME 2024-2025	0.711 (32k)	0.708	Claude Sonnet 4
FrontierMath	0.041	Not measured	Not measured on both
FrontierMath Tier 4	0.000	Not measured	Not measured on both
SimpleQA Verified	Not measured	Not measured	Not measured on both
Chess Puzzles	Not measured	Not measured	Not measured on both

Benchmark results measure specific tasks and should not be treated as a universal measure of model quality. A model with no row here for a benchmark has not been measured on it — that is left blank, never estimated.

Full profiles

Claude Sonnet 4 → · Gemini 2.5 Flash (Preview 05 20) → · the full AI Model Rankings table