AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Claude Sonnet 4.5 vs o1-pro

Anthropic
Claude Sonnet 4.5
OpenAI
o1-pro
Overview
CompanyAnthropicOpenAI
Release dateSep 29 2025Mar 19 2025
AccessProprietaryProprietary
Benchmarks
Nonsense detection
BullshitBench v2
79%
Coding
SWE-Bench Verified
77.2%
Next.js coding
Next.js Evals
50%
Science
GPQA Diamond
83.4%
Multimodal
MMMU
68%
Timeline
Release gapo1-pro shipped 194 days before Claude Sonnet 4.5

Which is better: Claude Sonnet 4.5 or o1-pro?

Claude Sonnet 4.5 and o1-pro don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o1-pro shipped 194 days before Claude Sonnet 4.5, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and o1-pro don't publish scores on any of the same benchmarks.

Frequently asked questions

Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.

o1-pro was released by OpenAI on Mar 19 2025.

Other comparisons