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

Home/Compare/Claude 2.1 vs o3

Claude 2.1 vs o3

Anthropic Claude 2.1 vs OpenAI o3 — side-by-side specs.

Anthropic
Claude 2.1
OpenAI
o3
Overview
CompanyAnthropicOpenAI
Release dateNov 21 2023Apr 16 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Timeline
Release gapClaude 2.1 shipped 512 days before o3

Which is better: Claude 2.1 or o3?

Claude 2.1 and o3 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude 2.1 shipped 512 days before o3, 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 2.1 and o3 don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Claude 2.1 released?
Claude 2.1 was released by Anthropic on Nov 21 2023.
When was o3 released?
o3 was released by OpenAI on Apr 16 2025.

Other comparisons