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GPT-5.5-Pro vs o1

OpenAI GPT-5.5-Pro vs OpenAI o1 — side-by-side specs.

OpenAI
GPT-5.5-Pro
OpenAI
o1
Overview
CompanyOpenAIOpenAI
Release dateApr 23 2026Dec 5 2024
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Web browsing
BrowseComp
90.1%
Advanced math
FrontierMath · Tier 1–3
52.4%
Advanced math
FrontierMath · Tier 4
39.6%
Knowledge work
GDPval (win/tie rate)
82.3%
Timeline
Release gapo1 shipped 504 days before GPT-5.5-Pro

Which is better: GPT-5.5-Pro or o1?

GPT-5.5-Pro and o1 don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o1 shipped 504 days before GPT-5.5-Pro, 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 — GPT-5.5-Pro and o1 don't publish scores on any of the same benchmarks.

Frequently asked questions

When was GPT-5.5-Pro released?
GPT-5.5-Pro was released by OpenAI on Apr 23 2026.
When was o1 released?
o1 was released by OpenAI on Dec 5 2024.

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