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Kimi K2.5 vs o3

2 vs 0 benchmarks won

Moonshot AI
Kimi K2.5
OpenAI
o3
Overview
CompanyMoonshot AIOpenAI
Release dateJan 27 2026Apr 16 2025
Model type
Open sourceYesNo
Specifications
Parameters
1T
Context window
256k
Benchmarks
Science reasoning
GPQA Diamond
87.6%
Software engineering
SWE-Bench Verified
76.8%
Multimodal understanding
MMMU
Timeline
Release gapo3 shipped 286 days before Kimi K2.5

Which is better: Kimi K2.5 or o3?

Kimi K2.5 leads o3 on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). o3 shipped 286 days before Kimi K2.5, so benchmark comparisons should account for the intervening progress.

Kimi K2.5 is an open-source / open-weight model; o3 is proprietary.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Kimi K2.5 released?
Kimi K2.5 was released by Moonshot AI on Jan 27 2026.
When was o3 released?
o3 was released by OpenAI on Apr 16 2025.
Is Kimi K2.5 or o3 open source?
Kimi K2.5 is an open-source / open-weight model released by Moonshot AI. o3 is a proprietary model released by OpenAI.

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