Grammarbook.com gave the following rules that will help us learn how to use “different from” and “different than”
(a) Different from is a separating phrase followed by a noun or pronoun.
– Alone, the adjective different is not comparative; it differentiates one thing (noun or pronoun) from another.
My guitar is different from your ukulele.
(b) Different than is a comparative phrase usually followed by a clause.
– The logic here is than typically follows a comparative adjective such as stronger, shorter, or simpler or a comparative phrase such as more colorful or more legible.
John is stronger than Thomas.
Source: Grammar Book
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