"Up to a factor" (traduction) "Ã un facteur

[Th.V]

Hello,

I am looking for the translation of the french expression (usual in Mathematics):

"à un facteur près"

or for a similar type of sentence:

"à un isomorphism près"

Maybe translation is:

"apart from a factor" or "except for a factor" or "up to a factor"

"apart from an isomorphism" or "except for an isomorphism" or "up to an isomorphism".

I am looking for the most pertinent translation and a native english person knowing also mathematics could help me.
Thank you so much for your help.
Kind regards. Th.

[Th.V]

I got some helps and the best translation seems to be "Up to ...."
Th.