XL times are representable by fractional days, so multiply the time by
the number of minutes in a day:

A1: 0:03:30
A2: =A1*24*60 === 3.5

when formatted as General or Number. A bit more efficiently:

A2: =A1*1440





In article ,
Martin wrote:

I want change the time in my worksheet.
I need change 3:30 to 3.5 decimals numbers