Matching your hair colour up with boxed hair dye?

if i dye my bleach blonde hair extensions a shade of dark blonde, and take them into the hairdresser, will they be able to match my hair with that colour (my hair is dark brown)?

Or is it easier to have them dye my hair, then try and find a boxed dye off the shelf to match?

thanks :)

Matching your hair colour up with boxed hair dye?

A colorist will take into account your natural hair color and tones when developing a color to match your extensions. The colors in the boxes are only available as is... I'd color the extensions and head to the colorist to get a decent match.