Good question, Benedict certainly has sported an array of different shades during his career thus far!

As you probably will have guessed his dark locks as Sherlock have been dyed. He was in fact asked by ESQUIRE magazine back in July 2010 what his natural hair colour was and answered,

“It’s been dyed quite a bit darker. I’m auburn and that’s just not right for Sherlock. He’s a creature of the night. He’s got a dark, sociopathic side to him. The archetypal image of him is that he’s a slick-looking, dark-haired gentleman with aquiline features. The first thing my mum said when I mentioned to her that I’d got the part was “You don’t have the right nose.”“

So naturally he’s more of a red head. Darker than seen in ‘Frankenstein’, as his hair colour in this was a good deal blonder as it was done for ‘War Horse’, due to the fact Spielberg wanted him to go “sandy” for the role.

Benedict’s upcoming film ‘Wreckers’ appears to feature him with his natural colour hair but if you head over to benedictcumberbatch.co.uk the below link is probably a good representation:

http://www.benedictcumberbatch.co.uk/a-taste-of-life-vip-preview/