This handy tool from mapei lets you see what the grout will look like before you actually grout.

It has pre-loaded pics of certain tile types and rooms/floors etc.

just click on the grout colour and it automatically changes in the picture to that colour.

Mapei Fughe Colorate

And you can look at the pdf's for each grout type as well...

handy tool...

Thats a hoot Dave, try the red on all the pics.

Used this before but also have samples from mapei and even then double check with customer by mixing a small bit of grout up and stick it in a couple of offcuts whilst I'm tiling so the customer knows what they are getting!

Thats kinda cool. Would be nice if you could load your own images though.

Brilliant tool Dave!! superb.

Only works if you use grout ( weight ) and water ( volume ) ratio exactly !
Even then I am not convinced !
As I have found to my own cost, showed customer sample of Beige from grout swatches in a box ( SUPPLIED BY MAPEI ) My grout was a shade darker ! Had to spend 3 days with Fein, taking it out as customer did not like it.
Upshot is, I never show samples now
And am moving away from Mapei grout to Granfix.
Still trust Mapei adhesives

I do explain that the samples I have that the colour may vary slightly due to batch numbers

Ive got a swatch from mapei, with all the colours then some tile pics with no grout in, you put the pic over the swatch and it gives you an idea. Comes in handy.

Quite a cool tool that Dave. Will give a basic idea of how things look. Obviously real life it would be slightly different but at least it gives a starting point to discuss with customer.