It depends on many things, but also are within these guidelines. A splash back provides a surface which is to be impervious to water, therefore not allow water to absorb, and depending on your state, the regulations directly behind a water point including a tap or outlet is to be minimum 200mm high, and for heat and fire ratings, the area behind a cooktop needs to be 600mm minimum from your bench top is you have an electric cooktop, and 650mm for gas, with the splash back to extend 200mm either side of the heat source either side. So even if you want to only do this, there will need to be quite a bit of splash back, and often people use things like the bench top, window position and overhead cupboards to contain the splash back, providing you a rough idea of where to start and end one. Although not technically required, even in areas without services, a splash back that changes height and doesn't continue around walls to neatly finish off the surface will look out of place, so for consistency, the splash back is best used to effect, and provides an opportunity to incorporate a colour or interesting surface to the kitchen. By no means should a splash back be an after thought or put in simply in response to the minimum regulations. If you have a layout of your kitchen, start where your overhead cupboards are and draw a line around the entire room (even through windows and openings) to see it complete each wall that is part of the kitchen. Meaning any wall that has a bench top attached. Tis is a good place to start. Hope this helps.

Hi Hu, I love the window in your kitchen, if you go white subway tiles a stack pattern would add a contemporary look and white grout would give a clean and stylish look and blend beautifully with any decor items you add.

Rose213, your 3D picture is showing a much smaller tile than you have mentioned. they appear as maybe a 75 X 150mm tile, which is your traditional subway size. from the choices given, I would choose the 75x300 tile in gloss. The light will bounce off the tiles and be a feature.

Agree with Kate. The lighter colour in your bench would be a good colour for a glass splash back. Your bench top is wayyyy too busy, for any tile. Something simple would be my choice. I have included a colour chart and photo of the splash back colour that I think would work.