Typically around 200 calories + your chosen mixer, we recommend 200-250ml milk/ nut milk. 

Here are the typical number of calories in 100ml of:

Whole milk: 65
Semi-skimmed milk: 45

Koko Dairy Free Unsweetened Coconut milk: 15
Koko Dairy Free Original Coconut milk: 27

Plenish Hazelnut: 29
Plenish Almond: 34
Plenish Oat: 41
Plenish Coconut: 46
Plenish Cashew: 34

Alpro Almond Original: 22
Alpro Almond Un-roasted No Sugars: 13
Alpro Almond Roasted No Sugars: 13
Alpro Soya Original: 42
Alpro Soya Light: 28

Hope this helps!