Oilily sizes vary from UK standard sizing so if you are not familiar with the brand, you should email the seller to get the measurements of the actual garment

Size     UK              Oilily

2 - 3    98cm           92cm

3 - 4    104cm         98cm

4 - 5    110cm         104cm AND 110cm (see note below)

5 - 6    116cm         116cm

6 years plus, sizing is the same for UK and Oilily

Oilily do tops in 104 and then 116.  They don't make tops in a 110cm size

Skirts, trousers and dresses are made in a 110cm size