At Lilly + Sid all our garments are made with comfort for kids in mind. We work with the British Standard Measurement Guide to ensure size suitability by age from sizes 0-3 months up to 7-8 years. Our sizes fit true to size however if you are in between sizes we do recommend to size up to get the most wear from the garment.
If you have any questions regarding sizing at all please contact us via our social pages or email. Feel free to take a look at our customer reviews page too for customer sizing recommendations!