This is Chinese Size,the standard was based on “Foot Length”,not “Shoes Length”, not “Insole Length”.
If you measure Shoes Length, you will order wrong size.
If you measure Insole Length, you will order wrong size.
Size 38 fit for Foot Length 24 centimetre.
Size 39 fit for Foot Length 24.5 centimetre.
Size 40 fit for Foot Length 25 centimetre.
Size 41 fit for Foot Length 25.5 centimetre.
Size 42 fit for Foot Length 26 centimetre.
Size 43 fit for Foot Length 26.5 centimetre.
Size 44 fit for Foot Length 27 centimetre.