For your information: The sizes can vary depending on the label.
How do I find out the right shoe size?
You can also measure your shoe size quickly and easily at home. Just place yourself barefoot on a sufficiently large piece of paper. Use a pencil to draw a line in front of the big toe and behind the heel. Then use a measuring tape or ruler to measure the distance between the two lines and read your shoe size in the table.
Please note the following: Your measurement results in a foot length of 25.3 cm? According to the table, you need the EU shoe size 39 for 25.1 cm and the shoe size 40 for 25.6 cm. Because 25.3 cm is closer to 25.1 cm than to 25.6 cm, in this case order shoe size 39.