Pillowcase without zips or buttons
I used cotton fabric for this one.
I hope you can understand my explanations. I think they make it much more complicated than it really is.
At first you need to decide how big your pillowcase should be depending on the size of your pillow. In my example the pillow has a size of 40 cm (A) x 40 cm (B). Now you put the measurements of your pillow into the equation.
A x 2,5 + 4 cm = The length that your piece of fabric should have.
B + 4cm = The width that your piece of fabric should have.
In my example this means:
40 x 2,5 + 4 = 104 cm = The length.
40 + 4 = 44 cm = The width.
Next you have to fold the yellow section so it is above the light blue section and afterwards you do the same with the red section. The right sides should be inside of the packet.
Then you sew the sides 3 and 4.
You only need to turn it around and fill it with some old pillow and you're done!