Depends on the fabric. Does it have any stretch? I like a skirt with a tight waistband, so I probably have anything from -0.5cm to 2cm ease. I would suggest you take a skirt that fits well and measure the waistband on that. If you will wear it with flats or heels, I would suggest almost on the floor (1cm from the floor?) in flats, so that it is still long with heels.