An embroidery machine comes with at least one hoop, if not several. Hoops are commonly referred to as 4″ x 4″, 5″ x 7″, and so on. That measurement refers to the size of the sewing field and not the actual size of the hoop. Every embroidery machine has a sewing field limit that will be noted in the machine manual. Single-needle machines recognize the hoop that is attached and will not allow you to stitch a design that is larger than the attached hoop; it also won’t stitch if the design has been moved out of the sewing field.
It gets a bit more complicated than that. A 4″ x 4″ hoop does not actually stitch a sewing field of 4″ x 4″; rather it fills a sewing field of 100mm x 100mm. Since the metric system does not convert evenly to imperial, the embroidery industry has taken the liberty of rounding off the numbers in inches. So what to do? Read your manual, learn the true size of your sewing field, and make the best of it! As well we have also created this pdf which provides the interior measurements of all our hoops.
As a rule, it’s best to use the smallest hoop available for the design. That means if your design measures 3″ x 2″, a 4″ x 4″ will provide the best stabilization on the fabric for that design. It doesn’t mean you can’t use a 5″ x 7″ hoop; it means the fabric will be held tighter in a 4″ x 4″ hoop. There may be several reasons why you would opt to use a larger-than-necessary hoop for a design: you’re adding more than one design, a garment detail (such as a button, pocket flap or rivet) may obstruct a 4″ x 4″ frame, or you’re struggling to hoop absolutely square for a design that almost fills the frame.