Instagram Stories don’t have a fixed size in inches because they are a digital asset and are defined in pixels. The ideal Instagram Story size in pixels is 1080 x 1920.
Story size in inches depends on DPI (dots per inch) and PPI (pixels per inch), and both vary by device. For example, at 72 PPI, an Instagram Story would measure 15 x 26.67 inches, and at 96 PPI, it would measure 11.25 x 20 inches.
Because of this, it’s much better to measure Instagram stories in pixels. Use Quillbot’s free Instagram Story Templates to make sure you’re using the right story size.