How to find your face shape
Nearly every piece of makeup advice starts with the same phrase: it depends on your face shape. Which is useless until someone tells you how to find it. Here is the honest version, no measuring tape required.
The mirror method
Pull your hair fully back and stand in front of a mirror in even, daylight if possible. Look straight ahead and ask three questions.
One: what is the widest part of my face? Forehead, cheekbones, or jaw. Two: how does my jaw end, rounded, pointed, or square? Three: is my face noticeably longer than it is wide, or close to equal?
Reading the answers
Widest at the cheekbones with a soft, tapered jaw and a face gently longer than wide: oval. Similar but with a rounded hairline and rounded jaw: round, especially if length and width are close.
Widest at the forehead narrowing to a pointed chin: heart. Widest at the jaw with a strong square angle: square or triangle. Forehead, cheekbones and jaw all about the same width with a long face: oblong. Narrow forehead and chin with dramatic cheekbones: diamond.
Why it matters for makeup
Every placement rule in makeup is an attempt to balance your shape toward oval, which is treated as the neutral. Contour narrows what is widest. Blush adds width or lift where it is missing. Highlighter pushes forward whatever you want people to notice.
So the same contour line that sharpens a round face can hollow out a long one. This is the entire reason generic tutorials fail: they were mapped onto the presenter's face, not yours. It is also the reason we are building an app that reads your shape through the camera and draws the map on your own reflection.
If you are stuck between two
Most faces are not a perfect category, and that is fine. Face shape is a starting hint, not a diagnosis. Take the two closest shapes, try both placements, and keep the one that looks like you on a very good day.