It gets chosen aesthetically and it behaves mechanically. Two of these five break constantly on most people, and it has nothing to do with how well they were applied.
Straight across, sharp corners. Strongest of the five, because the stress is spread across the whole free edge. Catches on everything, which is why people who type migrate away from it.
Square with the corners softened. Nearly all of the strength, none of the catching. The default answer for most people and the shape that survives the most lives.
Tapered sides, rounded point. Elegant, flattering on almost every hand, and structurally fine as long as the taper starts past the fingertip rather than at the cuticle.
Tapered with a squared tip. Needs length to read at all, which is exactly what makes it fragile. Breaks at the taper point rather than the tip.
Sharp point. All the load lands on a few millimetres of material. Beautiful, and the shape most likely to be back for a repair.
Not at the tip. Almost every break happens at the widest stress point, which is where the sidewall meets the free edge. Square and squoval spread that load across a wide edge. Coffin and stiletto concentrate it, because the taper narrows exactly where the leverage is highest.
This is why a stiletto set at a centimetre breaks more than a square set at two. Length matters, but where the material is matters more.
A wide, short nail bed suits almond and squoval: the taper lengthens the look of the finger. A long narrow bed suits square and squoval and often looks severe in stiletto. A curved (C-curve) bed holds coffin better than a flat one, because the natural curve resists the flex the taper introduces.
Your tech will tell you this in about four seconds of looking at your hand, and it is worth asking rather than arriving fixed on a photograph.
Squoval at a few millimetres past the fingertip is the shape most people should be wearing and the shape that gets asked for least. It survives everything, it suits nearly every hand, and it does not look like a compromise. Almond is the next best answer and is what most people who ask for coffin actually want.
Have them. Just have them knowing the trade: acrylic rather than gel, a proper apex, and a repair or two across a three-week cycle. A repair here is ten minutes and free within the first week, which is a policy that exists precisely because these two shapes exist.
And do not have them the week you are moving house, travelling with luggage, or starting something with your hands. That is not a warning, it is arithmetic.
Square, then squoval. Both spread the stress across a wide free edge. Coffin and stiletto concentrate it at the taper, which is where they break.
Squoval at a few millimetres past the fingertip. It has nearly all of square’s strength without the corners that catch.
Not at the tip. Almost every break happens where the sidewall meets the free edge, which is why tapered shapes fail more than square ones.
Almond or squoval. The taper lengthens the look of the finger. Long narrow beds suit square and squoval and often look severe in stiletto.
It survives everything and suits nearly every hand. Ask at the chair and see what your tech says about yours.
Example interactive prototype. Not a real business. Names, photographs, reviews and figures on this page are illustrative. Identifying details on real client work are changed to protect their privacy. This is what Yeti can build for a nail studio in seven days.