Heart and diamond faces both narrow to a fine chin, so they are easy to confuse. The difference is the widest point. On a heart face the forehead is as wide as the cheekbones or wider; on a diamond face the forehead is clearly narrower, so the cheekbones stand out as the widest part. One measurement, forehead divided by cheekbones, settles it. The Face Shape Calculator does it with your four measurements.
What heart and diamond faces share
Both shapes have a jaw much narrower than the cheekbones: about 0.65 to 0.80 of the cheekbone width for heart, 0.70 to 0.85 for diamond. Both are moderately long, with length-to-width ratios in the same middle band of the face shape chart. Seen from the chin up, they look the same.
So two of the three ratios point both ways, and everything depends on the forehead. Both shapes are styling reference points, not anatomical categories, which is why a face can land on the border.
The deciding measurement: forehead against cheekbones
Measure your forehead (A) at its widest, usually about halfway between brows and hairline, and your cheekbones (B) at their most prominent points, both straight across. Divide A by B.
- 1.00 or above: the forehead is the widest point. Heart.
- About 0.88 or below: the cheekbones are clearly widest, with the face narrowing above and below them. Diamond.
Take the forehead measurement with every bit of hair pinned back, including at the temples. Hair falling over the temple edge hides the forehead width and can turn a heart into a diamond on paper. If your hairline dips at the temples, measure the bone line where the forehead is widest, not where the hair starts.
Example numbers: the forehead decides
Here is how the calculator scores a face with a jaw at 0.75 of the cheekbones and a length ratio of 1.40, as only the forehead changes:
| A/B (forehead) | Top result | Runner-up |
|---|---|---|
| 0.78 | Diamond 94 | Heart 72 |
| 0.86 | Diamond 92 | Oval 72, heart 72 |
| 0.90 | Diamond 83 | Oval 81 |
| 0.94 | Oval 86 | Heart 76, diamond 76 |
| 0.98 | Heart 83 | Oval 81 |
| 1.06 | Heart 97 | Diamond 72 |
The table shows something most charts leave out: between heart and diamond lies oval. With a forehead at about 0.90 to 0.98 of the cheekbones, a narrow jaw is simply the oval taper. If your numbers land there, read the oval face shape guide alongside the two below.
Two full examples:
- Heart: forehead 13.5 cm, cheekbones 13 cm, jaw 9.5 cm, length 18 cm. Ratios 1.04, 0.73 and 1.38. Heart 98, diamond 67.
- Diamond: forehead 11 cm, cheekbones 14 cm, jaw 10.5 cm, length 20 cm. Ratios 0.79, 0.75 and 1.43. Diamond 96, heart 70.
Heart vs diamond face at a glance
| Heart | Diamond | |
|---|---|---|
| Widest point | Forehead | Cheekbones |
| Forehead (A/B) | 1.00 to 1.12 | 0.75 to 0.88 |
| Jaw (C/B) | 0.65 to 0.80 | 0.70 to 0.85 |
| Length (D/B) | 1.25 to 1.50 | 1.30 to 1.55 |
| Outline | Wide at the top, tapering down (some charts call it inverted triangle) | Narrow at top and bottom, wide in the middle |
What changes between them
Both shapes benefit from fullness around the jaw and chin, where the face is narrowest: a lob, waves that start at the jaw, earrings that are wider at the bottom. The difference is at the top. A heart face already carries width at the forehead, so the aim is to keep it light, with side-swept bangs, little height at the crown and frames with a thin or rimless upper edge. A diamond face is narrow at the forehead, so the aim is the reverse: add width there with bangs or a deep side part and frames with a defined top line, and keep volume away from the cheekbones.
The full advice is in the heart face shape and diamond face shape guides, and frames for the first are covered in glasses for a heart-shaped face.