The pencil test refers to more than one thing depending on context. It is most commonly searched in two senses: a simple at-home check for breast sagging, and a historical method of racial classification used during apartheid in South Africa. Both involve placing a pencil against the body and observing what happens, but they come from vastly different contexts and carry very different significance.
The Breast Pencil Test
The breast version of the pencil test is a quick, informal way to gauge whether breasts have started to sag. You place an ordinary pencil under one breast, right where the underside meets the chest wall (a crease called the inframammary fold). If the pencil stays in place when you let go of the breast, the idea is that the breast tissue is drooping enough to trap it. If the pencil falls to the floor, the breasts are considered self-supporting.
This test became popular as a tongue-in-cheek way to decide whether someone “needs” a bra. The logic: if the breast can’t hold a pencil, it’s firm enough to go braless. Over time, cosmetic surgery discussions adopted it as a rough gauge for whether someone might be a candidate for a breast lift.
Why the Pencil Test Is Unreliable
While the test is easy to do, it tells you very little about the actual state of your breasts. Breast sagging, clinically called ptosis, depends on skin elasticity, tissue density, age, genetics, weight changes, and pregnancy history. The pencil test ignores all of these factors.
A woman with naturally fuller breasts might trap a pencil easily even if her breasts sit high on her chest and show no real sagging. A woman with smaller breasts and genuine mild sagging might not hold the pencil at all. The result depends more on breast size and shape than on actual drooping, which makes it a poor diagnostic tool.
Plastic surgeons assess ptosis differently. The key measurement is where the nipple sits relative to the inframammary crease. If the nipple has dropped to or below that crease, that typically indicates some degree of sagging. This evaluation accounts for individual anatomy in a way the pencil test simply cannot. So while the pencil test might give you a very rough sense of change over time if you repeat it, it is not a meaningful substitute for a professional assessment.
The South African Pencil Test
The pencil test has a much darker meaning in South African history. During apartheid, the government used it as one method of sorting people into racial categories under the Population Registration Act, which required every South African to be classified as white, coloured (mixed racial heritage), or Black. These classifications determined where a person could live, work, go to school, and whom they could marry.
Because a person’s racial background was not always visually obvious, authorities devised crude physical tests to make classifications. In the pencil test, an official would slide a pencil or pen into the hair of a person whose racial group was uncertain. If the pencil fell out, the person “passed” and was classified as white. If the pencil stuck in the hair, the person’s hair was deemed too curly to qualify as white, and they were classified as coloured.
A variation existed for Black South Africans who wanted to be reclassified as coloured, which came with slightly fewer legal restrictions. In this version, the person placed a pencil in their hair and shook their head. If the pencil fell out during the shaking, reclassification was possible. If it stayed, the person remained classified as Black.
How the Test Shaped Lives
The consequences of this test were enormous. Racial classification under apartheid controlled nearly every aspect of daily life. A single test result could separate family members into different racial categories, meaning siblings could be legally forced to live in different areas, attend different schools, and navigate entirely different legal systems. The arbitrariness of basing these life-altering decisions on whether a pencil stuck in someone’s hair underscores how absurd and dehumanizing the apartheid classification system was.
The pencil test’s formal authority ended with the collapse of apartheid in 1994. It remains one of the most widely cited examples of the pseudoscientific methods governments have used to enforce racial hierarchies, and it continues to surface in discussions about systemic racism, identity, and the legacy of colonialism in South Africa.