MalesMales are drawn on the left. Each bar is one age group.
FemalesFemales are drawn on the right. Each bar is one age group.
Age groupsThe upright scale, youngest group at the bottom.
PopulationThe level scale: a longer bar means more people.
PrereproductiveAges 0 to 14. Too young to have children yet.
ReproductiveAges 15 to 44. The band old enough to have children.
PostreproductiveAges 45 and older. Past the ages of having children.
Four shapes 4
Rapid growthA wide base: many young people, so the population grows fast.
Slow growthThe base is a little wider than the middle.
Zero growthSides close to upright: about as many young as middle-aged.
Negative growthA base narrower than the middle: the population shrinks.
How this list was compiled: Every name checked on 2026-10-03 in at least two of these. (1) Wikipedia, Population pyramid, https://en.wikipedia.org/wiki/Population_pyramid (males to the left, females to the right; the population on the level axis and the age groups on the upright axis; expansive, stationary and constrictive pyramids). (2) G. Tyler Miller, Essentials of Ecology (2004), section Population Age Structure, https://archive.org/details/essentialsofecol0000mill (age structure diagrams for rapid, slow, zero and negative growth; ages 0 to 14, 15 to 44 and 45 and older). (3) Russell, Hertz, McMillan and others, Biology: Exploring the Diversity of Life, volume 2 (2016), https://archive.org/details/isbn_9780176598792 (prereproductive, reproductive and postreproductive; male and female; rapid, zero and negative growth; a broad base with rapid growth). (4) Hassenzahl, Hager and Berg, Visualizing Environmental Science (2013), https://archive.org/details/visualizingenvir0000hass (prereproductive 0 to 14 years, reproductive 15 to 44, postreproductive 45 and older; rapid and slow growth). The three books were read by full-text search on the Internet Archive. Licence: own work
The drawing: Drawn for this site on 2026-10-03 by a script from the numbers in this page's data. Own original chart; nothing is traced or copied. Licence: own work
How it works
This age structure diagram worksheet has one large diagram to label: males, females, the two scales and three age bands. Under it are four small diagrams, one for each kind of growth. Print it numbered, or quiz yourself.
Read the full guide
Read one diagram
Each bar is one age group, youngest at the bottom. Males are drawn to the left and females to the right, and a longer bar means more people of that age. The brackets mark three bands: prereproductive, ages 0 to 14; reproductive, 15 to 44; and postreproductive, 45 and older.
Tell the four shapes apart
Look at the base. A wide base that narrows quickly shows rapid growth. A base a little wider than the middle shows slow growth. Sides close to upright show zero growth, and a base narrower than the middle shows negative growth.
Using this as an age structure diagrams worksheet for a class? Print the numbered sheet for students and the named one for yourself.
Questions and answers
Can you label age structure diagrams?
Yes. Label males on the left, females on the right, age groups up the middle and population along the bottom. Then mark the three bands: prereproductive, reproductive and postreproductive.
What are the four types of age structure diagrams?
Rapid growth, slow growth, zero growth and negative growth. The wider the base compared with the middle, the faster the population grows. A base narrower than the middle means the population is shrinking.
What are the three age groups in an age structure diagram?
Prereproductive, ages 0 to 14; reproductive, ages 15 to 44; and postreproductive, ages 45 and older. The size of the youngest band compared with the others shows how the population is likely to change.
Is an age structure diagram the same as a population pyramid?
Yes. Both names are used for a chart of a population by age group and sex. With a growing population it is shaped like a pyramid.