What you practice
Each set draws new pyramids: real countries from the UN’s World Population Prospects 2024 (42 countries, in 1950, 1980, 2000 and 2023) or invented countries built for a stage of the demographic transition. Real sets show real bulges and notches: Japan’s baby booms, the gaps in births left by the world wars in Russia, France and Germany, China’s one-child policy and the migrant workers of Qatar. You read bars, add age groups, work out dependency ratios and sex ratios, name the stage with evidence, explain bulges and notches, compare two pyramids and draw missing bars from a table.
Pick your level first. It sets how the sheet counts the sex ratio and the stages, and every sheet prints the definitions it uses.
Example: Niger and Japan in 2023
In set R9SJ22 (GCSE) the pyramid is Japan in 2023. The UN figures, each rounded to 0.1%, give people aged 0–14 as 11.6% of the population, 15–64 as 58.8% and 65 and over as 29.6%. Total dependency ratio = (11.6 + 29.6) ÷ 58.8 × 100 = 70.1, so about 70 young and old people for every 100 of working age; the old-age ratio alone is 29.6 ÷ 58.8 × 100 = 50.3. Niger’s total in 2023 is higher, about 98, but almost all its dependants are children (47.0% under 15, 2.6% aged 65 and over), so its old-age ratio is only about 5. Open set R9SJ22
What each level asks
| Level | Dependency ratios | Sex ratio | Transition |
|---|---|---|---|
| KS3 / GCSE / IGCSE | Total and old-age | Males per 100 females | Five DTM stages, natural increase per 1,000 |
| AP Human Geography / A level / IB | Young, old-age and total, and what the number means | Males per 100 females | Five DTM stages, rate of natural increase in % |
| CBSE (India) | Young and total | Females per 1,000 males | Three stages, as in NCERT Class 12 |
Questions
How do you calculate the dependency ratio from a population pyramid?
Add the bars for ages 0–14 and for 65 and over, both sexes. Divide by the total for ages 15–64 and multiply by 100. With 30% young, 10% old and 60% of working age: (30 + 10) ÷ 60 × 100 = 66.7 dependants per 100 people of working age.
What is the difference between the young, old and total dependency ratio?
The young ratio counts only people aged 0–14 per 100 aged 15–64, and the old-age ratio only people aged 65 and over. The total ratio adds both groups. A high young ratio points to high birth rates; a high old-age ratio to an ageing population.
How do you find the percentage of people under 15?
On a pyramid drawn in percentages, add the six bars for 0–4, 5–9 and 10–14, males and females. On a pyramid drawn in numbers, add the same bars, divide by the total population and multiply by 100.
How do you work out the sex ratio?
Divide the number of males by the number of females and multiply by 100: males per 100 females, the international way. In India the Census gives it the other way round, females per 1,000 males, so 1,000 × females ÷ males.
How can you tell the DTM stage from a population pyramid?
Look at the base and the top. A very wide base that narrows fast means high birth rates (stages 1 and 2). A base that is narrowing points to stage 3, straight sides to stage 4, and a base narrower than the middle to stage 5. Birth and death rates, if given, settle it.
What causes bulges and notches on a population pyramid?
A bulge on both sides is usually a baby boom: more births in those years. A notch is a gap in births, often during a war or famine. Wide male bars of working age alone usually mean migrant workers, as in Qatar or the United Arab Emirates.
How do you draw a population pyramid?
Draw the age groups up the middle, 0–4 at the bottom. Put males on the left and females on the right, with the same scale on both sides starting at 0 in the middle. Draw each bar out to its value from the table, and label both axes.
Data: United Nations, Department of Economic and Social Affairs, Population Division (2024). World Population Prospects 2024, Online Edition. © July 2024 by United Nations, made available under a Creative Commons license CC BY 3.0 IGO. This site uses an extract: 1 July estimates by sex and 5-year age group for 42 countries and 4 years, ages 85 and over joined into one group, values rounded as shown, short country names. The United Nations does not endorse this site.
Definitions checked October 27, 2026: the UN WPP glossary (dependency ratios per 100 of working age; sex ratio as males per 100 females); NCERT Class 8 Resources and Development, chapter 5 (PDF) (young dependants under 15, elderly over 65); NCERT Class 12 Fundamentals of Human Geography, chapter 2 (PDF) (three-stage demographic transition); Census of India 2011, Declining Child Sex Ratio in Haryana (females per 1,000 males in India); AP Human Geography Course and Exam Description (PDF), topics 2.3 to 2.5 and SPS-2.C.2; AQA GCSE Geography 8035 specification (PDF), OCR GCSE Geography A (J383) and Pearson Edexcel GCSE Geography A specifications (population pyramids and the DTM).