A lot of students seem to be worried about pie charts. Here are some questions to get you thinking about how to describe them:
What does a pie chart always show?
Yes, pie charts always show you percentages because the whole "pie" is always 100%.
Are pie charts used for comparing?
Yes, you can compare the percentages/numbers within a pie chart, or you might have to compare between 2 or more pie charts. "Comparing" will be the main focus of a pie chart task.
Do pie charts show changes (increase, decrease)?
You can only write about increases and decreases if there are 2 or more pie charts and they show percentages for different years (changes over time).
What verb tense would you use to describe pie charts?
Yes, past simple when past years are shown, or present simple if no years are shown.
Here is the example from Cambridge 7 Page101
The pie charts below show units of electricity production by fuel source in Australia and France in 1980 and 2000.
Sumarise the information by selecting and reporting the main features, and make comparisons where relevant.
Write at least 150 words.
The pie charts compare the amount of electricity produced using five different sources of fuel in two countries over two separate years.
Total electricity production increased dramatically from 1980 to 2000 in both Australia and France. While the totals for both countries were similar, there were big differences in the fuel sources used.
Coal was used to produce 50 of the total 100 units of electricity in Australia in 1980, rising to 130 out of 170 units in 2000. By contrast, nuclear power became the most important fuel source in France in 2000, producing almost 75% of the country’s electricity.
Australia depended on hydro power for just under 25% of its electricity in both years, but the amount of electricity produced using this type of power fell from 5 to only 2 units in France. Oil, on the other hand, remained a relatively important fuel source in France, but its use declined in Australia. Both countries relied on natural gas for electricity production significantly more in 1980 than in 2000.