Numbers, Percentages and Approximations in IELTS Writing Task 1
Priyanka from Noida wrote that a share “increased by 10%” when it went from 20% to 30%. It had actually risen by 10 percentage points.
Accurate numbers are part of describing data well. Use approximations like “just under a third”, keep units clear, and know the difference between a percentage increase and a rise in percentage points.
Which phrase fits which figure?
Use an approximation when a figure sits close to a simple fraction, and add “just under”, “just over” or “nearly” to show which side it falls on.
| Figure | Approximation |
|---|---|
| 24% | just under a quarter |
| 26% | just over a quarter |
| 32% | just under a third |
| 35% | just over a third |
| 49% | nearly half |
| 51% | just over half |
| 68% | just over two-thirds |
| 74% | just under three-quarters |
| 77% | just over three-quarters |
| 9.8 million | nearly 10 million |
Check that the phrase still matches the figure. 24% is not “about a third”, and 51% is not “nearly half”.
Percentages or percentage points?
A percentage point is the arithmetic gap between two percentages. A percentage increase compares the gap with the starting figure.
Take an invented town where bus use rises from 20% in 2015 to 30% in 2025. The gap is 10 percentage points. Compared with the starting figure, that is a 50% increase, because 10 is half of 20.
A fall from 30% to 20% works the same way: 10 percentage points, or a drop of one third.
Incorrect: “Bus use increased by 10% between 2015 and 2025.”
Correct: Bus use rose by 10 percentage points, from 20% to 30%, a 50% increase on the 2015 figure.
“Increased by 10%” would mean a rise from 20% to just 22%.
How do you keep the chart’s units?
Read the axis and the labels before you note any figure. If the axis is in thousands and a bar reaches 45, write 45,000, not 45. Repeat the unit with money and weights too, as in “£9.8 million” or “9.8 million tonnes”.
Cambridge’s teaching notes for a sample task make this exact point and add that the data must be presented accurately.
The Band 7 descriptor describes content that is relevant and accurate, and the Band 6 descriptor allows some inaccurate information in areas of detail. A missing “thousand” is an easy way to introduce an inaccuracy.
Words such as hundred, thousand and million stay singular after a number: “five million residents”. Use the plural for an unspecified quantity: “millions of people”. For related words, see our lesson on quantifiers, and to practise saying numbers, try our numbers lesson.
Should you use figures or words?
IDP India’s guide to writing numbers says that in Academic Task 1 you can write a number in words or as it appears in the visual. The Writing test-format page on the IELTS website says nothing about writing numbers in words or figures.
So treat a style as advice and stay consistent. One consistent style is digits for percentages, years and measurements, and words for simple fractions and small counts. It also helps to avoid starting a sentence with a digit, so write “Forty-two per cent” or reword the sentence.
Our posts on pie charts and comparing data show these phrases in full paragraphs.
Tip
Choose two exact percentages in a practice answer, rewrite them as approximations, and check each against the data.
Try It
Write each of these six invented figures with an approximation phrase:
- 19%
- 48%
- 65%
- 82%
- 91%
- 198,000
Show sample answer
- just under a fifth
- just under half
- just under two-thirds
- just over four-fifths
- just over nine in ten
- nearly 200,000
Key Takeaways
- Match each approximation to its figure: just under, just over or nearly.
- A rise from 20% to 30% is 10 percentage points.
- Keep the chart’s unit: 45 in thousands means 45,000.
- Choose digits or words for numbers, and stay consistent.
The bottom line: Approximate the supporting figures, but give the exact figure behind each key feature.