In short: Describe a line graph by reporting how the lines change over time. Write an introduction, a figure-free overview of the overall trend and which line ends highest and lowest, then body paragraphs using trend language (rose sharply, levelled off) with key figures and dates. Match the tense to the period shown.
A line graph in IELTS Academic Writing Task 1 asks you to describe how one or more values change over time. The examiner is not testing your opinion or your maths — they are testing whether you can select the important information and report it accurately in clear, varied language. This guide gives you a reliable method and the exact language to use.
What the examiner wants
The four Task 1 marking criteria reward different things, and a line graph lets you target each one:
- Task Achievement — an overview that states the main trends, plus accurate supporting detail (key figures, highest/lowest points).
- Coherence & Cohesion — a logical order (overview before detail) and linking that groups similar movements together.
- Lexical Resource — precise verbs and nouns of change, not the same word repeated.
- Grammatical Range — a mix of past simple, comparatives, and clauses that combine two movements in one sentence.
A reliable method
- Read the axes and the time span. Note the units and the start and end dates — every sentence anchors to time.
- Find the big picture. Which lines rise overall, which fall, which stay flat? This becomes your overview.
- Write the introduction by paraphrasing the prompt (don't copy it).
- Write a two-sentence overview of the main trends — no figures here.
- Write the detail paragraphs, grouping lines that behave similarly and quoting a few key figures.
- Check tense and number agreement, and that every claim matches the graph.
The language that scores
Describe direction with varied verbs and their noun forms:
- Upward: rose, increased, climbed, grew → a rise / an increase / a climb
- Downward: fell, decreased, declined, dropped → a fall / a decrease / a decline
- No change: remained stable, levelled off, plateaued
- Degree: sharply, steadily, gradually, slightly (adverbs) → a sharp / steady / gradual / slight (adjectives)
Combine a verb with an adverb, or a "there was a + adjective + noun" structure, to vary your grammar:
The figure rose sharply between 1990 and 2000. There was a sharp rise in the figure between 1990 and 2000.
A worked sample answer
Prompt: The graph below shows the population of two towns, Ashford and Brent, from 1990 to 2020.
The line graph compares the number of residents in two towns, Ashford and Brent, over a thirty-year period from 1990 to 2020.
Overall, both towns grew, but Ashford expanded far more quickly and overtook Brent, which rose only modestly before levelling off.
In 1990, Brent was the larger town with around 40,000 residents, compared with Ashford's 25,000. Brent then climbed steadily to a peak of roughly 55,000 in 2010, after which its population plateaued.
Ashford, by contrast, increased sharply throughout the period. It overtook Brent around 2008 and continued to rise, reaching approximately 70,000 by 2020 — almost three times its 1990 figure.
This answer leads with a figure-free overview, groups the two lines by how they behave, and quotes only the most important numbers — exactly what Task Achievement rewards.
Common mistakes to avoid
- No overview, or an overview stuffed with numbers (save figures for the detail paragraphs).
- Listing every data point instead of selecting the important movements.
- Repeating "increase" in every sentence — vary the verb and the grammar.
- Wrong tense — most line graphs are in the past, so use past simple unless the dates are in the future.
Frequently asked questions
What goes in the overview for a line graph? The overall direction (did values mostly rise or fall?) and which line ends highest or lowest — with no specific numbers.
Which tense should I use for a line graph? Past simple for past years; present perfect or future forms if the graph reaches the present or a future date.
Do I describe every point on the line? No. Report the overall trend and the key turning points — peaks, troughs and crossovers — not every individual value.
How do I avoid repeating "increased"? Vary your verbs (rose, climbed, surged, grew), add adverbs (sharply, steadily, gradually) and use noun forms such as "a sharp rise".
Practise this
You now have the method — the fastest way to make it automatic is to write under guidance and get feedback on the exact language. These lessons drill line-graph trend description step by step: