IELTS Writing Task 1: How to Describe a Line Graph (Band 7+)

Line graphs are one of the most frequently tested visual formats in IELTS Writing Task 1. They show how data changes over time, and examiners expect you to identify, compare, and describe these changes clearly and accurately. Whether the graph tracks population growth, energy consumption, or tourist arrivals, the fundamental approach remains the same.

In this guide, you will learn a reliable step-by-step method for describing line graphs that consistently earns Band 7 and above.

Understanding What the Examiner Wants

Before you write a single word, understand the four criteria that determine your Task 1 score:

1. Task Achievement — Did you cover all key features and provide an overview?
2. Coherence and Cohesion — Is your response logically organized with clear linking?
3. Lexical Resource — Did you use a range of vocabulary accurately?
4. Grammatical Range and Accuracy — Did you use varied sentence structures correctly?

For line graphs specifically, Task Achievement is where most candidates lose marks. You must write a clear overview and select the most significant features rather than describing every single data point.

Step-by-Step Approach to Line Graphs

Step 1: Analyse the Graph (2-3 Minutes)

Spend the first few minutes studying the graph before writing. Ask yourself:

• What does the x-axis show? (usually time)
• What does the y-axis show? (the measured quantity and units)
• How many lines are there?
• What is the overall trend for each line?
• Are there any significant similarities or differences between lines?
• Are there notable peaks, troughs, or turning points?

Step 2: Write the Introduction (1-2 Sentences)

Paraphrase the question prompt. Do not copy it word for word.

Original prompt: "The graph below shows the number of international students enrolled in three universities between 2000 and 2020."

Paraphrased introduction: "The line graph illustrates how international student enrolment at three universities changed over a twenty-year period from 2000 to 2020."

Step 3: Write the Overview (2-3 Sentences)

The overview should describe the most noticeable general trends without specific numbers. Think of it as a summary that someone could read without looking at the graph.

Example overview: "Overall, all three universities experienced growth in international enrolment over the period, although the rate of increase varied significantly. University A saw the most dramatic rise, while University C showed relatively modest growth."

Step 4: Write the Body Paragraphs (2 Paragraphs)

Group related information logically. For line graphs, common grouping strategies include:

• By trend direction — lines that went up vs. lines that went down
• By time period — first half of the period vs. second half
• By category — each line described in turn (works best with 2-3 lines)

Include specific data points to support your descriptions, but do not list every number on the graph.

Essential Trend Vocabulary

The vocabulary you use to describe movements is critical for your Lexical Resource score. Here are the key terms organized by type of change:

Upward Trends

• rose, increased, grew, climbed, surged, soared
• a sharp/significant/steady/gradual/slight increase/rise/growth

Downward Trends

• fell, declined, decreased, dropped, plummeted, sank
• a sharp/significant/steady/gradual/slight fall/decline/decrease/drop

No Change

• remained stable, stayed constant, levelled off, plateaued, held steady

Fluctuation

• fluctuated, varied, was erratic, experienced ups and downs

Speed and Degree Modifiers

• Dramatic change: sharply, dramatically, significantly, considerably, steeply
• Moderate change: moderately, noticeably, steadily
• Small change: slightly, marginally, minimally, modestly

Sample Answer With Annotations

Question: The line graph shows the amount of electricity generated from three renewable sources (wind, solar, and hydropower) in Country X between 2005 and 2025.

Introduction: The line graph compares electricity generation from wind, solar, and hydropower in Country X over a twenty-year period starting in 2005.

Overview: Overall, wind power saw the most remarkable growth and eventually became the leading source of renewable electricity, overtaking hydropower. Solar energy also increased substantially, while hydropower output remained relatively stable throughout the period.

Body Paragraph 1: In 2005, hydropower was the dominant renewable source, generating approximately 50 terawatt-hours (TWh), compared to just 10 TWh from wind and a negligible amount from solar. Over the following decade, wind power climbed steadily, reaching around 40 TWh by 2015, at which point it nearly matched hydropower, which had risen only marginally to 55 TWh.

Body Paragraph 2: Between 2015 and 2025, the gap between wind and the other sources widened considerably. Wind generation surged to approximately 95 TWh, making it the primary renewable source by a significant margin. Solar energy, which had grown gradually to about 15 TWh by 2015, experienced a sharper rise in the second decade, reaching roughly 45 TWh in 2025. Hydropower, by contrast, fluctuated slightly before settling at around 58 TWh, showing only minimal growth overall.

This sample answer demonstrates several important techniques:

• The introduction paraphrases the question
• The overview identifies the biggest trends without numbers
• Body paragraphs are organized by time period (2005-2015, then 2015-2025)
• Specific data supports each claim
• Vocabulary varies throughout

Common Mistakes to Avoid

1. No overview — This is the single most common reason for scoring below Band 6 in Task Achievement
2. Describing every data point — Select 4-6 key data points, not every year
3. Using informal language — Avoid "went up a lot" or "crashed down"
4. Including personal opinions — Task 1 is purely descriptive; never write "I think" or "In my opinion"
5. Writing under 150 words — You will lose marks; aim for 170-190 words

Useful Sentence Structures

Here are versatile structures you can adapt for any line graph:

• "The number of X rose from [figure] in [year] to [figure] in [year]."
• "There was a [adjective] increase in X between [year] and [year]."
• "X and Y followed a similar upward trend, although X grew at a faster rate."
• "While X experienced steady growth, Y remained largely unchanged."
• "After reaching a peak of [figure] in [year], X declined sharply to [figure]."
• "By the end of the period, X had overtaken Y as the highest/lowest category."

How to Practise Effectively

The best way to improve your Task 1 line graph skills is through regular, focused practice with feedback. Here is a recommended routine:

1. Find or generate a line graph task — You can practice writing with AI-generated tasks on CambPrep
2. Time yourself strictly — 20 minutes maximum
3. Check your work against the criteria — Does it have an overview? Varied vocabulary? Specific data?
4. Get feedback — AI-powered evaluation can give you instant band score estimates and targeted advice

If you are unsure about your current level, you can take a level test to identify your strengths and weaknesses before diving into focused practice.

Frequently Asked Questions

How many words should I write for Task 1?

The minimum requirement is 150 words, but you should aim for 170-190 words. Writing significantly more than 200 words means you are probably including unnecessary detail and wasting time that should go to Task 2.

Should I include an introduction AND an overview?

Yes. The introduction paraphrases the question (1-2 sentences), and the overview summarises the main trends (2-3 sentences). Some candidates combine them into one paragraph, which is acceptable, but separating them makes your structure clearer.

What if there are too many lines on the graph?

If there are four or more lines, group them by trend. For example, describe the lines that increased together and then the lines that decreased. You do not need to give equal attention to every line — focus on the most significant patterns.

Can I use "approximately" and "about" when describing data?

Absolutely. Unless a number is clearly marked and easy to read precisely, you should use approximation language such as "approximately," "about," "roughly," or "just over/under." This shows the examiner you understand that reading exact values from a graph is not always possible.