IELTS Task 1: How to Describe a Line Graph

Line graphs are the most common chart type in IELTS Academic Writing Task 1. They show how data changes over time, and your job is to describe the key trends, comparisons, and notable features — in 150+ words, in about 20 minutes.

The challenge is not understanding the graph. Most candidates can read a line graph perfectly well. The challenge is describing it with precise vocabulary, appropriate grammar, and a clear structure. Candidates who use only "went up" and "went down" will not score above Band 6 in Lexical Resource. Candidates who describe every data point without identifying the overall pattern will not score well in Task Achievement.

This guide gives you the vocabulary, structures, and framework to describe any line graph at Band 7+.

The Line Graph Response Structure

Every line graph response should follow this structure:

Introduction (1-2 sentences)

Paraphrase the graph's title/description. Say what the graph shows, the time period, and the unit of measurement.

Example: "The line graph illustrates the amount of electricity generated from four renewable sources — solar, wind, hydro, and biomass — in Terranovia between 2000 and 2020, measured in terawatt hours."

Overview (2-3 sentences)

Summarise the 2-3 most important trends. No specific numbers.

For detailed guidance on writing overviews, see how to write an IELTS Task 1 overview.

Body Paragraph 1 (3-5 sentences)

Describe the first group of data in detail, with specific numbers.

Body Paragraph 2 (3-5 sentences)

Describe the second group of data in detail, with specific numbers.

How to group data: Pair the lines that behave similarly (e.g., both rising) or that tell a story together (e.g., one rising while the other falls).

Essential Trend Vocabulary

Upward Trends

Verb	Noun	Degree
increase	an increase	slight / gradual / steady / significant / sharp / dramatic
rise	a rise
grow	growth
climb	a climb
surge	a surge	(rapid, large increase)
soar	—	(dramatic increase)

Example sentences:

• "Solar energy production increased significantly from 5 TWh to 45 TWh."
• "There was a sharp rise in wind power generation after 2010."
• "Electricity from biomass grew steadily throughout the period."

Downward Trends

Verb	Noun	Degree
decrease	a decrease	slight / gradual / steady / significant / sharp
fall	a fall
decline	a decline
drop	a drop
plunge	a plunge	(rapid, large decrease)
plummet	—	(dramatic decrease)

Example sentences:

• "Coal consumption declined steadily from 2005 onwards."
• "There was a dramatic drop in oil production between 2015 and 2018."
• "Manufacturing output fell sharply during the recession."

Stability and Fluctuation

Expression	Meaning
remained stable / constant / steady	did not change
levelled off	stopped changing after a period of movement
fluctuated	went up and down repeatedly
plateaued	reached a high point and stayed flat
hovered around [number]	stayed near a particular value with minor variations

Example sentences:

• "Hydro power production remained relatively stable at approximately 20 TWh."
• "After reaching 50 TWh in 2015, wind energy generation levelled off."
• "Gas prices fluctuated between $2 and $4 per unit throughout the decade."

Describing the Rate of Change

• gradually / steadily — slow, consistent change
• rapidly / quickly — fast change
• sharply / dramatically / steeply — sudden, large change
• slightly / marginally — very small change
• approximately / roughly / about — when giving non-exact figures

Grammar Structures for Describing Trends

Structure 1: Subject + Verb + Adverb

"Solar energy production increased dramatically between 2010 and 2020."

Structure 2: There was + Adjective + Noun

"There was a significant increase in solar energy production between 2010 and 2020."

Structure 3: Subject + Experienced/Saw + Noun

"The solar energy sector experienced a dramatic rise during this period."

Structure 4: Describing a Starting and Ending Point

"Solar production stood at 5 TWh in 2000 before rising to 45 TWh by 2020."

"Starting at approximately 10 TWh, wind power generation climbed to 50 TWh over the two-decade period."

Structure 5: Comparing Two Lines

"While solar energy production increased sharply, hydro power remained relatively stable throughout the period."

"Wind power generation, which had been lower than coal production in 2000, overtook it by 2012."

Varying your sentence structures demonstrates grammatical range — a key factor in your Grammar score. Use all five structures across your response.

Describing Specific Data Points

When you mention specific numbers, use these phrases:

• Exact figures: "...reaching 45 TWh in 2020."
• Approximate figures: "...approximately 45 TWh" / "...roughly 45 TWh" / "...around 45 TWh"
• Peaks: "...peaking at 50 TWh in 2015."
• Lows: "...hitting a low of 3 TWh in 2005."
• Starting points: "Starting at 10 TWh in 2000, ..."
• Comparisons: "...nearly double / triple the 2000 figure."

Complete Sample Response

Graph description: A line graph showing electricity generated (in TWh) from solar, wind, hydro, and biomass in Terranovia, 2000-2020.

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The line graph illustrates the volume of electricity produced from four renewable energy sources in Terranovia over a twenty-year period, from 2000 to 2020.

Overall, solar and wind power experienced the most dramatic growth, with solar becoming the dominant renewable source by 2020. In contrast, hydro and biomass generation showed relatively modest changes over the same period.

Solar energy production stood at just 5 TWh in 2000 but increased steadily over the following decade, reaching approximately 15 TWh by 2010. After 2010, growth accelerated sharply, with solar output climbing to 45 TWh by 2020 — a ninefold increase from the starting figure. Wind power followed a similar trajectory, rising from 8 TWh to 40 TWh over the full period, though its growth was more gradual before 2008 and then surged in the final decade.

Hydro power, by contrast, remained the most stable source throughout the period. Starting at around 20 TWh, it fluctuated slightly but never exceeded 25 TWh, ending the period at approximately 22 TWh. Biomass generation showed a more modest upward trend, growing from 3 TWh in 2000 to 12 TWh in 2020 — a consistent but unremarkable increase compared to the rapid expansion of solar and wind.

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Word count: 191

Why this works:

• Task Achievement: Clear overview identifying key trends; all four data lines described with relevant data
• Coherence: Logical grouping (fast-growing sources, then stable sources); clear topic sentences
• Vocabulary: "accelerated sharply," "ninefold increase," "followed a similar trajectory," "fluctuated slightly"
• Grammar: Mix of simple and complex structures; comparative phrases; time clause constructions

Common Line Graph Mistakes

Mistake 1: Describing Every Data Point

Do not describe every year or every value on the graph. Select the most significant points: the start, end, peaks, troughs, and turning points.

Mistake 2: Using Only "Increased" and "Decreased"

Using the same two verbs throughout your response caps your Lexical Resource at Band 6. Use the vocabulary table above to vary your language.

Mistake 3: No Overview

A missing overview is the single most costly mistake in Task 1. Always include 2-3 sentences summarising the main trends before describing the data in detail.

Mistake 4: Giving Your Opinion

Task 1 is a factual report. Never write "I think," "In my opinion," or speculate about reasons for the trends. Just describe what the data shows.

For detailed vocabulary strategies, see how to improve your IELTS Lexical Resource.

Quick Reference: Line Graph Checklist

• Introduction paraphrases the graph description (what, where, when, units)
• Overview identifies 2-3 main trends — no specific numbers
• Data is grouped logically (not described line by line in isolation)
• At least 5 different trend words used (not just "increased/decreased")
• Specific data points included with appropriate precision
• Sentence structures varied (verb+adverb, there was + noun, comparisons)
• No opinions or explanations — just factual description
• 150+ words

Practice Your Task 1 Writing

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