Thornleigh
Median house prices jumped 28.2% in a single year in Thornleigh, from $1,253,050 to $1,606,000, one of the sharpest annual gains in Sydney's upper north shore. University attainment at 58.8% runs 28.7 percentage points above the national rate, placing the suburb in SEIFA decile 10 across all four indices. Despite this academic profile, household income sits in only the 94.6th percentile, not the 99th, suggesting many residents are professionals earlier in their careers rather than peak earners, supported by the mortgage-heavy 44.0% share.
Population
8,898
Median Age
40.0
Household IncomeiMedian weekly household income (ABS Census)
$2,681/wk
DAs (12 months)iDevelopment Applications lodged in the past year
76
Median House
$1.5M
2024-2025 (PSI derived)
At $1,500,000 median (PSI-derived), Thornleigh is priced below upper north shore suburbs like Wahroonga and Turramurra but above the Sydney-wide median. Detached houses (76.5%) dominate, with 44.4% having 4+ bedrooms and 39.0% with 3 bedrooms. The 15.5% semi-detached share provides a townhouse entry point. Mortgage-to-income at 24.1% is manageable on high household income ($2,681/week). The 28.2% year-on-year price surge from $1,253,050 to $1,606,000 is notable but based on just 2 quarters of data, so buyers should treat it cautiously. Train access (9.1% public transport usage) is better than most suburban peers.
For Buyers
At $1,500,000 median (PSI-derived), Thornleigh is priced below upper north shore suburbs like Wahroonga and Turramurra but above the Sydney-wide median. Detached houses (76.5%) dominate, with 44.4% having 4+ bedrooms and 39.0% with 3 bedrooms. The 15.5% semi-detached share provides a townhouse entry point. Mortgage-to-income at 24.1% is manageable on high household income ($2,681/week). The 28.2% year-on-year price surge from $1,253,050 to $1,606,000 is notable but based on just 2 quarters of data, so buyers should treat it cautiously. Train access (9.1% public transport usage) is better than most suburban peers.
For Investors
Renters occupy 23.8% of dwellings at $530/week, and vacancy at 4.1% is close to the metro norm, slightly above the national equilibrium. With 73 development applications in 12 months, including new dwellings and secondary dwellings (granny flats), the suburb is seeing infill activity. Population grows slowly at 0.41% per year (+82 people), driven by overseas migration of +239/year while internal migration is negative at -86/year. This pattern means tenants tend to be overseas arrivals who stay temporarily before moving to cheaper suburbs. Rent-to-income at 19.8% leaves significant headroom for rental increases without hitting tenant stress.
Development Activity
Total DAs
444
Last 12 Months
76
YoY ChangeiYear-over-year change in DA lodgements
+2.7%
Avg DA CostiAverage estimated cost per DA in the past year
N/A
Monthly DA Lodgements
DA Categories
Schools in Thornleigh iICSEA: school advantage index. 1000 = national avg, higher = more advantaged
Thornleigh West Public School
K-6 · 477 students
Normanhurst West Public School
K-6 · 363 students
Demographics
Chinese ancestry (1,307 residents) is nearly as large as the English group (2,628), making Thornleigh one of the more diverse upper north shore suburbs. Overseas-born residents at 37.1% are 15.5 points above the national average. Mandarin (308 speakers), Cantonese (145), Korean (127), and Arabic (114) are the top non-English languages. University attainment at 58.8% is 28.7 points above the national rate, and the 19.8% volunteering rate nearly doubles the national average. Average household size of 2.9 is above the national median, and couples with children dominate at 48.2% of families, compared to around 35% nationally.
Age Distribution
Bedrooms
Dwelling Structure
76.5%
Houses
15.5%
Townhouse
8.0%
Apartment
Tenure
Owner-occupiers control 76.2% of dwellings, above the national average: 32.2% outright and 44.0% on mortgage. Stock is 76.5% separate houses, 15.5% semi-detached, and 8.0% apartments. Prices jumped from $1,253,050 in 2024 to $1,606,000 in 2025, a 28.2% gain, though the 2-quarter data window makes trend confirmation difficult. Rent at $530/week and rent-to-income at 19.8% indicate affordable renting by Sydney standards. Mortgage-to-income at 24.1% is comfortable. The 78.4% residential stability rate suggests a settled community where most households stay year-on-year, typical of family suburbs with school catchment anchoring.
Median House Price Trend
Source: State Valuer-General
Mortgage / mo
$2,800
Rent / wk
$530
HH Size
2.9
Personal Income / wk
$1,025
Vacancy Ratei% of dwellings unoccupied on Census night (ABS 2021)
4.1%
Unoccupied
126
Rent / IncomeiMedian rent as % of household income. Over 30% = housing stress
19.8%
Mortgage / IncomeiMedian mortgage as % of household income. Over 30% = housing stress
24.1%
Community Profile
Languages Spoken at Home
Ancestry
Household Composition
18.8%
Couples, no children
7,830
Total families
Economy & Employment
Healthcare (17.0%), professional/tech services (15.7%), and education (14.2%) are the top three employers, together accounting for 46.9% of the workforce, significantly higher than the national combined share for these sectors. Finance (7.9%) and construction (6.6%) round out the top five. Professionals (1,722) and managers (789) dominate occupations. Unemployment at 4.5% is near the national rate, and full-time employment at 67.3% exceeds the national average. All four SEIFA deciles sit at 10, confirming Thornleigh ranks in the top 10% nationally across every socioeconomic measure.
Unemployment
5.5%
Labour Force
10,813
Unemployed
600
Quarterly Trend
Source: SALM Dec-25
Socio-Economic Indexes (SEIFA)iABS index ranking suburbs from 1 (most disadvantaged) to 10 (most advantaged)
Full-time
67.3%
Part-time
28.2%
Participation
61.3%
Employed
4,120
Occupations
Top Industries
University
58.8%
Postgraduate
19.7%
Born Overseas
37.1%
Dwellings
2,973
Transport to Work
Two primary schools serve the area: Thornleigh West Public (ICSEA 1142, 477 students) and Normanhurst West Public (ICSEA 1136, 363 students), both scoring 136+ points above the national benchmark. Public transport usage at 9.1% is among the highest in this batch, reflecting Thornleigh's train station on the T1 North Shore line. The 4.4% walking/cycling rate adds to non-car options. IRSAD decile 10 confirms top-tier socioeconomic advantage. The 19.8% volunteering rate indicates strong community infrastructure and social engagement above the national norm.
Drive
81.7%
Public Transport
9.1%
Walk / Cycle
4.4%
Work from Home
N/A
Population Forecast
+0.41%/yr
(+82 people/yr)
EstablishedPopulation grows modestly at 0.41% per year (+82 people), projected to reach 20,275 by 2031 from 19,875 in 2025. Overseas migration is strong at +239/year, but internal migration at -86/year partly offsets it. Over the decade, population grew 6.2%, below Sydney's average growth rate. The gentrification score of 10 (not gentrifying) confirms Thornleigh is already established-wealthy rather than transitioning. Real income grew 15.0%, and affordability improved from 57.8% to 54.8% (mortgage-to-median-income), because incomes grew faster than house prices over the longer term, despite the recent 28.2% annual spike.
Historical + Forecast
Hamilton-Perry + Holt smoothing on ERP 2001-2025
Age Cohort Forecast
Primary Driver
Overseas Migration
Net Overseas / yr
+239
Net Internal / yr
-86
Gentrification Signal
Not gentrifying
Strong overseas inflow +239/yr
National Ranking iPercentile rank among ~15,000 AU suburbs. 90% = higher than 90% of suburbs
How Thornleigh compares to ~15,000 Australian suburbs
Frequently Asked Questions
Is Thornleigh a good suburb to live in?
Thornleigh ranks SEIFA decile 10 across all four indices, placing it in the top 10% of Australian suburbs. Schools score ICSEA 1136+, well above the national benchmark. Train access (9.1% public transport) and high volunteering (19.8%) support a family-focused lifestyle. The main barrier is the $1.5M median price, though mortgage stress at 24.1% is manageable for the 94th-percentile household income.
What is the median house price in Thornleigh?
The median house price is $1,500,000 based on PSI-derived 2024-2025 data. Year-on-year data shows a 28.2% jump from $1,253,050 to $1,606,000, though this is based on just 2 quarters and may reflect sample size effects. Long-term trends are more reliable: household income in the 94.6th percentile supports the price level.
What schools are in Thornleigh?
Two government primary schools serve the suburb: Thornleigh West Public School (ICSEA 1142, 477 students) and Normanhurst West Public School (ICSEA 1136, 363 students). Both score more than 136 points above the national benchmark of 1000, reflecting the suburb's high educational attainment (58.8% university-educated residents).
Is Thornleigh safe?
Crime data is not available at the suburb level in NSW reporting. Proxy indicators are strong: SEIFA decile 10 across all measures, 4.5% unemployment, 78.4% residential stability, and a 76.2% owner-occupation rate. These factors typically correlate with below-average crime rates compared to the state median.
Is Thornleigh good for property investment?
The 28.2% annual price gain is eye-catching but based on limited data. Vacancy at 4.1% is reasonable, and $530/week rent offers income. With 73 DAs in 12 months, including secondary dwellings and new houses, infill activity is steady. Population growth is modest at 0.41%, and internal migration is negative (-86/year), so demand relies on overseas arrivals (+239/year). Best suited to long-term holders betting on north shore fundamentals.
How is Thornleigh's population changing?
Population grows slowly at 0.41% per year, adding about 82 people annually. Overseas migration (+239/year) drives growth while internal migration is negative (-86/year). The decade growth rate of 6.2% is below Sydney's average. Chinese ancestry (1,307 residents) is the second-largest heritage group, and 37.1% of residents were born overseas, 15.5 points above the national average.
How to read these comparisons
Phrases like "above the national average" reference the unweighted median across Australian suburbs with more than 1,000 residents, not population-weighted national figures. Suburb-level medians are more useful for ranking suburbs against each other; ABS census headlines are population-weighted (so dominated by Sydney and Melbourne) and can read very differently.
Current baseline (refreshed 2026-05-10): median age 40, university-educated 30.1%, born overseas 21.6%, average household size 2.5 people.
Data sources: ABS 2021 Census (demographics, income, tenure), state Valuer-General (house prices), Department of Jobs SALM (unemployment), ACARA (school ICSEA), state Crime Statistics agencies (offences), council DA portals (development applications). Population forecasts use a Hamilton-Perry cohort model calibrated to ABS ERP.
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