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Build vs Buy

Should you build a brand-new home or buy an existing one? Compare the two side by side over your time horizon — accounting for buying costs, higher maintenance on an older home, construction cost overruns, council fees and paying to live elsewhere while a new build is underway. Everything stays in your browser.

Your situation

yrs
$

Applied equally to both paths

%
yrs
%/yr

🏡 Buy an existing home

$
%

Legal, inspection, moving

%/yr

Of home value, per year

🏗️ Build a new home

$
$
%

Contingency on construction

$

Council, design, connections

mo
$/mo
%

Finished value vs money spent

%/yr

Of home value, per year

Results update live as you edit these figures — everything stays in your browser.

Saved comparisons

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Run a comparison and choose "Save" to keep it here. Saved comparisons live in this browser only — no account required.

Showing an example comparison based on typical inputs. Edit any figure on the left and these numbers update instantly to match your own situation.

The Two Paths

🏡 Buy Existing

Projected net position

$213,096
Cash needed upfront
$162,750
Home value at horizon
$1,547,256
Mortgage remaining
$507,914
Total cash spent
$826,247
Better Value
🏗️ Build New

Projected net position

$272,549
Cash needed upfront
$185,000
Home value at horizon
$1,643,663
Mortgage remaining
$561,202
Total cash spent
$809,912

Net Position Over Time

$0k$68k$136k$204k$273kY1Y3Y5Y7Y9Y11Y13Y15
Buy ExistingBuild New

Net position is your home equity (value minus mortgage) less every non-equity dollar spent along the way — interest, maintenance, rent while building and one-off costs. Higher is better. The build line dips early (rent and interest with no home yet) then jumps when the build completes.

Key Findings

Better financial choice

Build New

Based on projected net position at your horizon

Net position gap

$59,453

Difference between the two paths at your horizon

Extra cash to start a build

$22,250

Upfront cash for building vs buying (deposit + one-off costs)

Total cash spent (build)

$809,912

Interest, maintenance, rent-while-building and one-off costs

Our Recommendation

Building comes out ahead by about $59,453 over 15 years, once buying costs, maintenance, cost overruns and paying to live elsewhere during a build are all accounted for.

Informational only, not financial advice. Figures are pre-tax estimates and don't account for market volatility, build delays beyond the time you enter, or your personal tax situation. Build costs in particular vary widely — use your own quotes.