Free planning tool · Toronto additions
What would your addition actually cost? Price it yourself from our 100+ completed builds. No email required.
Build an estimate in about a minute, priced from our database of completed Toronto home additions, and the math is right here in the open.
Est. 1997 · 100+ additions completed · Fixed-price contracts · Featured in CBC, Toronto Star & Fortune
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The calculator
Set up your project. Watch the number build.
Every line is priced the way we price a real job: from the scope you set, line by line.
The square footage your home occupies on the property, measured outside.
How many floors sit above ground today.
A top-up adds a storey. An extension grows the footprint.
Reworking the existing rooms, not just the new space.
Entry-level runs roughly $25,000–$40,000, mid-range $40,000–$70,000, higher end $70,000–$150,000.
Inside measurements are fine here.
Count a powder room as 0.5.
ESTIMATED HOME ADDITION INVESTMENT
Set the size of your top-up or extension above and your estimate builds here, line by line.
Approximate, before HST, based on your inputs and our database of completed home addition projects. Zoning, structure, and finishes move real numbers, so treat this as your starting math. A fixed price comes after design and feasibility work.
Where the numbers come from
These numbers come from real projects, not internet averages.
Every line in this estimate is priced from top-ups, extensions, kitchens, and bathrooms we have actually built in Toronto. One of those project budgets is published line by line in the cost guide, so you can check our math against an actual build.
What no calculator can see: your zoning, your structure, your soil, and the condition of what's already there. That's why the number above is a starting point, and why the next two steps exist.
From estimate to real number
Three steps, each one more certain than the last.
A planning-level number. Enough to know whether the conversation is worth having.
Fifteen pages of cost tables, a fully published project budget, Toronto zoning explained, and the honest stay-or-move math.
An hour with our pre-construction team, then a written feasibility report: what your lot allows, what it will really cost, and how long design and permits take. Credited in full toward your project.
Free download
Take the real numbers with you.
The Toronto Home Addition Cost Guide 2026: the cost tables behind this calculator, a real project budget published in full, and the five red flags to watch for in any quote.
Common questions
It's a planning-level number built from the projects we have completed. What moves it in real life: structural surprises, zoning constraints, soil conditions, and your finish choices. Families who want a number they can plan against book the feasibility session.
No. A real fixed price comes after design and feasibility work, and that's exactly the order we recommend doing it in, with us or with anyone else. What this gives you is the starting math most builders keep to themselves.
Design fees, permits, and approvals are separate, and the cost guide walks through what those cost and how long they take in Toronto. Figures shown are before HST.
Because the alternative is the industry standard: vague estimates until you've spent $15,000–$30,000 on drawings. We'd rather you have the real math on day one. It's the same reason one of our full project budgets is printed in the guide.
Walk into every builder conversation already knowing your number.
Start with the estimate, take the guide with you, and get your property's exact answer when you're ready.