For early planning, use a broad range and then let the written contractor scope replace the calculator. The biggest pricing errors come from assuming every roof of the same size is the same job.
Start with a range, not a single price
A roof price is the result of several variables multiplied together: roof surface area, material, slope, shape, height, access, tear-off depth and local market conditions. That is why a square-foot number can be useful for early planning but misleading if it is treated as a quote.
HomeSelect's Ontario calculator deliberately produces a broad rounded range. It is designed to answer a budgeting question — whether the project looks closer to ten thousand dollars or twenty thousand dollars — before you give anyone your contact information.
What the current HomeSelect model assumes
For a typical asphalt roof, the model starts with a broad $5.25–$9.25 per square foot planning band before multiplying for city, material, pitch, complexity, access and tear-off. Results are rounded to the nearest $250 so the tool does not imply precision it cannot know from a browser.
Sample Ontario planning ranges
Using an approximately 1,800-square-foot roof, asphalt shingles, typical pitch and complexity, two-storey access and one existing layer, the current model produces the following broad planning examples. These are not market quotes and should not be used to value a contractor's work.
- Toronto: about $10,500–$18,750, model midpoint about $15,000.
- Ottawa: about $9,750–$17,000, model midpoint about $13,750.
- Hamilton: about $9,750–$17,250, model midpoint about $14,000.
- London: about $9,250–$16,250, model midpoint about $13,250.
- Kitchener/Waterloo/Cambridge: about $9,500–$16,750, model midpoint about $13,500.
What can push an actual quote higher
The calculator cannot inspect the roof. Decking rot, damaged sheathing, complicated flashing, skylights, chimneys, ventilation changes, structural repairs, difficult staging, disposal constraints and specialty products can all materially change the actual contractor price.
A complex roof with multiple valleys and steep sections also takes more labour and safety setup than a simple low-slope gable of the same surface area.
- Multiple tear-off layers or heavy old materials.
- Steep pitch, three-storey height or restricted access.
- Large amounts of flashing around walls, chimneys or skylights.
- Decking replacement that cannot be known until tear-off.
- Premium asphalt, metal or specialty roofing systems.
- Ventilation, eaves protection or drainage work added to the scope.
How to compare the contractor price to the planning range
Do not reject a quote simply because it sits above an online range. First compare what the contractor actually included. A lower number that excludes disposal, flashing, ventilation, cleanup, permits or foreseeable repairs may not be cheaper once the work begins.
Ontario's consumer guidance emphasizes written estimates and written contracts. The province also advises homeowners to compare written estimates. HomeSelect can seek one matched contractor for your request; you remain free to obtain additional estimates independently if you want a broader comparison.
Ask for the scope in writing
Before signing, make sure the written agreement identifies the work, materials, payment terms, schedule, warranties and how changes will be handled. Those details matter more than whether an online midpoint happened to be close.
Use the calculator before the form
The Ontario roofing calculator sits above the HomeSelect request form on purpose. You can build the range privately, change the assumptions, and decide whether you are ready to speak with a contractor. If you are, the city, material and estimated range can carry into the request so you do not have to type the project twice.
Build a quote-comparison worksheet before anyone visits
A planning range becomes much more useful when you pair it with a simple scope worksheet. Write down the roof area assumption you used, the current material, number of storeys, approximate pitch, visible valleys or dormers, known leaks, skylights or chimneys, and whether you suspect more than one existing layer. Give each contractor the same starting information, then let them correct it after inspection.
When the written estimates arrive, compare the categories rather than only the total. Look for tear-off, disposal, underlayment, eaves protection, flashing, ventilation, decking allowances, cleanup, warranty and taxes. If one estimate does not mention an item that another includes, ask before treating the lower total as a true saving.
Budget a contingency without pretending every surprise will happen
Roofing is one of the projects where some conditions stay hidden until the old material comes off. That does not mean you should automatically add every possible repair to the budget. Instead, ask the contractor which hidden conditions are plausible for your roof and how they will be priced if found.
A useful contract can include a unit price or allowance for common hidden work such as decking replacement. That creates a more controlled contingency than an undefined promise that “extras will be discussed later.” The online calculator cannot know those conditions, so keep part of your budget flexible until the roof is opened.
Ready to move from planning to a roofer?
Use HomeSelect once. Where current Ontario coverage is available, we seek one local roofer whose service area and project fit match the request.
Official sources and further reading
HomeSelect summarizes these sources for planning. Confirm current legal, permit and safety requirements with the responsible government body and your municipality before work starts.