By Karks Contracting · Published
To estimate a renovation, measure the work, price materials in their actual selling units, separate labour, and list exclusions. A single price per square foot can hide important differences between a cosmetic refresh and a layout change.
Use the free itemized Ontario renovation cost calculator alongside this guide. The result is a planning allowance, not a contractor quote or a claim about average prices in your city.
1. Write the Scope Before Choosing a Budget
List the rooms, surfaces and fixtures being changed. Separate items you are keeping from items you are replacing. Record whether plumbing stays in place, whether walls move, and whether electrical or ventilation work is needed. Photograph the existing space and note moisture, damaged finishes or past alterations that require assessment.
For a kitchen, measure cabinets in linear feet and counters separately in square feet. For a bathroom, distinguish a prefabricated shower from a tiled assembly with its own substrate and waterproofing. For a basement, define the intended use before assuming that finishes alone make up the project.
2. Measure Each Surface Once
A 10-foot by 8-foot room has 80 square feet of floor area. Wall area is different: a simple rectangular room with an 8-foot ceiling has 288 square feet of gross wall area before openings are deducted. Measure irregular rooms in sections and keep ceilings, floors and walls separate.
Enter the actual area assigned to each finish. If half the floor receives tile and half receives another flooring material, do not enter the entire room area for both. Doors, fixtures and lights are counted individually. Roofing requires measured roof surface area, not the room floor area below.
3. Convert Supplier Prices into Installed Quantities
Compare equivalent products and package sizes. A carton price is not a price per square foot. Confirm usable coverage, waste, required accessories and whether the selected material is suitable for the application. Research Canadian material supplier catalogues, including Home Depot, RONA, Home Hardware, Canadian Tire, Tamarack Lumber and Turkstra, then enter the current product quote.
Worked Example: Flooring Packages and Labour
This is a hypothetical arithmetic example, not a current product offer or local market rate. Assume 80 square feet of flooring, 10% material waste, 20 square feet per package, $50 per package and $5 per square foot for labour.
- Material requirement: 80 × 1.10 = 88 square feet.
- Packages: 88 ÷ 20 = 4.4, rounded up to 5 packages.
- Materials: 5 × $50 = $250.
- Labour: 80 × $5 = $400; material waste does not increase installed labour area.
- Subtotal: $650. With the calculator’s 13% HST assumption: $734.50.
This example excludes demolition, subfloor repairs, transitions, trim, delivery and disposal. Add those only if they are needed and not already included in another quoted item.
4. Compare Local Conditions, Not Just City Names
For a Hamilton renovation, document existing structure and building systems before pricing changes. For a project in Burlington, including Aldershot or Millcroft, provide delivery and access details along with your finish selections. In Oakville, flag condominium or heritage considerations where applicable. For a Milton basement project, explain whether the intended space includes bedrooms, a bathroom or a separate dwelling.
These are questions to investigate, not assumptions about every home in a community. The calculator does not increase a price simply because you select a particular city. See all service locations and use the linked local permit guides to find the relevant municipal information.
5. Turn the Allowance into a Comparable Quote
Ask each contractor to identify quantities, material selections, labour, demolition, disposal, permit responsibilities and exclusions. Confirm whether electrical, plumbing, HVAC, inspections and final finishing are included. Check how changes and concealed conditions will be priced before work starts. Never treat an uninspected condition as a fixed cost.
The calculator does not automatically add project setup or contingency charges. Keep any personal reserve separate and discuss risks with your contractor. Review our renovation process and project photographs to prepare your questions.
Use AI to Find Questions, Not Invent Prices
The calculator’s AI brief gathers your selections for optional review in ChatGPT. Ask it to identify missing measurements, possible duplicate work and questions for a contractor. Do not accept invented prices, engineering conclusions or permit advice without verification. Avoid sharing private information you do not want sent to an external AI service.