Renovation Cost Estimator
Budget a renovation with a realistic range and contingency.
Finish multiplier. 1 = baseline, 1.5 = high-end, 0.8 = budget.
Optional. Permits, fees, and other one-off costs added on top.
Reserve for overruns, as a percentage of the base estimate.
Estimated total
- Likely range
- $159,750.00 – $195,250.00
- Base estimate
- $150,000.00
- Contingency reserve(15%)
- $22,500.00
- Fixed costs
- $5,000.00
Estimate. The likely range is the estimated total ±10%, so your total always falls inside it. The total is the base plus the contingency reserve plus any fixed costs (permits, fees).
How the renovation cost estimator works
The estimator starts from a base cost, which is your floor area multiplied by a cost per unit area and a quality multiplier. If your area and your unit cost use different units, the area is first converted so both sides match, using the exact factor 1 m² = 10.7639 ft². In plain terms the base is base = area × unitCost × qualityFactor.
From that base it derives the rest. The contingency is a reserve sized as a fraction of the base, contingency = base × contingencyPct, defaulting to 15%. The total adds the contingency and any fixed costs to the base: total = base + contingency + fixedCosts. The low and high ends of the range then flex that total by a spread: low = total × (1 − spread) and high = total × (1 + spread), defaulting to a 10% spread, so the headline total always sits inside its own range. Every output is rounded to the cent at the end.
Worked example
Suppose you are renovating a 200 sq ft kitchen at a unit cost of 250 per sq ft, with a baseline finish (quality factor 1), the default 15% contingency, the default 10% spread, and 3,000 in fixed costs for permits and a designer fee.
| Step | Calculation | Result |
|---|---|---|
| Base | 200 × 250 × 1 | 50,000 |
| Contingency | 50,000 × 0.15 | 7,500 |
| Total | 50,000 + 7,500 + 3,000 | 60,500 |
| Low | 60,500 × 0.90 | 54,450 |
| High | 60,500 × 1.10 | 66,550 |
So the base construction cost is 50,000, and once the 15% reserve and the fixed costs are added the planning total is 60,500, with a likely range of 54,450 to 66,550 after flexing that total by the default 10% spread.
How to use it
- Enter the area you are actually renovating, not the whole property, unless every room is in scope.
- Match or convert your unit cost: pull a per-square-foot or per-square-meter figure from a recent quote or a local cost guide, and the tool will reconcile the units for you.
- Set the quality factor to reflect finish level only if your unit cost does not already account for it, so you do not double-count premium materials.
- Keep permits, design fees, and appliances in fixed costs, since they do not scale with area.
- Plan your budget against the total, and treat the high end of the range as the figure to confirm you can cover before signing a contract.
Limitations
This is a planning estimate, not a quote or professional advice. It assumes a roughly uniform cost across the whole area, so it will not capture structural surprises, asbestos or mold remediation, custom one-off features, or large price swings between regions and contractors. The contingency is a flat percentage and does not know how risky your specific project is: older buildings and full gut renovations often warrant a larger reserve. Always confirm scope and pricing with at least two written contractor bids before committing funds.
Frequently asked questions
Why does the estimate show a range instead of one number?
Renovation prices vary by contractor, material choice, and site conditions, so a single figure overstates how precise an early estimate can be. The tool sets the range by flexing the total by the spread, defaulting to plus or minus 10%. Use the low end for best-case bids and the high end for planning your cash reserve.
Is the contingency included in the low and high range?
Yes. The low and high values flex the total, which already includes the base, the contingency reserve, and any fixed costs. So the range brackets your full planning total, and the headline total always sits inside it.
Can I mix square feet and square meters?
Yes. You can enter the area in one unit and the unit cost priced in another, and the tool converts the area to match the cost using the exact factor 1 m squared = 10.7639 ft squared. The base is always area and cost expressed in the same unit before multiplying.
What should I put for the quality factor?
Leave it at 1 if your unit cost already reflects the finish you want. Raise it above 1 for premium materials, custom millwork, or high-end fixtures, and lower it below 1 for a budget refresh. It multiplies the base directly, so 1.2 adds 20% across the whole job.
What belongs in fixed costs?
Anything that does not scale with floor area: permit fees, architect or designer fees, dumpster rental, or appliance purchases. These are added to the total after the contingency and are not affected by the spread or quality factor.