Home Renovation Cost Calculator
Work out what a whole-home renovation will cost — your costs per category, plus a contingency and tax, with nothing priced by the site.
A renovation is a dozen quotes in a trench coat. This calculator is the trench coat's pocket: put every category's cost in, add a contingency and tax, and see the real total.
All prices are entered by you. This site publishes no construction prices, and results are estimates, not guaranteed quotes.
Your results
Enter your measurements and press Calculate.
Quantities are rounded up to whole tiles, planks, boxes or bags, after the wastage allowance. Cost appears only when you enter a price.
Formula
All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.
How to use this calculator
- Enter your cost for each category (0 if not included).
- Set a contingency — 10–20% is normal.
- Enter your local tax rate.
- Read the subtotal, contingency, tax and total.
Worked example
| Categories | Kitchen $15,000 + Bathroom $8,000 + Flooring $5,000 + Painting $3,000 + Other $2,000 |
|---|---|
| Subtotal | $33,000 |
| Contingency (10%) | $33,000 × 0.10 = $3,300 |
| Tax (8%) | ($33,000 + $3,300) × 0.08 = $2,904 |
| Total | $33,000 + $3,300 + $2,904 = $39,204 |
Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.
Frequently asked questions
How much does a home renovation cost?
It depends entirely on the scope and your local prices — which is why this calculator asks for your figures instead of guessing. Enter each category from your quotes, add a contingency and tax, and the total follows.
How much contingency should I allow?
10% for a straightforward job, 15–20% for an old house or a job with unknowns (hidden damp, old wiring, structural surprises). The contingency is the most under-budgeted part of most renovations.
Is tax applied to the contingency too?
In this calculator, yes — tax is applied to the subtotal plus the contingency, which is how most jurisdictions tax the work as billed. If your local rules differ, adjust the tax rate to match.
Are these figures a quote?
No. They are estimates built from your own numbers — not guaranteed quotes. Get written quotes from contractors for the real price, and use this calculator to check them.
Related calculators
Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.