THE MATH, MADE VISIBLE
How it works
Line-item subtotal = materials + labor + permits & fees + fixtures & appliances + disposal & dumpster + other, using amounts from your own quotes and receipts. Sales tax = (materials + fixtures & appliances) × tax rate ÷ 100; labor, permits, disposal and other are not taxed here. Contingency = (subtotal + tax) × contingency rate ÷ 100. Total budget = subtotal + tax + contingency. Remaining to pay = total budget − already paid. Each category’s share is its amount ÷ subtotal. If you enter a ceiling, the difference is ceiling − total budget.
Real project examples
A bathroom budget from quotes
Example amounts entered from quotes, not typical prices: materials $6,000, labor $9,000, permits & fees $400, fixtures & appliances $3,000, disposal $500 and other $1,100 make a $20,000 subtotal. Labor is the largest share at 45%, materials 30%, fixtures 15%. With 0% sales tax and a 15% contingency ($3,000), the total budget is $23,000, all still to pay.
Adding tax, a deposit and a ceiling
The same quotes with 7% sales tax on materials and fixtures add $630 of tax ($9,000 × 7%). A 15% contingency on $20,630 is $3,094.50, so the total budget is $23,724.50. After a $5,000 deposit, $18,724.50 remains to pay, and the plan sits $1,275.50 under a $25,000 ceiling.
Before you commit
- Enter amounts from written quotes, supplier carts and receipts for your own project. This calculator does not supply national or regional cost-per-square-foot prices, because they vary too much by location, scope and finish to plan with.
- Count each cost once. If a contractor quote already includes materials, fixtures or disposal, put the whole quote under Labor (or Other) and leave those categories at zero.
- Sales tax is applied only to materials and fixtures & appliances, at the rate you enter. Whether labor, installation or contractor-supplied materials are taxed depends on your state and on how the contract is written; check your state revenue department or ask your contractor how tax appears on the invoice.
- The 15% contingency is a planning assumption, not a rule. For comparison, HUD’s Standard 203(k) rehabilitation loans set the contingency reserve as a percentage of repair costs, generally 10% to 20%, with at least 10% required for homes 30 years or older and at least 15% when utilities could not be checked. Older homes, opened walls and unclear scopes argue for the higher end.
- Keep the contingency for genuine surprises such as hidden damage or code-required fixes. Upgrades you choose mid-project are new line items; add them to a category so the contingency is still there when you need it.
- Update Already paid as deposits and progress payments go out, and keep the receipts. The remaining figure tells you what still has to be funded, including any unused contingency.
Questions worth asking
How much contingency should I add to a renovation budget?
There is no single right figure. This calculator starts at 15% as an editable planning assumption. HUD’s Standard 203(k) program uses a contingency reserve of 10% to 20% of repair costs, with minimums that rise for homes 30 years or older and when utilities could not be inspected. Use the higher end for older homes or work behind walls, and the lower end for a well-defined, cosmetic scope.
Why is sales tax only applied to materials and fixtures?
Those are the items you or your contractor typically buy at retail. Tax on labor and installation varies by state and by how the contract is written, so it is not added automatically. If your quote shows tax on labor, add it under Other or include it in the labor amount.
Is the contingency included in the remaining amount to pay?
Yes. Remaining to pay is the total budget, contingency included, minus what you have already paid. If the project finishes without using the contingency, your actual spend will be lower than the total.
Can this tell me what my renovation should cost?
No. It totals and organizes the numbers you enter. For quantities, use the material calculators on this site, then price them with your supplier and collect written quotes for labor.
Sources & assumptions
HUD FHA Connection · Standard 203(k) contingency reserve requirementsHUD Handbook 4240.4, Appendix 12 · 203(k) questions and answers (contingency reserve)Last reviewed October 1, 2026. Planning defaults are editable examples. Product labels and supplier information override them.