Start from a documented quantity or cost
Enter the base amount that the percentage should apply to — a material subtotal, a labour figure or another known line. Do not use a placeholder you cannot explain later.
- Waste belongs with the material that creates it, not as a hidden global bump when you can be specific.
- Markup, overhead and contingency are different decisions; do not stack them twice.
- Tax depends on jurisdiction and what is taxable; the rate is an input, not advice.
Apply components in the order you will explain them
Use material-waste with a quantity. Use markup, tax and contingency on cost bases after quantities exist. Then return to the estimate draft so each component stays a line, not a mystery percentage inside a total.
Percentages are not purchase orders
These calculators output adjusted amounts. Supplier terms, retainage, discounts and allowances still belong in the commercial document.
- Write the reason for each percentage in the estimate notes.
- Replace defaults before sending a quote.
- Do not present a planning markup as a market rate.
Planning boundary
These tools display arithmetic. They do not set a legally compliant price, tax opinion or bid strategy.