Formula
Subtotal = materials + labour + permits + tools/delivery/disposal. Contingency = subtotal x contingency percentage. Project estimate = subtotal + contingency.
Home Project Budget Calculator
Build a simple project estimate and see how much contingency adds before you start buying materials.
How to use the result
Use one row for the known quote and one for everything the quote excludes: delivery, disposal, fasteners, protective gear, repairs found during the job and extra paint or material waste.
Useful caution
A project budget is only as strong as the quote detail and measurements behind it. Check real supplier prices and contractor terms before committing money.
Using the Home Project Budget Calculator well
Build a simple project estimate and see how much contingency adds before you start buying materials. Enter realistic values, calculate the first answer, then change one input at a time so you can see which assumption moves the result most.
What to compare
Run a normal case, a cautious case and a stretched case. If the cautious case still works, the number is more useful. If one assumption changes the result sharply, verify that input before relying on the answer.
Project comparison tip
Run one version with the quote as written, then another with a higher contingency or one missing item added back in. If the second version breaks the budget, the project is not as settled as the first estimate suggests.
Before you act
This calculator is a planning aid. It cannot check whether the inputs are complete, current or suitable for a decision with financial, legal, medical, safety or tax consequences.