A contingency is money you have not assigned yet
It is there because some home projects expose conditions you cannot price with confidence before work starts. Opening walls can reveal damaged framing. Removing flooring can expose subfloor problems. Tear-off can uncover bad roof decking. The reserve gives you room to respond without pretending those unknowns were already part of the base quote.
Keep known allowances separate
If you already know you have a $2,000 tile allowance, that is not contingency. It is a known budget item with an undecided selection. Keeping the two lines separate makes the budget easier to understand and prevents the same dollars from being counted twice.
Worked example
Say the base scope is $24,000, you have $1,500 in known allowances and you choose a 10% contingency. The calculator adds a $2,400 reserve, giving you a total planning budget of $27,900. If the project finishes without using the reserve, that money remains yours.
When uncertainty tends to be higher
- Older homes with limited documentation
- Projects that open wet walls, roofs or floors
- Structural changes
- Unknown electrical or plumbing conditions
- Work with several trades and inspections
- Renovations where the scope is still changing
When the percentage matters less
On a tightly defined replacement with clear access and no demolition, the more important question may be whether the written scope is complete. A large contingency cannot fix a vague contract.
Owner reserve or contract line item?
Many homeowners prefer to keep contingency outside the contractor's contract and approve changes one by one. Whatever approach you use, require written change orders that explain the condition found, the added scope and the added cost.
See the worked project examples and quote comparison tool for the next step.