How much contingency money should I keep for a renovation?
Plan on 10 to 15 percent of the project cost for new or recently updated homes, and 20 percent or more for houses built before 1980 or for any project that opens walls, floors or the roof deck. The contingency is for conditions you could not see, not for upgrades you decide you want mid-project. Keeping those two buckets separate is what prevents a budget from quietly doubling.
Reviewed by Owners & Homes · Published February 24, 2026 · Last reviewed September 2, 2026
Suggested contingency by project
- Cosmetic work, newer home
- 10%
- Kitchen or bath, home under 30 years old
- 15%
- Any project in a pre-1980 home
- 20%
- Structural work, additions, foundations
- 20 – 25%
What affects the answer
- Age of the home and the likelihood of outdated wiring, plumbing or framing.
- How much of the structure is being opened up.
- How complete the drawings and specifications are before work starts.
- Whether allowances in the bid are realistic or artificially low.
What homeowners often overlook
- Allowance overruns are the most common budget surprise, and they are not truly unforeseen conditions.
- Code upgrades triggered by the permit, such as smoke alarms or arc-fault protection throughout.
- Living costs during the project — meals out, a hotel, storage.
- Sales tax and delivery fees on materials you supply yourself.
- The last five percent: hardware, paint touch-ups, blinds, small fixes after final walkthrough.
Questions to ask before hiring
- What allowances are in this bid, and are they based on real product selections?
- What unforeseen conditions do you expect in a house of this age?
- How will you notify me before spending against contingency?
A practical next step
Set your contingency aside as a separate number before you approve any scope. If it is inside your project budget, you will spend it on upgrades.
This is general planning information, not an appraisal, engineering opinion, financial advice or a contractor proposal. Costs, timelines and property-value effects vary according to location, scope, materials, workmanship, property condition and market activity.