RENOBENCH / PLANNING GUIDE
Plan for uncertainty.
Keep the reserve visible.
A contingency is an identified allowance in your plan. It is not an estimate of every unknown, a bill you must pay, or a substitute for completing the scope.
THE SHORT ANSWER
Calculate a percentage-based reserve by multiplying the defined cost base by your chosen percentage. Add the reserve to that base for a total planned budget. Keep actual expenses in their categories and do not record the entire reserve again as an actual cost.
Separate known work from unresolved questions.
A product you have selected but not yet priced is a known cost category with missing information. An unconfirmed exclusion is another open question. A reserve should not make either item disappear from your to-do list.
Keep an uncertainty list beside the budget. Note the open issue, who can clarify it, whether it affects scope or price, and whether you have already entered an allowance. This helps prevent counting the same issue in several places.
A reserve is a planning calculation.
| Input or result | Fictional example |
|---|---|
| Defined planned base | $9,000 |
| Chosen reserve percentage | 10% |
| Reserve | $9,000 × 0.10 = $900 |
| Total planned budget | $9,000 + $900 = $9,900 |
Know which base the tool uses.
The general Project Budget Builder applies your reserve percentage to entered planned category costs. The bathroom and flooring tools include their calculated material tax in the subtotal before applying the reserve.
The DIY comparison applies a separate percentage to each option’s entered cash base. Your chosen value for your own time is not part of that cash reserve. The Contractor Quote Comparison tool does not add contingency automatically.
Do not spend the same reserve twice.
A reserve is part of the plan, not a separate actual expense. When a real additional cost becomes known, enter that bill or cost in its appropriate category. Do not also mark the whole reserve as spent.
Likewise, if an entered contractor quote already contains an allowance, adding that allowance again can duplicate the amount. Check whether you are changing the plan or recording an actual expense before updating the worksheet.
Review the limit as the plan changes.
If new known costs increase the planned base, a percentage-based reserve changes too. Review the total against your own budget limit rather than focusing only on the percentage.
A positive gap between plan and recorded expenses is provisional while costs are incomplete. The worksheet cannot predict the remaining work, financing needs, or final outcome.
PRACTICAL QUESTIONS
A few useful clarifications.
What contingency percentage should I use?
RenoBench does not prescribe one percentage for every project. Choose and document your assumption in light of your actual scope and unresolved questions, and discuss the plan with appropriate professionals.
Does the reserve mean the money will be spent?
No. It is an allowance in the plan, not a spending target or a predicted bill.
Why does my reserve change when I edit a cost?
A percentage-based reserve is recalculated from the tool’s defined base. If the base changes, the reserve amount changes.
Keep planning with RenoBench.
Prepared by RenoBench. Content revision: October 22, 2026. Examples are illustrative; prices and property-specific requirements must be checked separately.
Planning worksheet. Confirm scope and costs with your contractor.