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Your renovation quote is $30,000. What will it really cost?
Renovations run over — that is not pessimism, it is history. This template models the overrun and the odds of hidden surprises so you can budget the number you will actually spend, not the number on the quote.
Get this in Google Sheets →The model
Total cost is the contractor quote times an uncertain overrun factor, plus uncertain surprise repairs when the walls come down.
| Contractor quote | $30,000 |
| Overrun factor | 1.0× – 1.15× – 1.6× (uncertain) |
| Surprise repairs | $0 – $3K – $15K (uncertain) |
| Total cost | → simulated |
What Sortia tells you
What the job actually costs, across thousands of scenarios:
P5 (smooth)$35.9K
Median$43.2K
Budget to (P80)$47.8K
P95 (rough)$52.3K
P5 · $35.9Kmedian · $43.2KP95 · $52.3K
The $30,000 quote is a fantasy. Budget the P80 — about $47,800 — and you have an 80% chance of staying under. That $18K gap between the quote and the real budget is exactly the contingency people forget to set aside. Change the quote and the ranges to fit your project.
Try it in your own sheet
- Open Sortia in Google Sheets and choose Start from a template.
- Pick Home Renovation: True Cost — the model loads with the inputs filled in.
- Change the assumptions to fit your situation and press Run.