function calculateRehab() {
// 1. Get Property Values
var purchasePrice = parseFloat(document.getElementById('purchasePrice').value) || 0;
var arv = parseFloat(document.getElementById('arv').value) || 0;
// 2. Get Repair Costs
var roofCost = parseFloat(document.getElementById('roofCost').value) || 0;
var extCost = parseFloat(document.getElementById('extCost').value) || 0;
var hvacCost = parseFloat(document.getElementById('hvacCost').value) || 0;
var plumbingElecCost = parseFloat(document.getElementById('plumbingElecCost').value) || 0;
var kitchenCost = parseFloat(document.getElementById('kitchenCost').value) || 0;
var bathCost = parseFloat(document.getElementById('bathCost').value) || 0;
var flooringCost = parseFloat(document.getElementById('flooringCost').value) || 0;
var paintCost = parseFloat(document.getElementById('paintCost').value) || 0;
var landscapingCost = parseFloat(document.getElementById('landscapingCost').value) || 0;
var permitsCost = parseFloat(document.getElementById('permitsCost').value) || 0;
var contingencyPct = parseFloat(document.getElementById('contingencyPct').value) || 0;
// 3. Logic & Calculations
var baseRehab = roofCost + extCost + hvacCost + plumbingElecCost +
kitchenCost + bathCost + flooringCost + paintCost +
landscapingCost + permitsCost;
var contingencyAmount = baseRehab * (contingencyPct / 100);
var totalRehab = baseRehab + contingencyAmount;
var totalInvestment = purchasePrice + totalRehab; // Simplified (excludes closing costs for this tool)
var profit = arv – totalInvestment;
var roi = 0;
if (totalInvestment > 0) {
roi = (profit / totalInvestment) * 100;
}
// 70% Rule Calculation: (ARV * 0.7) – Repairs
var mao = (arv * 0.70) – totalRehab;
// 4. Formatting Currency
var currencyFormatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 0,
maximumFractionDigits: 0
});
// 5. Update DOM
document.getElementById('resultSection').style.display = 'block';
document.getElementById('baseRehabDisp').innerText = currencyFormatter.format(baseRehab);
document.getElementById('contingencyDisp').innerText = currencyFormatter.format(contingencyAmount);
document.getElementById('totalRehabDisp').innerText = currencyFormatter.format(totalRehab);
document.getElementById('purchaseDisp').innerText = currencyFormatter.format(purchasePrice);
document.getElementById('totalInvestmentDisp').innerText = currencyFormatter.format(totalInvestment);
document.getElementById('arvDisp').innerText = currencyFormatter.format(arv);
document.getElementById('profitDisp').innerText = currencyFormatter.format(profit);
document.getElementById('roiDisp').innerText = roi.toFixed(2) + '%';
document.getElementById('maoDisp').innerText = currencyFormatter.format(mao);
// Styling based on profitability
var profitElem = document.getElementById('profitDisp');
if (profit >= 0) {
profitElem.className = 'result-value highlight-positive';
} else {
profitElem.className = 'result-value highlight-negative';
}
}
Understanding Real Estate Rehab Costs
Accurately estimating repair costs is the single most critical skill for real estate investors, specifically those involved in "fixing and flipping" properties. A Rehab Calculator helps bridge the gap between a rough guess and a profitable investment strategy. Overestimating the After Repair Value (ARV) or underestimating the renovation budget are the two most common reasons flips fail.
How to Use This Calculator
This tool breaks down renovation expenses into major construction categories. Rather than guessing a lump sum, input estimates for specific trades (Roofing, HVAC, Kitchens, etc.).
Purchase Price: The amount you are paying to acquire the distressed property.
ARV (After Repair Value): The estimated market value of the home once all renovations are complete. Compare this with recently sold, renovated homes in the same neighborhood.
Contingency Budget: Unexpected issues always arise when opening walls. A healthy contingency of 10-20% protects your profit margin from unforeseen structural, electrical, or plumbing issues.
The 70% Rule Explained
Included in the results is a "70% Rule Max Offer." This is a standard rule of thumb used by investors to determine the Maximum Allowable Offer (MAO). The formula is:
The 30% margin is designed to cover holding costs, closing costs, realtor fees, and your profit. If your Total Investment (Purchase + Rehab) exceeds this number, the deal may be too risky unless the market is rapidly appreciating.
Common Rehab Cost Categories
When inspecting a potential property, pay close attention to the "big ticket" items:
HVAC & Systems: Replacing a furnace or A/C unit can cost thousands. Always check the age of the mechanicals.
Kitchen & Baths: These rooms sell houses. Budget for new cabinets, countertops (granite/quartz), and modern fixtures.
Roofing: A leaking roof can cause hidden mold and structural damage. Roof replacement is a high-priority budget item.
Permits: Do not forget the cost of city permits and the time delays associated with inspections.