Estimate your Housing Choice Voucher payment and family share.
Household Income & Deductions
Total income before taxes from all family members.
Children under 18 or disabled adults (excluding head). $480 deduction each.
No
Yes
Head of household or spouse is 62+ or disabled. $400 deduction.
Unreimbursed medical (if elderly/disabled) or childcare costs.
Unit & Voucher Details
The maximum subsidy allowed by your local PHA for your bedroom size.
The full rent amount the landlord is charging.
PHA estimated cost for tenant-paid utilities.
Calculation Breakdown
Monthly Adjusted Income:$0.00
Total Tenant Payment (TTP):$0.00
Gross Rent (Rent + Utilities):$0.00
Housing Assistance Payment (HAP): What Section 8 pays landlord$0.00
Your Estimated Rent Portion: Amount you pay landlord$0.00
Utility Reimbursement: Payment to you for utilities$0.00
How the Section 8 Calculator Works
The Section 8 Housing Choice Voucher (HCV) program helps low-income families afford decent housing in the private market. This calculator helps estimate your financial responsibility based on the complex formulas used by Public Housing Agencies (PHAs) and HUD.
Key Terms Explained
Payment Standard: The maximum amount of assistance a PHA will pay for a unit. This is usually set between 90% and 110% of the local Fair Market Rent (FMR).
Total Tenant Payment (TTP): The minimum amount the family must contribute towards rent and utilities. By law, this is generally the highest of:
30% of the family's monthly adjusted income.
10% of the family's monthly gross income.
The welfare rent (in limited states) or a minimum rent (usually $50).
Gross Rent: The sum of the Contract Rent (what the landlord asks for) plus the Utility Allowance (estimated cost of tenant-paid utilities).
Housing Assistance Payment (HAP): The subsidy paid directly to the landlord by the housing authority.
The Calculation Logic
The rent calculation follows a specific hierarchy:
Determine Adjusted Income: We take your annual gross income and subtract deductions (like $480 per dependent and $400 for elderly/disabled households) to find your monthly adjusted capability.
Calculate TTP: We calculate 30% of your adjusted monthly income and 10% of your gross monthly income. Your TTP is the higher of these two numbers.
Compare Rent to Payment Standard:
If the Gross Rent is lower than the Payment Standard, the Housing Authority pays the Gross Rent minus your TTP.
If the Gross Rent is higher than the Payment Standard, you must pay your TTP plus the difference between the Gross Rent and the Payment Standard.
Affordability Check (The 40% Rule)
When you first move into a unit, you cannot pay more than 40% of your adjusted monthly income towards rent. If the unit is too expensive (rent significantly higher than the Payment Standard), the calculator will trigger a warning, as the PHA may not approve the lease.
function calculateSection8() {
// 1. Get Input Values
var annualIncome = parseFloat(document.getElementById('grossAnnualIncome').value) || 0;
var numDependents = parseFloat(document.getElementById('numDependents').value) || 0;
var elderlyStatus = document.getElementById('elderlyStatus').value;
var medicalExpenses = parseFloat(document.getElementById('medicalExpenses').value) || 0;
var paymentStandard = parseFloat(document.getElementById('paymentStandard').value) || 0;
var contractRent = parseFloat(document.getElementById('contractRent').value) || 0;
var utilityAllowance = parseFloat(document.getElementById('utilityAllowance').value) || 0;
// Validate inputs to prevent NaN or illogical results
if (paymentStandard < 0 || contractRent < 0) {
alert("Please enter valid positive numbers for rent and payment standards.");
return;
}
// 2. Calculate Deductions
var dependentDeduction = numDependents * 480;
var elderlyDeduction = (elderlyStatus === 'yes') ? 400 : 0;
// Medical/Childcare expenses exceeding 3% of annual income are typically deductible for elderly/disabled
// For this simple calculator, we will treat the input as the "Allowable Deduction Amount"
// To make it more accurate, usually: (Medical – 3% of Annual Income).
// We will assume the user entered the *allowable* amount or just subtract the raw number for simplicity as rules vary by specific type.
var totalDeductions = dependentDeduction + elderlyDeduction + medicalExpenses;
// 3. Calculate Income Metrics
var adjustedAnnualIncome = Math.max(0, annualIncome – totalDeductions);
var adjustedMonthlyIncome = adjustedAnnualIncome / 12;
var grossMonthlyIncome = annualIncome / 12;
// 4. Calculate Total Tenant Payment (TTP)
// Rule: Highest of 30% Adjusted Monthly OR 10% Gross Monthly
var ttpOption1 = adjustedMonthlyIncome * 0.30;
var ttpOption2 = grossMonthlyIncome * 0.10;
var minimumRent = 50; // Standard PHA minimum, varies but 50 is common
var ttp = Math.max(ttpOption1, ttpOption2, minimumRent);
// 5. Calculate Housing Logic
var grossRent = contractRent + utilityAllowance;
// Determine the lower of Payment Standard or Gross Rent used for subsidy calc
var lowerOfStandardOrGross = Math.min(paymentStandard, grossRent);
// Housing Assistance Payment (HAP) = LowerOf – TTP
var hap = lowerOfStandardOrGross – ttp;
if (hap < 0) hap = 0;
// Family Share (Total amount family pays for rent + utilities)
// Family Share = Gross Rent – HAP
var familyShare = grossRent – hap;
// Tenant Rent to Owner (Check written to landlord)
// Tenant Rent = Contract Rent – HAP
var tenantRentToOwner = contractRent – hap;
var utilityReimbursement = 0;
// Handle Utility Reimbursement (Negative Rent)
if (tenantRentToOwner 0) {
urRow.style.display = 'flex';
document.getElementById('displayReimbursement').innerHTML = fmt.format(utilityReimbursement);
} else {
urRow.style.display = 'none';
}
// 7. Affordability Check (40% Rule at Move-in)
// Family Share cannot exceed 40% of Adjusted Monthly Income
var affordabilityThreshold = adjustedMonthlyIncome * 0.40;
var warningBox = document.getElementById('affordabilityWarning');
if (familyShare > affordabilityThreshold && familyShare > 0) {
warningBox.style.display = 'block';
warningBox.innerHTML = "⚠️ Affordability Warning: Your estimated Family Share (" + fmt.format(familyShare) + ") is " + ((familyShare/adjustedMonthlyIncome)*100).toFixed(1) + "% of your adjusted monthly income. Section 8 rules typically forbid paying more than 40% (" + fmt.format(affordabilityThreshold) + ") when first moving into a unit. This unit may be too expensive for your voucher size.";
} else {
warningBox.style.display = 'none';
}
}