Key Takeaway
Maximum LIHTC rent is calculated using the formula: (Area Median Income × Income Limit Percentage ÷ 12) − Utility Allowance = Maximum Gross Rent. The most common mistakes are using the wrong household size for the bedroom count, applying outdated utility allowances, and confusing gross rent with tenant-paid rent. This guide walks through each step with a worked Sacramento-area example.
What Is the Formula for Calculating Maximum LIHTC Rent?
The maximum allowable rent for a LIHTC unit is derived from 26 USC §42(g)(2) and is calculated as follows:
- Look up the Area Median Income (AMI) for your metropolitan statistical area (MSA) or non-metro county
- Apply the income limit percentage for your unit’s set-aside designation (e.g., 50%, 60%)
- Multiply by the imputed household size for the unit’s bedroom count
- Divide by 12 to get monthly income
- Multiply by 30% (the statutory rent burden threshold)
- Subtract the applicable utility allowance
The result is your maximum gross rent — the total of tenant-paid rent plus utility allowance. The tenant’s actual rent payment is the maximum gross rent minus the utility allowance.
Where Do You Find Current AMI Figures?
HUD publishes Area Median Income data annually, typically in March or April. The official source is HUD User’s Income Limits page. For LIHTC purposes, you need the Multifamily Tax Subsidy Project (MTSP) Income Limits, not the Section 8 income limits — they use different hold-harmless provisions.
To find your limits:
- Go to HUD User Income Limits
- Select the appropriate fiscal year
- Select your state and county or MSA
- Click “MTSP Income Limits” (not “Section 8 Income Limits”)
- The resulting table shows income limits by household size at various AMI percentages
Important: HUD applies “hold harmless” provisions to LIHTC income limits, meaning they cannot decrease from one year to the next. If your area’s AMI drops, the income limits remain at the prior year’s level. This is required by IRC §42(g)(2)(A) and protects both tenants and property cash flow.
What Is the Bedroom-to-Household-Size Mapping?
Under IRS Revenue Ruling 89-24, the imputed household size for a LIHTC unit is 1.5 persons per bedroom. This is a statutory mapping — it doesn’t change based on actual occupancy. You always use these numbers:
| Unit Type | Imputed Household Size |
|---|---|
| Studio / Efficiency (0 BR) | 1 person |
| 1 Bedroom | 1.5 persons |
| 2 Bedroom | 3 persons |
| 3 Bedroom | 4.5 persons |
| 4 Bedroom | 6 persons |
| 5 Bedroom | 7.5 persons |
For fractional household sizes (1.5, 4.5, 7.5), you interpolate between the income limits for the two whole-number household sizes. For a 1-bedroom unit with an imputed household size of 1.5, you average the 1-person and 2-person income limits.
What Are the Income Limit Percentages?
The income limit percentage is determined by your property’s Land Use Restriction Agreement (LURA) or Extended Use Agreement. Under IRC §42(g)(1), the two traditional minimum set-asides are:
- 20-50 test: At least 20% of units reserved for households at or below 50% AMI
- 40-60 test: At least 40% of units reserved for households at or below 60% AMI
Since the Consolidated Appropriations Act of 2018, a third option is available:
- Average Income Test: Units can be designated at 20%, 30%, 40%, 50%, 60%, 70%, or 80% AMI, as long as the average across all restricted units does not exceed 60% AMI
The Average Income Test provides significant flexibility for mixed-income communities. A property could have units at 30% AMI alongside units at 80% AMI — as long as the designations average to 60% or below.
| AMI Designation | Target Population | Available Under |
|---|---|---|
| 20% AMI | Extremely low-income | Average Income Test |
| 30% AMI | Extremely low-income | Average Income Test |
| 40% AMI | Very low-income | Average Income Test |
| 50% AMI | Very low-income | 20-50 Test, Average Income Test |
| 60% AMI | Low-income | 40-60 Test, Average Income Test |
| 70% AMI | Low-income (workforce) | Average Income Test |
| 80% AMI | Moderate-income | Average Income Test |
How Do Utility Allowances Work in LIHTC Rent Calculations?
Under Treasury Regulation §1.42-10, the utility allowance is deducted from maximum gross rent to determine the maximum tenant-paid rent. The utility allowance represents the estimated monthly cost of tenant-paid utilities and must include:
- Heating and cooling
- Cooking fuel
- Hot water
- Electricity (lighting, appliances)
- Water and sewer (if tenant-paid)
- Trash removal (if tenant-paid)
If the landlord pays all utilities, the utility allowance is $0, and maximum gross rent equals maximum tenant-paid rent.
Utility allowances can come from several sources, depending on your property type:
| Source | When to Use | Update Frequency |
|---|---|---|
| Local Public Housing Authority (PHA) | Default for most LIHTC properties | Annually (typically) |
| HUD Utility Schedule Model (HUSM) | Optional alternative | When updated by HUD |
| Utility company estimate | When approved by HFA | Varies |
| Energy consumption model (ASHRAE) | For newer energy-efficient buildings | Per engineering analysis |
| Actual utility cost study | For properties with 12+ months of data | Annually |
According to IRS Notice 2009-44, properties that use an energy consumption model or actual cost study can often achieve lower utility allowances, resulting in higher maximum tenant-paid rent. This is especially relevant for new construction with modern HVAC systems.
Worked Example: Sacramento MSA, 2-Bedroom at 60% AMI
Let’s walk through a complete calculation using the Sacramento-Roseville-Folsom MSA as an example. These are illustrative figures based on recent HUD-published limits:
Step 1: Look Up the AMI Income Limit
From HUD’s MTSP Income Limits for Sacramento-Roseville-Folsom MSA:
- 60% AMI for a 3-person household: $47,520
(We use 3-person because a 2-bedroom unit has an imputed household size of 3.)
Step 2: Calculate Monthly Income
$47,520 ÷ 12 = $3,960 per month
Step 3: Calculate Maximum Gross Rent (30% of Monthly Income)
$3,960 × 0.30 = $1,188 maximum gross rent
Step 4: Subtract the Utility Allowance
Sacramento Housing and Redevelopment Agency (SHRA) utility allowance for a 2-bedroom unit with gas heating and cooking: $142
$1,188 − $142 = $1,046 maximum tenant-paid rent
Summary
| Component | Amount |
|---|---|
| 60% AMI for 3-person household | $47,520/year |
| Monthly income | $3,960 |
| Maximum gross rent (30%) | $1,188 |
| Utility allowance (2BR, gas heat) | −$142 |
| Maximum tenant-paid rent | $1,046 |
LIHTC Rent Limits by Bedroom Count (Sacramento MSA Example)
Here’s a complete rent limit schedule at multiple AMI levels for the Sacramento-Roseville-Folsom MSA, before utility allowance deductions:
| AMI Level | Studio | 1 BR | 2 BR | 3 BR | 4 BR |
|---|---|---|---|---|---|
| 30% AMI | $330 | $371 | $594 | $730 | $856 |
| 40% AMI | $440 | $495 | $792 | $974 | $1,141 |
| 50% AMI | $550 | $619 | $990 | $1,217 | $1,427 |
| 60% AMI | $660 | $743 | $1,188 | $1,461 | $1,712 |
| 70% AMI | $770 | $866 | $1,386 | $1,704 | $1,997 |
| 80% AMI | $880 | $990 | $1,584 | $1,948 | $2,283 |
Note: These are maximum gross rent figures (before utility allowance deduction). Actual maximum tenant-paid rent will be lower after subtracting the applicable utility allowance. Figures are illustrative based on recent published limits.
What Are the Most Common LIHTC Rent Calculation Mistakes?
After reviewing thousands of compliance files, these are the errors that generate the most IRS Form 8823 findings:
1. Using the Wrong Household Size
The most common mistake. Compliance officers sometimes use the actual household size instead of the imputed household size (1.5 per bedroom). A family of 5 in a 2-bedroom unit still uses the 3-person income limit for rent calculation — not the 5-person limit. Actual household size matters for income qualification; imputed household size matters for rent calculation.
2. Using Outdated Utility Allowances
Utility allowances must be updated when new schedules are published, typically annually. Properties that fail to update when their PHA publishes new allowances risk overcharging tenants — a noncompliance event. According to Treasury Regulation §1.42-10(c), the new utility allowance must be used for all rent determinations effective 90 days after the PHA publishes the updated schedule.
3. Confusing Section 8 Income Limits with MTSP Income Limits
HUD publishes separate income limit tables for Section 8 and for LIHTC (MTSP). The numbers are often different because of different hold-harmless provisions. Using Section 8 limits for LIHTC rent calculation can result in either overcharging or undercharging tenants.
4. Not Interpolating for Fractional Household Sizes
For a 1-bedroom unit (1.5-person imputed household), you must average the 1-person and 2-person income limits. Simply using the 1-person or 2-person limit alone is incorrect and will produce the wrong maximum rent.
5. Applying New AMI Limits Before the Effective Date
New HUD income limits take effect 45 days after publication. Applying them early (or late) results in incorrect rent calculations for certifications during the transition window.
How Does the Average Income Test Affect Rent Calculations?
Properties using the Average Income Test (IRC §42(g)(1)(C)) can designate individual units at AMI levels from 20% to 80%. The rent calculation formula is the same — you just apply the designated AMI percentage for that specific unit. The critical compliance requirement is that the average of all designated percentages across all restricted units must not exceed 60% AMI.
If a unit’s designation changes (for example, from 60% to 50% AMI to bring the average down), the maximum rent for that unit changes immediately. This creates operational complexity — our free Rent Limit Calculator handles Average Income Test scenarios automatically and flags when a redesignation would affect the property-wide average.
How Will HOTMA Change LIHTC Rent Calculations in 2027?
HOTMA doesn’t change the rent calculation formula itself, but it changes the inputs. Specifically, the HOTMA asset and income changes effective January 1, 2027 may cause some tenants’ calculated income to decrease (due to retirement account exclusions), which could affect whether they remain income-qualified — but it does not change the AMI-based rent limits. For a full analysis of HOTMA’s LIHTC provisions, see our HOTMA 2027 LIHTC guide.
Use the Free LIHTC Rent Limit Calculator
Manually calculating rent limits is error-prone, especially when interpolating fractional household sizes, applying updated utility allowances, and managing Average Income Test designations. Our free Rent Limit Calculator pulls current HUD MTSP income limits, applies the correct bedroom-to-household-size mapping, and deducts your applicable utility allowance to produce an accurate maximum tenant-paid rent.
Have a question about a specific rent calculation scenario? Ask our AI Compliance Advisor — it handles AMI lookups, utility allowance questions, and Average Income Test math.