Mortgage Calculator (National Average Property Tax & Insurance)

Property tax is the one input in a mortgage payment that varies most by location, from under 0.5% of assessed value in Hawaii and Alabama to close to 2% in New Jersey and Illinois. This calculator uses a single national number instead: 1.04%, the simple average of the effective property tax rate across all 50 states, computed directly from this platform's own state-by-state property tax table. That makes it the right tool for comparing a mortgage payment in the abstract, sizing up affordability before you know which state you'll buy in, or getting a first-pass number without picking a specific location.

If you already know the state where you're buying, use that state's dedicated mortgage calculator instead. A state-specific rate will get you closer to the real number, particularly in high-tax states like New Jersey, New Hampshire, and Connecticut or low-tax states like Hawaii and Alabama, where the gap between the state rate and this 1.04% national average is largest.

The principal and interest math, a fixed-rate loan amortized monthly over a 30-year term, is the same amortization engine used across every mortgage calculator on this platform, state-specific or not. Only the property tax assumption and the framing change.

1. Down payment and loan principal. The down payment percentage is applied to the home price; the remaining balance becomes the loan principal.
2. Principal and interest (P&I). The loan principal is amortized over 360 months (30 years):

$$\text{Payment} = P \times \frac{i(1+i)^{360}}{(1+i)^{360} - 1}$$

1. Property tax. Home price is multiplied by the 1.04% national average effective rate and divided by 12 for a monthly figure.
2. Insurance. A flat $125 monthly homeowners insurance estimate is added, the same placeholder used across this platform's mortgage calculator family.
3. Total PITI. Principal, interest, tax, and insurance are summed into the headline monthly payment.

Using the calculator's default inputs:

• Home Price: $380,000.00
• Down Payment: 20% ($76,000.00)
• Interest Rate: 6.5%
• Term: 360 months (30 years)

Step by step:

1. Loan principal: $380,000 minus $76,000 equals $304,000.00
2. Monthly principal and interest at 6.5% over 360 months: $1,921.49
3. National average property tax: $380,000 times 1.04% equals $3,952.00 per year, or $329.33 per month
4. Homeowners insurance estimate: $125.00 per month
5. Total monthly PITI: $1,921.49 plus $329.33 plus $125.00 equals $2,375.82
6. Total interest paid over the full 30-year term, summed across all 360 scheduled payments: $387,735.24

• Your actual state and county property tax rate. The 1.04% figure is a 50-state simple average, not a weighted-by-population average and not any single jurisdiction's real rate. States like New Jersey and Illinois run close to 1.9%; states like Hawaii and Alabama run under 0.5%. If your target state is known, switch to that state's dedicated calculator for a closer estimate.
• PMI for down payments under 20%. This calculator does not add private mortgage insurance, typically required when the down payment falls below 20% of the purchase price.
• HOA dues. Condos, townhomes, and many planned communities carry separate monthly homeowners association fees that this calculator does not include.
• Property tax exemptions. Homestead exemptions, senior freezes, veteran exemptions, and assessment caps vary by state and can lower the effective rate well below both the national average and the raw statutory rate.
• Closing costs and prepaid escrow. This tool models the ongoing monthly payment only, not the upfront cash needed to close.
• Rate type. The calculation assumes a fixed-rate loan; adjustable-rate mortgages (ARMs) reset the interest rate on a schedule this calculator does not model.

• Treating the national average as your local rate. A 1.04% assumption can understate a payment by hundreds of dollars a month in high-tax states and overstate it just as much in low-tax states. Use it for ballpark comparisons, not for a closing disclosure estimate.
• Forgetting PMI below 20% down. Lower down payments unlock homeownership sooner but usually add a PMI line item, sometimes $100 to $300 a month on a loan this size, that this calculator's output does not reflect.
• Ignoring HOA fees when comparing a condo to a single-family home. Two properties with identical PITI can have very different total monthly housing costs once HOA dues are added.
• Using a teaser ARM rate as if it were fixed for 30 years. Adjustable-rate loans can reset substantially higher after the initial fixed period; this calculator's fixed-rate math will understate long-run cost for an ARM.
• Skipping the state-specific calculator when you already know where you're buying. The national average exists for comparison and early-stage planning; once you know the state, a dedicated state calculator gets you a materially more accurate tax figure.

• Tax Foundation: Property Taxes by State (effective rate rankings).
• US Census Bureau: American Community Survey, property tax and home value data.
• Consumer Financial Protection Bureau: Regulation Z mortgage disclosure standards and PMI requirements under the Homeowners Protection Act.