Start with the arithmetic, not the story. A fixed nominal mortgage payment does not change. Its purchasing power does. If you owe a payment of $1,450 every month for 30 years, the lender receives $1,450 every month for 30 years. What changes is what $1,450 buys in year 20 compared with year 1.
This article builds a year-by-year ledger for two named paths. Path A assumes 0% annual inflation. Path B assumes 3% annual inflation. Both apply the same fixed nominal payment of $1,450 for 30 years. The only difference is the deflator. The result is definitional: if the price level rises and the nominal payment is frozen, the real payment falls by construction. No forecast is required to state that identity.
The 3% figure is a labeled input, not a prediction. The Federal Reserve’s December 2023 Summary of Economic Projections reported a median longer-run PCE inflation projection of 2.0 percent, with the caveat that longer-run projections represent each participant’s assessment of the value to which each variable would be expected to converge over time under appropriate monetary policy and in the absence of further shocks to the economy. That is a projection, not a commitment. The 3% path below is a sensitivity, and the article also shows 2% and 4% so you can see the result is a function of the chosen rate, not a property of mortgages.
Define the ledger before any numbers
Every table in this article uses the same columns. Year is the loan year, 1 through 30. Age is the borrower’s age at the start of that loan year, assuming the loan begins at age 35. Nominal payment is the contractual monthly amount, $1,450 in every year. Cumulative nominal paid is the sum of nominal payments through that year. Price index is the cumulative inflation factor, set to 1.000 in year 1. Real payment is the nominal payment divided by the price index, expressed in year-1 dollars. Cumulative real paid is the sum of real payments through that year.
The assumptions are stated once and held constant. The loan is a fixed-rate, fully amortizing 30-year mortgage with a fixed nominal monthly payment of $1,450. There is no escrow, no property tax, no homeowner’s insurance, no mortgage insurance, no HOA, no rate change, no refinance, and no extra principal. Inflation is applied annually at a constant rate. The payment side is shown only. The borrower’s nominal income and other nominal costs are not modeled, and the ledger does not claim a net gain.
Path A: 0% inflation
Under 0% inflation, the price index stays at 1.000 every year. The real payment equals the nominal payment every year. Cumulative real paid after 30 years is 360 × $1,450 = $522,000.
| Year | Age | Nominal payment | Cumulative nominal paid | Price index | Real payment (year-1 dollars) | Cumulative real paid |
|---|---|---|---|---|---|---|
| 1 | 35 | $1,450 | $17,400 | 1.000 | $1,450 | $17,400 |
| 10 | 44 | $1,450 | $174,000 | 1.000 | $1,450 | $174,000 |
| 20 | 54 | $1,450 | $348,000 | 1.000 | $1,450 | $348,000 |
| 30 | 64 | $1,450 | $522,000 | 1.000 | $1,450 | $522,000 |
The table is boring on purpose. With no inflation, there is no real erosion. The nominal and real columns are identical.
Path B: 3% constant inflation
Under 3% annual inflation, the price index in year n is (1.03)^(n−1). The real payment in year n is $1,450 ÷ (1.03)^(n−1). The nominal payment never changes. Only the deflator does.
| Year | Age | Nominal payment | Cumulative nominal paid | Price index | Real payment (year-1 dollars) | Cumulative real paid |
|---|---|---|---|---|---|---|
| 1 | 35 | $1,450 | $17,400 | 1.000 | $1,450 | $17,400 |
| 10 | 44 | $1,450 | $174,000 | 1.305 | $1,111 | $149,000 |
| 20 | 54 | $1,450 | $348,000 | 1.754 | $827 | $265,000 |
| 30 | 64 | $1,450 | $522,000 | 2.427 | $597 | $356,000 |
Read the last column against Path A. Under 0% inflation, cumulative real paid after 30 years is $522,000. Under 3% inflation, cumulative real paid is about $356,000. The gap is $166,000 in year-1 dollars. That gap is the arithmetic result of the deflator. It is not a claim about any lender, borrower, or contract.
The year-30 real payment is $597, not $1,450. The nominal check the borrower writes is still $1,450. The difference is what that check costs in year-1 purchasing power.
Sensitivity: 2% and 4%
The result is a function of the inflation rate you choose. Rerun the same formula at 2% and 4%.
| Inflation rate | Year-10 real payment | Year-20 real payment | Year-30 real payment | Cumulative real paid after 30 years |
|---|---|---|---|---|
| 0% | $1,450 | $1,450 | $1,450 | $522,000 |
| 2% | $1,186 | $970 | $793 | $393,000 |
| 3% | $1,111 | $827 | $597 | $356,000 |
| 4% | $1,041 | $706 | $447 | $324,000 |
The Fed’s December 2023 median longer-run PCE inflation projection of 2.0 percent sits near the low end of this strip. The 30-year inflation-indexed Treasury constant maturity yield was 3.31 percent on October 1, 2026, according to the Federal Reserve’s H.15 release, while the 30-year nominal Treasury constant maturity yield was 5.61 percent on the same date. That spread is not a clean market forecast of 30-year inflation; it reflects liquidity and term premia as well. It is one input among many, not a verdict.
What the ledger does not show
Inflation also raises the borrower’s nominal income and other nominal costs. A falling real mortgage payment is not a net gain by itself. If nominal wages rise at the same rate as prices, the real wage is unchanged, and the real mortgage payment falls relative to that wage. If nominal wages lag prices, the real burden of other costs rises. The ledger shows the payment side only and says so explicitly.
The exercise also does not model escrow, property taxes, homeowner’s insurance, mortgage insurance, HOA dues, ARM resets, or refinancing. Those items can rise with inflation or with local assessments, and they are not fixed in nominal terms. A fixed-rate, fully amortizing mortgage is one of the few household liabilities whose nominal cash cost is contractually frozen for the life of the loan. That structural feature is why the real-burden decline is larger and more mechanical than for a floating-rate or revolving balance. It is not a claim about any specific borrower.
Rebuild the table in a spreadsheet
You can verify every number above with one spreadsheet column. Set cell A1 to the nominal payment, $1,450. Set cell B1 to the annual inflation rate as a decimal, for example 0.03. In cell A2, enter the year number 1. In cell B2, enter the formula =$A$1/(1+$B$1)^(A2-1). Copy that formula down to year 30. The result in year n is the real payment in year-1 dollars.
To get cumulative real paid, add a column C with =SUM($B$2:B2) copied down. To get the price index, add a column D with =(1+$B$1)^(A2-1). If your result differs from the table above, the difference is traceable to the stated inflation rate or the base-year convention, not to hidden assumptions.
For a related exercise on how small, consistent contributions compound over long horizons, see What a Ten-Dollar Weekly Bump Actually Does to Your Retirement Number. The same ledger discipline applies: state the assumptions, show the year-by-year path, and let the reader rebuild the math.
FAQ
Does this mean inflation pays my mortgage?
No. It means a fixed nominal payment loses real value when the price level rises. Whether that is a net benefit depends on what happens to your nominal income and your other nominal costs, which this ledger does not model.
Is 3% the right inflation assumption?
There is no single right number. The Fed’s December 2023 median longer-run PCE inflation projection was 2.0 percent, but that is a projection under appropriate monetary policy and in the absence of further shocks, not a guarantee. The 3% path is a sensitivity. Rerun the table at 2% and 4% to see the range.
Why does the nominal payment never change?
Because the loan is fixed-rate and fully amortizing. The contract sets the nominal monthly payment for the life of the loan. The real payment changes only because the deflator changes.
What about escrow, taxes, and insurance?
They are not in this ledger. They can rise with inflation or with local assessments, and they are not fixed in nominal terms. The exercise isolates the fixed principal-and-interest payment.
Can I use this for an adjustable-rate mortgage?
No. An ARM’s nominal payment can change when the rate resets. The real-burden decline shown here depends on the nominal payment being contractually frozen.
Where does the $1,450 figure come from?
It is a hypothetical input chosen to make the arithmetic concrete. It is not a quote from any lender or contract.