How this instrument works
PITI is shorthand for the four pieces that typically make up a homeowner's monthly mortgage bill: Principal, Interest, Taxes, and Insurance. The first two come straight from the loan itself — how much was borrowed, at what rate, over how many months. The last two are collected by the servicer on the lender's behalf and held in an escrow account, then paid out when the property tax bill and the insurance premium actually come due. A quote that only shows principal and interest is showing you roughly three-quarters of what most owners actually write a check for each month.
The math is deliberately split into pieces rather than one blended number, because each piece answers a different question and moves for a different reason. The loan payment is fixed by the note — it does not change unless the rate is adjustable or the loan is refinanced. The tax and insurance lines are simply the annual bill divided by twelve, and they move whenever the county reassesses the property or the insurer resets a premium, independent of anything happening with the mortgage itself.
Escrow accounts are not universal — some conventional buyers with enough equity pay tax and insurance bills directly instead — and where they are used, federal rules under RESPA cap what a servicer can collect: no more than one-twelfth of the anticipated annual total each month, plus up to a two-month cushion against shortfalls. This sheet does not model PMI, HOA dues, or an escrow cushion; it shows the four core pieces of the payment exactly, which is the number worth checking a lender's PITI quote against.
- Type the amount you are borrowing into 'Loan amount, $', then match 'Annual interest rate, %' to the note rate on your loan estimate.
- Set 'Loan term, years' — a shorter term raises the loan payment but cuts the total interest the loan will ever accrue.
- Add last year's bill under 'Annual property tax, $' and your policy premium under 'Annual homeowners insurance, $'.
- Read 'Principal + interest payment' for the loan alone, then compare it against 'Total monthly payment (PITI)' to see what escrow adds.
- Check the two escrow lines — 'Escrowed property tax, monthly' and 'Escrowed insurance, monthly' — against your actual bills before relying on the total.
Worked example — $300,000 borrowed at 7% for 30 years
Borrow $300,000 at 7% for 30 years and the loan formula alone gives a principal-and-interest payment of $1,995.91 a month — that is the figure most rate-shopping ads and pre-approval letters lead with, because it is the one number every lender's loan terms produce identically for the same loan.
Add a $3,600 annual property tax bill and a $1,200 annual homeowners insurance premium, and escrow adds $300.00 and $100.00 a month respectively, for a total monthly payment (PITI) of $2,395.91 — about $400 more than the loan payment by itself. That $400 gap is exactly the part a bare 'monthly payment' figure leaves out, and it is real money due to the servicer every month regardless of which number got advertised.
Questions
What does PITI actually stand for?
Principal, Interest, Taxes, and Insurance — the four line items an escrowed mortgage bill typically bundles into a single monthly withdrawal. Principal and interest come from the loan itself; taxes and insurance are collected in advance and paid out by the servicer when the actual bills come due.
Why is my total monthly payment higher than the loan payment alone?
Because two more line items — escrowed property tax and escrowed homeowners insurance — sit on top of the loan payment once a servicer collects and holds funds for them. Neither changes how much you owe on the loan; they just move the timing of two bills you would otherwise pay yourself in large, occasional lumps.
Does a higher property tax bill change my loan payment?
No. Raising 'Annual property tax, $' only changes the escrowed tax line and the total — the principal-and-interest figure comes from the borrowed amount, the rate, and the term alone, and never reacts to tax or insurance inputs, since those four formulas are kept entirely separate.
Why might a lender's PITI quote differ from this total?
Most commonly because the quote also folds in private mortgage insurance, HOA dues, or an escrow cushion required by law — none of which this sheet models. A lender's estimate can also use a projected tax bill after reassessment rather than last year's actual figure, which shifts the escrow lines without touching this arithmetic.
Is escrow required on every mortgage?
It depends on the loan program and how much equity is involved — some lenders require it, particularly on smaller down payments, while others let a borrower with sufficient equity pay tax and insurance bills directly. Either way the underlying tax and insurance costs are identical; escrow only changes who writes those checks and when.
How is the monthly escrow figure derived from my tax bill?
It is simply the annual bill divided by twelve, spreading one lump payment into equal monthly deposits so the servicer has the full amount ready when the tax authority or insurer is actually due to be paid. A reassessment or premium renewal changes next year's annual figure and, with it, the monthly deposit.
References
- CFPB — What is an escrow or impound account?
- CFPB — Limits on escrow collections for taxes and insurance
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.