Key facts
- Core formula
- M = P·r(1+r)^n / ((1+r)^n−1) for fixed-rate level payments
- P&I means
- Principal and interest only
- PITI means
- Principal, interest, taxes, insurance (+ often MI/HOA)
- Best first tool
- Mortgage Payment Calculator on this site
- Official shopping form
- CFPB Loan Estimate (TRID)
- FHA difference
- MIP (upfront + annual) instead of conventional PMI
- Not included in P&I
- Property tax, HOI, HOA, PMI/MIP, utilities
- Advice status
- Educational worksheet — not a loan offer
What a mortgage payment calculator actually computes
The Mortgage Payment Calculator estimates principal and interest (P&I) for a fixed-rate amortizing loan. It uses the standard level-payment identity with monthly rate r = APR/12/100 and n = years×12.
That number is the backbone of a house payment, but it is rarely the full amount you send to a servicer. Taxes, insurance, and mortgage insurance often sit in escrow.
Inputs: where real numbers come from
Replace demo defaults with documents:
| Input | Where to find it | Helper tool |
|---|---|---|
| Home price / loan amount | Purchase contract or Loan Estimate | P&I |
| Down payment % | Offer worksheet / gift letter plan | Down payment |
| Interest rate / APR | Rate lock or LE page 1 | Compare offers |
| Property tax | County assessor / prior tax bill | Property tax |
| Homeowners insurance | Insurance quote | PITI |
| PMI or FHA MIP | Lender quote / FHA schedule | PMI / FHA |
From P&I to full housing cost
After you have P&I, open the PITI Calculator and add annual taxes and insurance (÷12), optional MI, and HOA.
If you are considering low down payments, model FHA with MIP and conventional PMI as separate paths — they are not interchangeable products.
- Longer terms lower monthly P&I but can raise total interest
- Extra principal only helps if applied to principal — confirm with servicer
- Cash to close is separate: down payment + closing costs
Next calculators in the shopping path
Check capacity with DTI and affordability, cash needs with down payment and closing cost, and acceleration ideas with extra payment or biweekly.
Always prefer the figures on your official Loan Estimate when they differ from a website.
Related calculators
Human-labeled links into the CalculatorUSA calculator set—mortgage, pay, debt, loans, and more.
All calculators · Mortgage & home · Tax & pay · Debt payoff · Home
Sources & further reading
Also see methodology, accuracy & sources, and editorial policy.
FAQ
Is the mortgage payment calculator the same as my escrow payment? ▾
No. P&I is only principal and interest. Escrow often adds taxes and insurance (and sometimes MI). Use the PITI calculator for a fuller monthly housing estimate.
Where does the amortization formula come from? ▾
It is the standard fixed-rate level-payment identity used across the mortgage industry. Lenders may round differently; the Loan Estimate is authoritative for an offer.
Does FHA use PMI? ▾
FHA uses mortgage insurance premiums (UFMIP and annual MIP), which differ from conventional PMI. Use the FHA calculator for orientation and confirm current HUD schedules.
Can this site approve my loan? ▾
No. These tools are educational only and are not a pre-approval or credit decision.
What should I do after calculating P&I? ▾
Add taxes/insurance (PITI), check DTI/affordability, estimate cash to close, then compare written Loan Estimates from lenders.
Which official resources should I read? ▾
CFPB Owning a Home and Loan Estimate explainers, plus HUD materials if considering FHA.