What each term includes
PITI has four basic parts
The CFPB defines PITI as principal, interest, taxes, and insurance. Property tax and homeowners insurance may be collected through escrow with the mortgage payment.
PMI or other mortgage insurance is not one of the four letters, but it can still be part of the total amount collected by the lender or servicer.
Escrow is an account arrangement, not a new fee
A servicer can collect money for property tax and insurance, hold it in escrow, and pay those bills when due. The calculator divides the annual amounts by 12.
Actual escrow can include initial reserves, annual adjustments, or shortage payments, so a servicer statement can differ from simple division.
Why HOA is shown separately
HOA dues are usually paid to an association or manager, may not be collected by the mortgage servicer, and do not reduce mortgage principal. The page therefore keeps HOA outside PITI and escrow.