David Chen is a Certified Financial Analyst with over 10 years of experience in residential mortgage analytics and P&I modelling.
Use this free mortgage calculator principal and interest only to see your exact monthly P&I payment, total interest cost, and payoff date—taxes, insurance, and PMI excluded.
Mortgage Calculator Principal and Interest Only
Principal & Interest Formula
Monthly P&I: M = P × [ r(1+r)^n ] / [ (1+r)^n – 1 ]
Total Interest: (M × n) – P
Formula Sources: Investopedia | Excel PMT Docs
Variables
- P: Original loan amount.
- r: Monthly interest rate (annual rate ÷ 12).
- n: Total monthly payments (years × 12).
Related Calculators
- Mortgage Calculator with Taxes & Insurance
- Interest-Only Mortgage Calculator
- Bi-Weekly Extra Payment Calculator
- Mortgage Amortization Schedule
What Is a Principal and Interest Only Calculator?
It isolates the core loan repayment—principal reduction plus interest cost—excluding property taxes, homeowner’s insurance, PMI, or HOA fees. This is the figure most lenders quote first and is identical to the Excel PMT function.
How to Calculate P&I Only (Example)
- Enter the loan amount (e.g., $350,000).
- Input the annual interest rate (e.g., 6.0%).
- Set the term (e.g., 30 years).
- Click “Calculate” for instant monthly principal & interest.
Frequently Asked Questions (FAQ)
Does this include property taxes? No—only principal and interest. Add taxes and insurance separately for “PITI.”
Is the payment fixed for the entire term? Yes, with a fixed-rate loan the P&I amount never changes.
Can I export an amortization schedule? This widget gives summary totals; duplicate the formula in Excel to build a full table.
Why exclude escrows? Taxes and insurance vary by location and can change yearly; isolating P&I gives a consistent baseline for comparison.