Mortgage Payment Calculator
Calculate monthly mortgage payments including taxes and insurance
Fast, accurate calculations with clear results. Built for speed and ease of use.
Formula
Monthly Payment = P[r(1+r)^n]/[(1+r)^n-1]How to Use Mortgage Payment Calculator
- Provide your input values.
- Understand the calculation method shown.
- Get immediate and accurate results.
- Use the output for planning or analysis.
Examples
A mortgage payment uses the exact same amortisation formula as any other instalment loan, applied to a much larger balance over a much longer term, and the number this calculator returns is principal and interest only. Property tax and homeowners insurance, often collected through an escrow account, get added on top by your servicer and are not part of the P&I figure a mortgage calculator quotes.
The formula
M = P x [r(1+r)^n] / [(1+r)^n - 1]- M
- the monthly principal and interest payment
- P
- the loan amount, home price minus deposit
- r
- the monthly interest rate (annual rate / 12)
- n
- the total number of monthly payments (30 years = 360)
Worked example
A $350,000 home bought with a 10% deposit of $35,000 leaves a loan of $315,000, a 90% loan-to-value ratio. At 6.5% over 30 years, r = 0.065 / 12 = 0.0054167 and n = 360, giving (1.0054167)^360 = 6.99177, so M = 315000 x 0.0054167 x 6.99177 / 5.99177 = $1,991.02 a month in principal and interest alone.
What trips people up
- The quoted payment excludes tax, insurance, and any mortgage insurance required above roughly 80% LTV, so the amount that actually leaves your account each month is higher.
- A higher deposit lowers P directly and can also drop you into a lower LTV band, which sometimes removes the mortgage insurance requirement entirely.
- n has to be total payments, 360 for a 30 year term, not 30.
- Refinancing restarts the amortisation schedule, so most of the new payment goes to interest again for the first several years even if the rate is lower.
Frequently asked questions
- Why is my actual mortgage bill higher than the P&I number this calculator gives?
- Because property tax, homeowners insurance, and any mortgage insurance are usually collected alongside P&I through an escrow account, and none of those are part of the amortisation formula.
- What loan-to-value ratio removes the need for mortgage insurance?
- It varies by lender and loan type, but 80% LTV, a 20% deposit, is the common threshold below which conventional loans typically drop the mortgage insurance requirement.
- Does a bigger deposit always lower the monthly payment?
- Yes, directly, because it lowers P, the amount financed, and it can also lower the payment further by moving you into a better LTV band or removing mortgage insurance.
- How does refinancing affect the amortisation schedule?
- It replaces the old loan with a new one at a new rate and, usually, a new 30 or 15 year term, which restarts the schedule so early payments on the new loan go mostly to interest again.
- Why do two lenders quote different monthly payments for the same loan amount and rate?
- If P, r and n truly match, the P&I payment should match too. Differences usually come from what else is bundled into the quoted number, points, fees financed into the loan, or an estimated escrow amount.