How to Use
Enter the amount you plan to borrow (not the full purchase price).
Optionally add a down payment to reduce the financed principal.
Input the annual interest rate as a percentage (e.g. 6.5 for 6.5%).
Set the loan term in years, such as 15 or 30.
Click Calculate to generate your payment breakdown and amortization table.
Precision And Rounding Notes
Calculations use standard floating point arithmetic which may result in minor rounding differences of a few cents in the final payment or total interest. The amortization table displays the first 12 months in detail before summarizing subsequent years to maintain readability. All figures are estimates based on the inputs provided and do not account for variable rates or lender-specific fee structures.
Supported Input Groupings
The calculator groups financial inputs into four distinct categories: Loan Amount, Down Payment, Interest Rate, and Term. The Loan Amount and Down Payment combine to determine the Principal balance. The Interest Rate is converted from an annual percentage to a monthly decimal for the formula. The Term is converted from years to total monthly payments. This grouping ensures the formula M = P x [r(1+r)^n] / [(1+r)^n − 1] applies correctly to fixed-rate scenarios without requiring manual unit conversion by the user.
Worked Calculation Example
- Input a loan amount of 300,000 with a 20,000 down payment, resulting in a principal of 280,000.
- Enter an annual interest rate of 6.5%, which converts to a monthly rate of approximately 0.005417.
- Set the term to 30 years, creating a total of 360 monthly payments.
- The formula calculates a monthly payment of 1,768.27.
- Over the full term, the total interest paid is 354,577.20, making the total cost 634,577.20.
Key Features
Monthly Payment Engine
Derives exact monthly obligations using principal, rate, and term inputs without server interaction.
12-Month Detail Schedule
Displays granular monthly breakdowns for the first year followed by annual summaries of balance shifts.
Principal Interest Visualization
Stacked bar charts illustrate the annual ratio of principal repayment versus interest costs.
PDF Loan Summary Export
Generates a formatted document containing all calculation results for offline review or sharing.
Local Data Processing
Executes all financial logic within the browser to ensure no sensitive loan data transmits externally.
Privacy
All mortgage calculations run entirely in your browser using JavaScript. No loan amounts, rates, or personal data are transmitted to any server.
Frequently Asked Questions
What Is An Amortization Schedule?
It breaks each payment into its principal and interest portions alongside the remaining balance. Early in the loan most of each payment covers interest; later payments shift heavily toward principal reduction. The tool displays the first 12 months in detail before summarizing the rest annually.
Does This Include Taxes And Insurance?
No. The calculator covers principal and interest only. Your actual monthly housing cost will also include property taxes, homeowner's insurance, and possibly private mortgage insurance.
Can I Use This For Refinancing?
Enter your remaining balance as the loan amount, the new interest rate, and the new term length. The output lets you compare the refinanced payment against your current one. All calculations happen locally in your browser to keep your financial data private.
Why Is Total Interest So High On A 30 Year Mortgage?
Interest compounds on a large balance over many years, causing the total cost to grow significantly. At 7% for 30 years, total payments roughly double the original principal. Shorter terms cut total interest substantially but raise the monthly payment.