Financial Guides
Understand how loans, mortgages, debt and interest actually work. Our guides explain the concepts behind the numbers so you can use LoanMathWorks calculators with greater context and confidence.
Start with the fundamentals
Mortgage payments involve more than a loan amount and interest rate. This guide explains the major pieces that can make up the amount homeowners pay each month.
How Mortgage Payments Are Calculated
Learn how principal and interest are calculated, why property taxes and homeowners insurance can affect the total monthly payment, and how PMI, HOA fees, rates and loan terms can change the numbers.
Read the guide →Mortgage Guides
Learn how mortgage payments, amortization and refinancing work.
How Mortgage Payments Are Calculated
Understand principal, interest, property taxes, insurance, PMI and other costs that can affect a monthly mortgage payment.
Read guide → AmortizationHow Loan Amortization Works
Learn why early payments contain more interest, how principal repayment increases over time and how an amortization schedule tracks the remaining balance.
Read guide → RefinancingWhen Does Refinancing Make Sense?
Learn how rates, closing costs, break-even time, remaining loan term and future plans can affect a refinance comparison.
Read guide →Auto Loan Guides
Understand vehicle affordability beyond the sticker price.
How Much Car Can I Afford?
Learn how income, monthly budget, debts, down payment, trade-in value, interest rates, insurance and other ownership costs can affect vehicle affordability.
Read guide → Loan TermsHow Loan Terms Affect Monthly Payments and Total Interest
See why extending an auto loan can lower the monthly payment while increasing the amount of time the balance remains outstanding.
Read guide → Early PayoffHow Extra Payments Reduce Loan Interest
Learn how additional principal payments can change payoff time and reduce future interest on many installment loans.
Read guide →Personal Loan & Debt Guides
Learn how lenders and borrowers evaluate debt, monthly payments and repayment terms.
What Is a Good Debt-to-Income Ratio?
Learn how DTI is calculated, which monthly debts are commonly included and why lenders may use this ratio when reviewing borrowing capacity.
Read guide → Debt RepaymentHow Extra Payments Reduce Loan Interest
Understand how paying principal ahead of schedule can reduce the remaining balance, shorten repayment and potentially lower interest.
Read guide → Loan TermsHow Loan Terms Affect Monthly Payments and Total Interest
Compare shorter and longer repayment periods and see why monthly affordability and lifetime cost can move in opposite directions.
Read guide →Debt & Interest Guides
Understand rates, APR, interest calculations and the long-term cost of borrowing.
APR vs. Interest Rate: What’s the Difference?
Learn what an interest rate represents, what APR may include and why the two percentages can differ when comparing loans.
Read guide → InterestSimple Interest vs. Compound Interest
Understand the difference between interest calculated from original principal and interest that can build on an accumulating balance.
Read guide → Interest SavingsHow Extra Payments Reduce Loan Interest
See why reducing principal earlier can lower the amount available for future interest to accumulate on.
Read guide → Repayment TermsHow Loan Terms Affect Monthly Payments and Total Interest
Learn why longer repayment periods generally lower monthly payments while increasing potential lifetime borrowing costs.
Read guide → AmortizationHow Loan Amortization Works
See how each payment is divided between interest and principal and why that allocation changes throughout repayment.
Read guide → DebtWhat Is a Good Debt-to-Income Ratio?
Understand how monthly debt obligations relate to gross income and why DTI is commonly considered in lending.
Read guide →Understand the concept, then run the numbers
LoanMathWorks is designed so our guides and calculators work together. Learn what a financial number means, then test different scenarios using your own assumptions.
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LoanMathWorks includes 20 free calculators covering mortgages, auto loans, personal loans, debt, APR and interest.