A mortgage quote is only one part of the cost of owning a home. This mortgage payment comparison worksheet helps you estimate the full monthly amount for each loan, including principal, interest, property taxes, insurance, mortgage insurance, association fees, and planned extra payments. Use the same assumptions for every quote so you can compare loans fairly and see how changes in price, deposit, rate, or loan term affect your budget.
Overview
The monthly payment shown in a lender quote may include only principal and interest, or it may also include items collected into an escrow or similar account. Before comparing offers, identify exactly what each quoted payment contains. A lower advertised payment is not necessarily the lower-cost loan if it comes with a higher interest rate, larger lender fees, mortgage insurance, or a shorter introductory period.
Use this basic structure for a complete mortgage payment comparison:
- Principal: the portion of the payment that reduces the amount borrowed.
- Interest: the lender’s charge for providing the loan.
- Property taxes: the estimated local tax bill divided into monthly amounts, where applicable.
- Homeowners insurance: the estimated annual premium divided by 12.
- Mortgage insurance: a possible additional cost when the loan structure or deposit requires it.
- Association fees: homeowners association, condominium, or similar charges that are separate from the mortgage itself.
- Extra payment: any voluntary amount you plan to pay toward the loan each month.
Your total monthly housing cost is therefore different from the principal-and-interest figure alone. You should also keep one-time costs separate. Deposit or down payment, lender charges, legal or conveyancing fees, valuation fees, inspections, taxes, and other closing costs affect the cash needed to complete the purchase but do not usually belong in the monthly payment calculation. For a broader estimate, see the closing costs calculator guide.
How to estimate
Start by recording the same fields for every loan offer. A spreadsheet is useful because it lets you change one assumption at a time and compare the result.
- Calculate the loan amount. Subtract the deposit or down payment from the purchase price. Add any financed fees only if the lender’s offer permits and you intend to finance them.
- Record the interest rate and term. Note whether the rate is fixed, variable, adjustable, or fixed for only an initial period. Record the full repayment term and the length of any introductory rate.
- Estimate principal and interest. For a standard fully amortizing loan, a common formula is:
M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]. Here,Pis the loan amount,ris the periodic interest rate, andnis the total number of payments. If payments are monthly, divide the annual rate by 12 and multiply the years by 12. A lender or mortgage calculator can perform this calculation. - Add recurring housing costs. Divide annual property taxes and insurance by 12. Add the monthly mortgage insurance amount and association fee, if applicable.
- Separate optional overpayments. Show your required payment and your planned extra payment on separate lines. Confirm whether the loan permits overpayments and whether any conditions or charges apply.
- Compare the total. Review both the monthly total and the cash required at closing. Then compare the total interest over the planned holding period, not only the first payment.
A simple worksheet can use these columns:
| Item | Loan A | Loan B | Notes |
|---|---|---|---|
| Purchase price | Use the same property and price | ||
| Deposit or down payment | Record amount and percentage | ||
| Loan amount | Purchase price minus deposit, adjusted for financed fees | ||
| Rate and rate type | Note fixed or variable periods | ||
| Loan term | Record years and payment frequency | ||
| Principal and interest | Required payment only | ||
| Taxes and insurance | Use current estimates, then test changes | ||
| Mortgage insurance | Confirm how it is calculated and when it ends | ||
| Association fee | Check what services are included | ||
| Total required monthly cost | Add recurring items | ||
| Planned extra payment | Keep separate from the required payment | ||
| Cash needed at closing | Include deposit, taxes, and transaction fees |
Inputs and assumptions
The quality of the comparison depends on the inputs. Do not fill gaps with optimistic assumptions when a lender, insurer, tax authority, association, or property professional can provide a more specific figure.
Loan terms
Record the quoted rate, annual percentage rate or equivalent disclosure where available, repayment term, points or discount charges, arrangement fees, and any required products. Ask whether the rate is guaranteed, when it expires, and what happens after a fixed or introductory period. For variable-rate loans, test a higher payment rather than relying only on the initial figure.
Taxes and insurance
Property taxes can vary by location, assessment, exemptions, and changes to local charges. Insurance depends on the property, coverage, deductible, location, and insurer. Use a written estimate when possible, and allow for the fact that these costs may change. If the home is in a managed development, request the current association fee, payment schedule, and any known planned increases or special charges.
Mortgage insurance and lender fees
Mortgage insurance may be a monthly cost, an upfront charge, or part of the interest rate, depending on the market and loan structure. Confirm the amount, how long it may apply, and the conditions for ending it. Lender fees should be listed separately from government taxes, legal costs, inspections, and other transaction charges. A loan with a lower rate may require more upfront cash, so compare both short-term and longer-term costs.
Keep the comparison property-specific. A condominium, townhouse, or single-family home can have different maintenance and association costs. A professional inspection may also reveal repairs that affect your post-purchase budget; use the home inspection checklist before finalizing your assumptions.
Worked examples
Consider a hypothetical home priced at $300,000 with a $60,000 deposit. The starting loan amount is $240,000 before any financed charges. Assume, for illustration only, that one offer has a 30-year repayment term and a fixed rate of 6.00%, while a second offer has the same term and a fixed rate of 6.50%. These rates are examples, not a current market quote.
Using the standard amortisation formula, the principal-and-interest payment is approximately $1,439 per month for the first loan and $1,517 per month for the second, before taxes, insurance, mortgage insurance, association fees, or other costs. The difference is approximately $78 per month. Over time, the interest difference may be more significant than the monthly difference, but the exact result depends on how long you keep the loan and whether you refinance, sell, or make extra payments.
Now add the same hypothetical recurring costs to each offer:
- Property taxes: $300 per month
- Homeowners insurance: $125 per month
- Association fee: $75 per month
- Mortgage insurance: $0 in this illustration
Loan A would have an estimated required monthly housing cost of $1,939 ($1,439 plus $300, $125, and $75). Loan B would be approximately $2,017. If you plan to pay an additional $150 toward principal, record the planned outlay as $2,089 for Loan A and $2,167 for Loan B, while retaining the required payment separately.
Next, compare the upfront figures. If Loan A has a higher lender fee but a lower rate, calculate how many months of estimated savings are needed to recover that fee. This break-even view is more useful than choosing solely by the rate or advertised payment. Also compare any early repayment restrictions, rate-change risk, and cash reserves left after closing.
When to recalculate
Revisit the worksheet whenever an input changes. Recalculate when a lender issues a revised quote, your rate-lock period changes, the purchase price or deposit changes, or you consider a different loan term. Run a fresh comparison if property taxes, insurance, association fees, or mortgage insurance are updated.
Recalculate before making an offer if your expected closing costs reduce your emergency savings. Update the worksheet after an inspection identifies repairs, after an appraisal affects the financing, or when you compare a fixed-rate loan with a variable-rate alternative. The home affordability planning guide can help you test the result against your wider budget, while the rent versus buy calculator guide can help place the monthly ownership cost in context.
For a practical final check, save the latest worksheet with the date, source of each estimate, and assumptions used. Compare the required payment, realistic total housing cost, cash needed at closing, and likely cost over your planned ownership period. If a quote is unclear, ask the lender to identify every recurring and one-time charge before relying on it. A careful mortgage payment comparison does not predict every future expense, but it gives you a consistent method for deciding whether a loan fits your budget.
