Finance calculators

Mortgage Comparison Calculator

Updated Aug 19, 2026 By Jehan Wadia
Rate Formulas
Loan Amount (applies to both loans)
Enter between $1,000 and $10,000,000. Formatted with commas automatically.
$50,000 $360,000 $2,000,000
Loan 1
Shown in the results table, chart legend and schedule.
Use the − / + buttons to step by 0.125%.
Net financed principal: $360,000.00
Loan 2
Shown in the results table, chart legend and schedule.
Use the − / + buttons to step by 0.125%.
Net financed principal: $360,000.00
Side-by-Side Comparison
Comparison of monthly and lifetime costs for Loan 1 and Loan 2.
Metric Loan 1 Loan 2
Monthly P&I $0.00 $0.00
Monthly Difference
Total Interest Paid $0.00 $0.00
Total Principal Paid $0.00 $0.00
Total P&I Paid (lifetime cost) $0.00 $0.00
Total Difference
Step-by-Step Solution
Visual Comparison
Monthly P&I Payment

Lifetime Cost Breakdown


Remaining Balance Over Time

Loan 1 Loan 2
Amortization Schedule

Introduction

This Mortgage Comparison Calculator lets you put two home loans side by side and see which one costs less. Enter a loan amount, then set the interest rate, loan term, and down payment for each loan. The calculator shows you the monthly payment, the total interest, and the full lifetime cost for both.

Picking a mortgage is a big choice. A 30-year loan gives you a smaller monthly payment, but you pay more interest over time. A 15-year loan costs more each month, but you own your home sooner and save a lot of interest. Even a small rate change, like 0.125%, can shift your cost by thousands of dollars.

You will see the math step by step, so you know exactly where each number comes from. Charts compare the payments and show how your balance drops each year. You can also open a full amortization schedule to view every payment, month by month or year by year.

Use it to compare loan offers, test different terms, or check how a bigger down payment changes your payment. All results update as you type, and nothing is saved or shared. If you only need numbers for one loan, the standard Mortgage Calculator is a faster starting point.

How to use our Mortgage Comparison Calculator

Enter one loan amount, then set the rate, term, and down payment for two different mortgage options. The calculator shows the monthly principal and interest payment, total interest, total cost, a step-by-step solution, charts, and a side-by-side amortization schedule so you can see which loan is cheaper.

Purchase Price / Loan Amount: Type the home price or amount you want to borrow. This same amount is used for both loans. Enter $1,000 to $10,000,000. Commas are added for you. Not sure what price fits your income? Check the Home Affordability Calculator first.

Adjust Loan Amount (slider): Drag the slider to change the loan amount fast. It moves in $5,000 steps and updates the box above it.

Loan 1 Label and Loan 2 Label: Give each loan a short name, like "30-Year Fixed" or "Bank Offer." The names show up in the results table, charts, and schedule. This is optional.

Interest Rate (Loan 1 and Loan 2): Type the yearly interest rate for each loan, up to three decimals. Use the minus and plus buttons to move the rate by 0.125% at a time. To see how quoted rates translate into cost, try the Mortgage Rate Calculator or the APR Calculator.

Loan Term (Loan 1 and Loan 2): Pick how many years you will pay the loan, from 10 to 40 years. Shorter terms mean higher payments but less interest.

Down Payment Mode (Dollar or Percent): Choose "Dollar ($)" to enter a cash amount, or "Percent (%)" to enter a share of the price. You can set a different mode for each loan.

Down Payment (Loan 1 and Loan 2): Enter your down payment. It is taken off the loan amount, and the hint below shows the net financed principal. Leave it at 0 if you have none. A smaller down payment usually raises your loan-to-value ratio and can trigger mortgage insurance.

Calculate button: Click it to update the results. Results also refresh as you type, so use this to check your final numbers.

Reset button: Click it to clear your changes and go back to the starting example values.

Show Amortization Schedule: Click to open a full payment table for both loans, then choose "Monthly view" or "Yearly view" to see each payment split into principal, interest, and remaining balance. For a deeper single-loan breakdown, use the Mortgage Amortization Calculator.

Compare Two Mortgages Side by Side

A mortgage is a loan you use to buy a home. You pay it back every month for many years. Two loans can look close on paper but cost very different amounts. This mortgage comparison tool puts two loan offers next to each other so you can see which one really costs less. For non-housing debt, the Loan Comparison Calculator works the same way.

What Changes the Cost of a Home Loan

  • Loan amount (principal): the money you borrow after your down payment.
  • Interest rate: the yearly price the lender charges. Even a small change, like 0.125%, moves your payment. See the total effect with the Mortgage Interest Calculator.
  • Loan term: how many years you pay. A shorter term means a bigger monthly payment but much less interest.
  • Down payment: cash you pay up front. More cash down means a smaller loan and lower interest.

Monthly Payment vs. Total Cost

These are two different things. A 30-year loan has a smaller monthly payment, so it is easier on your budget each month. But you pay for twice as long, so the total interest can be tens of thousands of dollars higher. A 15-year loan costs more each month, yet you often pay far less interest and own the home free and clear sooner. Look at both numbers before you choose, and check your debt-to-income ratio to make sure the higher payment still fits.

How the Payment Is Figured Out

Your monthly principal and interest (P&I) payment stays the same on a fixed-rate loan. The yearly rate is split into 12 to get a monthly rate, and the years are turned into a number of monthly payments. The math spreads the loan over that time so the balance hits zero on the last payment. The same formula powers our general Loan Payment Calculator.

What an Amortization Schedule Shows

Amortization is how each payment splits between interest and principal. In the early years, most of your money goes to interest and the balance drops slowly. Later, more goes to principal and the balance falls fast. A shorter loan or a lower rate flips that mix in your favor sooner. Adding money to each payment speeds this up a lot, which you can test with the Mortgage Extra Payment Calculator, the Biweekly Mortgage Calculator, or the Mortgage Payoff Calculator.

The Break-Even Point

If one loan costs more per month but less overall, there is a month where the two loans have cost you the same total. After that month, the cheaper loan pulls ahead and keeps saving you money. Knowing this helps if you might sell or refinance before that date.

Keep in Mind

These numbers cover principal and interest only. Your real monthly bill may also include property taxes, homeowners insurance, mortgage insurance (PMI), and HOA dues — the full PITI payment. Closing costs, points, and lender fees are not included either, so ask each lender for the APR and a Loan Estimate to compare the full picture. If you are weighing government-backed options, compare an FHA loan, a VA loan, or a jumbo loan against a conventional quote — and if you are still deciding whether to buy at all, run the numbers in the Rent vs Buy Calculator.


Formulas used

Net financed principal
P = \text{Loan Amount} - \text{Down Payment}
Down payment from percent
D = \text{Loan Amount} \times \frac{d\%}{100}
Monthly interest rate
r = \frac{\text{annual rate}\%}{100 \times 12}
Total number of monthly payments
n = \text{years} \times 12
Monthly principal & interest payment
M = P \times \frac{r(1+r)^{n}}{(1+r)^{n}-1} \quad (r>0), \qquad M = \frac{P}{n} \quad (r=0)
Total principal & interest paid
T = M \times n
Total interest paid
I = T - P
Amortization per period and comparison differences
\begin{aligned} I_k &= B_{k-1} \times r, \quad P_k = M - I_k, \quad B_k = B_{k-1} - P_k \\ \Delta_{\text{monthly}} &= M_1 - M_2, \quad \Delta_{\text{lifetime}} = T_1 - T_2 \end{aligned}

Frequently asked questions

Why does the calculator use one loan amount for both loans?

It keeps the test fair. When both loans start from the same home price, any difference in cost comes from the rate, term, or down payment — not from borrowing a different amount.

If you want to compare two different prices or two different loan sizes, change the down payment on one loan. That lowers the financed principal for that side only.

What does P&I mean in the results?

P&I stands for principal and interest. Principal is the money you borrowed. Interest is what the lender charges you to borrow it.

P&I is only part of your real bill. Property taxes, home insurance, PMI, and HOA fees are added on top by your lender.

Can I compare two loans with the same term but different rates?

Yes. Set both terms to 30 years, then enter one rate for Loan 1 and another for Loan 2. This is the best way to see what a rate quote is really worth.

Use the minus and plus buttons to step by 0.125%, which is how most lenders quote rate changes.

How much does a 0.125% rate difference actually save?

On a $360,000 loan over 30 years, it is usually about $25 to $30 per month. Over the full term that adds up to roughly $9,000 to $11,000 in interest.

Enter your own numbers and click the plus button once to see your exact savings.

What is the break-even month in the summary?

It is the month when both loans have cost you the same total cash. Before that month, the cheaper monthly loan is ahead. After it, the loan with less total interest is ahead.

This matters if you plan to sell or refinance. If you move before break-even, the lower monthly payment may be the better pick.

Why is the total principal different between my two loans?

Because you entered different down payments. The down payment is subtracted from the loan amount, so a bigger down payment means less principal to repay.

If both down payments are the same, the total principal will match on both sides.

Does the calculator include taxes, insurance, or PMI?

No. It shows principal and interest only. Your real payment can be several hundred dollars higher each month once escrow items are added.

Add taxes and insurance separately, or use a PITI calculator, to see your true monthly cost.

Are closing costs, points, or lender fees included?

No. The tool compares payment and interest only. A lender offering a lower rate may charge points or higher fees to get there.

Ask each lender for a Loan Estimate and compare the APR too, so fees are part of your decision.

Can I use this for an adjustable-rate mortgage (ARM)?

Only as a rough guide. The math assumes a fixed rate for the whole term, so an ARM after the fixed period will not match.

You can enter the ARM's starting rate on one side and a fixed rate on the other to compare the early years.

How do I switch the down payment between dollars and percent?

Click the Dollar ($) or Percent (%) button above the down payment box. The value converts for you automatically.

Each loan has its own switch, so you can use dollars on one side and percent on the other.

What is net financed principal?

It is the loan amount minus your down payment. That is the number the payment math actually uses.

Example: a $360,000 price with a $60,000 down payment gives a net financed principal of $300,000.

Why is my 15-year payment so much higher than my 30-year payment?

You are paying off the same balance in half the time. The payment is not double, though, because you also pay far less interest.

The trade-off is worth checking: higher monthly cost now, much lower lifetime cost later.

Can I compare loans with different terms, like 20 vs 30 years?

Yes. Pick any term from 10 to 40 years for each loan. They do not have to match.

The balance chart will show one loan reaching zero earlier than the other.

Why does the last payment in the schedule look different?

The final payment is adjusted so the balance lands exactly on zero. Rounding over hundreds of months leaves a few cents, and the last row absorbs it.

Your lender does the same thing on the real loan.

What is the difference between the monthly view and yearly view?

Monthly view lists every single payment. Yearly view groups 12 payments together and shows the balance at the end of each year.

Use yearly view for a quick overview and monthly view when you need exact numbers for one payment.

Can I enter a 0% interest rate?

Yes. The calculator handles it by simply dividing the principal by the number of months. Total interest will be $0.

This is useful for family loans or seller financing with no interest.

Which loan should I pick if one is cheaper monthly and the other is cheaper overall?

It depends on your budget and your plans. Pick the lower monthly payment if cash flow is tight or you may move soon.

Pick the lower total cost if you can afford the higher payment and plan to stay past the break-even month.

Does a bigger down payment always save me money?

It lowers your loan, your payment, and your total interest. It can also remove PMI once you reach 20% down.

But do not drain your savings. Keep an emergency fund and money for moving and repair costs.

Can I add extra monthly payments in this tool?

No. This calculator compares two loans on their normal payment schedules.

To test extra payments, use an extra payment or payoff calculator, then bring those results back here to compare.

Is my information saved or sent anywhere?

No. All math runs in your browser. Nothing is stored, shared, or sent to a server.

Refreshing the page clears everything and returns the example values.

Why don't my numbers match my lender's quote exactly?

Lenders often include taxes, insurance, PMI, or HOA dues in the payment they quote. This tool shows principal and interest only.

Small gaps can also come from rounding or a slightly different rate on your final loan documents.

What does the remaining balance chart tell me?

It shows how fast each loan is paid down year by year. A steeper line means you build equity faster.

Shorter terms and lower rates push the line down quicker, which helps if you want to sell or refinance sooner.