Mortgage Comparison Calculator

Enter two mortgage offers and instantly see which costs less over the full loan life, with balance milestones and a term-by-term interest comparison.

⚖️ Mortgage Comparison Calculator

Option A

Loan Amount (A)$400,000
$
$50K$2M
Interest Rate (A)6.50%
%
0.5%15%
Loan Term (A)30 yrs
yrs
5 yrs30 yrs

Option B

Loan Amount (B)$400,000
$
$50K$2M
Interest Rate (B)7.00%
%
0.5%15%
Loan Term (B)30 yrs
yrs
5 yrs30 yrs
Loan Amount$350,000
$
$50K$2M
Annual Interest Rate6.75%
%
0.5%15%

Compares 15, 20, and 30-year terms at the same rate and amount.

Option A Monthly
—
Option B Monthly
—
Option A Total Cost
—
Option B Total Cost
—
Verdict
—
Monthly Difference
—
30-Year Monthly
—
15-Year Monthly
—
20-Year Monthly
—
15-yr Interest Saved
—

⚖️ What is a Mortgage Comparison Calculator?

A mortgage comparison calculator is a tool that places two or more mortgage scenarios side by side so you can evaluate total cost, monthly payment, and equity buildup at the same time. Rather than calculating each loan separately and manually comparing the numbers, this calculator computes both scenarios simultaneously and displays a direct comparison table. It eliminates the arithmetic errors that come from switching between tabs or writing down numbers from different tools.

The Loan Compare mode is most useful when you have received proposals from two different lenders and want to know which offer actually costs less over the life of the loan. A lower interest rate does not always win, because a lower rate on a longer term or on a larger loan amount can produce a higher total cost than a slightly higher rate on a shorter term. This calculator shows total paid (principal plus interest) for both options, which is the definitive comparison metric. The balance milestone rows also show remaining balances at years 5, 10, 15, and 20, which is critical for borrowers who plan to sell or refinance before the loan matures.

The Term Compare mode answers the question every first-time borrower faces: 15-year, 20-year, or 30-year? The three terms are shown in a single table with monthly payment, total interest, total paid, and the interest savings relative to the 30-year baseline. The key insight is always the same: shorter terms cost far less in total interest but require a meaningfully higher monthly payment. A common misconception is that the 30-year is obviously better because the lower payment lets you invest the difference. In practice, the required return on that invested difference to break even on the 30-year choice is often higher than what most investors consistently achieve after taxes.

Both modes use the standard fixed-rate amortization formula, which is the same formula used by every US mortgage lender for conventional loans. Results appear instantly as you move any slider, making it easy to test dozens of scenarios in seconds without clicking Calculate each time.

📐 Formula

M  =  P × r(1 + r)n ÷ [(1 + r)n − 1]
M = monthly payment
P = loan principal (amount borrowed)
r = monthly interest rate = annual rate ÷ 12 ÷ 100
n = total number of payments = term years × 12
Balance at year y: Bᵧ = P×(1+r)12y − M×[(1+r)12y−1]÷r
Example: $400,000 at 6.5% for 30 yrs: r = 0.005417, n = 360, M = $2,529/month. Total interest = $510,440.

📖 How to Use This Calculator

Steps

1
Choose your comparison mode. Select Loan Compare to compare two specific mortgage offers with different amounts, rates, or terms, or select Term Compare to see 15, 20, and 30-year options for a single loan side by side.
2
Enter loan details for both options. For Loan Compare mode, fill in the loan amount, interest rate, and term for both Option A and Option B. Defaults are pre-filled so results appear immediately on page load.
3
Read the comparison table. The table shows monthly payment, total interest, total paid, and remaining balance at key year milestones. The summary boxes highlight the winner by total cost and the monthly payment difference between options.
4
Switch to Term Compare for a single loan. In Term Compare mode, enter one loan amount and one interest rate. The calculator instantly shows 15, 20, and 30-year side by side with interest saved versus the 30-year baseline for each shorter term.

💡 Example Calculations

Example 1 — Two Lender Offers at Different Rates

Option A: $400,000 at 6.5% for 30 years vs Option B: $400,000 at 7.0% for 30 years

1
Option A: r = 0.005417, n = 360. Monthly payment = $2,528. Total interest = $510,178.
2
Option B: r = 0.005833, n = 360. Monthly payment = $2,661. Total interest = $558,036.
3
Option A is cheaper: $47,858 lower total interest and $133/month lower payment. Balance at year 10: Option A = $339,105 vs Option B = $343,250, showing faster equity buildup at the lower rate.
Option A saves $47,858 in total interest over 30 years.
Try this example →

Example 2 — Same Rate, Different Terms (30-Year vs 15-Year)

$400,000 at 6.5%: 30-year vs 15-year comparison

1
30-year monthly = $2,528. Total interest = $510,178. Total paid = $910,178.
2
15-year: r = 0.005417, n = 180. Monthly = $3,484. Total interest = $227,197. Total paid = $627,197.
3
The 15-year saves $282,981 in interest at a cost of $956 more per month. Break-even: if you invest the $956/month difference at above 7% annually, the 30-year choice can win. Below 7%, the 15-year is better.
15-year saves $282,981 in interest | Extra cost: $956/month
Try this example →

Example 3 — 15 vs 20 vs 30 Years on $350K at 6.75%

$350,000 at 6.75%, comparing all three standard terms

1
30-year: Monthly = $2,270/month. Total interest = $467,234. Total paid = $817,234.
2
20-year: Monthly = $2,661/month ($391 more). Total interest = $288,706. Interest saved vs 30-yr = $178,528.
3
15-year: Monthly = $3,097/month ($827 more). Total interest = $207,493. Interest saved vs 30-yr = $259,741.
15-year saves $259,741 vs 30-year | 20-year saves $178,528
Try this example →

❓ Frequently Asked Questions

How do I compare two mortgage offers to find the better one?+
Enter the loan amount, interest rate, and term for each offer in the Loan Compare tab. The calculator displays monthly payment, total interest, total paid, and remaining balance at year 5, 10, 15, and 20 for both options. The verdict box shows which option saves more over the full loan life and the total dollar difference. For short holding periods, compare the balance at the year closest to your expected sale date rather than the 30-year total.
Is a lower interest rate always the better mortgage offer?+
Not always. A lower rate on a longer term can cost more in total interest than a slightly higher rate on a shorter term. Closing costs, origination fees, and points can also offset a rate advantage. This calculator compares total paid (principal plus interest) to give you the real picture. Add origination fees to the loan amount in each field to convert the comparison to a true all-in financing cost analysis.
How much more does a 30-year mortgage cost than a 15-year mortgage?+
On a $350,000 loan at 6.75%, the 30-year mortgage costs about $467,000 in total interest versus roughly $207,000 for the 15-year mortgage, a difference of approximately $260,000. The 15-year monthly payment is about $826 higher. Use the Term Compare tab on this calculator to see exact figures for any loan amount and rate. The dollar savings from the 15-year option often surprise first-time homebuyers who focus primarily on the monthly payment.
When should I choose a 20-year mortgage instead of 30 years?+
Choose a 20-year mortgage when the 15-year monthly payment exceeds your comfortable budget but you still want to save significantly on interest. On a $350,000 loan at 6.75%, the 20-year payment is $389 more per month than the 30-year (versus $826 more for the 15-year), while saving roughly $179,000 in total interest. The 20-year is the best middle-ground when cash flow matters but you want to avoid paying the maximum interest cost of a 30-year loan.
Should I include closing costs in the loan comparison?+
Yes, if you are rolling closing costs into the loan or comparing lenders with different fee structures. Adding closing costs to the loan amount in each field converts the comparison from rate-only to true cost-of-financing. If Lender A charges $3,000 in fees and Lender B charges $8,000, enter $403,000 versus $408,000 on a $400,000 loan to see the real total cost difference. This approach often reveals that a slightly higher rate with low fees beats a lower rate with high fees.
How does the balance milestone feature help me compare mortgages?+
The balance at year 5, 10, 15, and 20 shows how much equity each option builds at key decision points. If you expect to sell in 8 years, the year-10 balance is more relevant than the 30-year total cost. A loan with a slightly higher rate but shorter term may show a substantially lower balance at year 10, meaning you capture more equity at sale. This is especially important in a rising home-price market where equity at sale determines net proceeds.
Can I compare a fixed-rate mortgage with an adjustable-rate mortgage?+
For the initial ARM fixed period, enter the ARM rate and the fixed-period length as the term. This compares the ARM cost during the initial period against a fixed-rate alternative for the same duration. This approach cannot model the adjustable portion after the initial ARM period. For full ARM analysis including adjustment caps, floors, and projected payments after the reset, use the ARM Mortgage Calculator on this site.
What is the break-even point between a 15-year and 30-year mortgage?+
The break-even analysis compares investing the monthly payment difference (say $800/month) at a market return versus paying the lower total interest on the 15-year loan. If you can consistently earn more after taxes on that $800 per month than the mortgage rate, the 30-year wins financially. Most financial planners estimate the required investment return to justify a 30-year over a 15-year at 6 to 8% annually after taxes, which is achievable but not guaranteed. The 15-year is the risk-free choice.
How does a 0.5% rate difference affect total mortgage cost?+
On a $400,000 30-year mortgage, a 0.5% rate difference changes monthly payment by about $132 and total interest by roughly $47,500. On a $600,000 loan the same difference scales to about $70,000 in lifetime interest. Use this calculator with both rates to see the exact impact for your specific loan amount. Small rate differences become large dollar amounts on big loans over long terms, which is why shopping multiple lenders for even 0.25% is worth the effort.
What if one mortgage has a different loan amount because of a larger down payment?+
Enter each scenario's loan amount directly. To compare a 10% down payment versus a 20% down payment on a $500,000 home, enter $450,000 (10% down) as Option A and $400,000 (20% down) as Option B. The total cost comparison will include the difference in principal as well as interest, showing you the true all-in cost of each down payment strategy. Note that the 10% scenario may also carry PMI, which you can add to the loan amount as an estimated cost.
Can I use this calculator for home equity loans or second mortgages?+
Yes. The amortization formula is the same for any fixed-rate installment loan. Enter the home equity loan amount, rate, and term to compare two HELOC or home equity loan offers, or use the Term Compare mode to evaluate 5, 10, or 15-year home equity loan terms. Simply enter the home equity loan amount and set the term to the options you are considering.
How do I know which mortgage term is right for my situation?+
Use the Term Compare tab and apply a simple budget test: if you can comfortably afford the 15-year payment without reducing emergency savings or retirement contributions, choose 15 years. If the 15-year payment is too high but the 20-year is manageable, choose 20 years. Reserve the 30-year for situations where monthly cash flow flexibility is essential, such as variable income, planned large expenses in the near term, or when you plan to sell within 7 to 10 years and total cost over the full term is less relevant.
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How do I compare two mortgage offers side by side?

Enter the loan amount, interest rate, and term for each offer in the Loan Compare tab. The calculator instantly shows monthly payment, total interest, total paid, and remaining balance at multiple year milestones for both options. The winner summary at the top shows which offer has the lower total cost and the total lifetime difference between the two.

Is a lower interest rate always the better mortgage?

Not necessarily. A 0.25% lower rate on a 30-year mortgage saves less total interest than the same rate on a 20-year mortgage. A lower rate can also be offset by higher origination fees or points. This calculator compares total paid over the full loan life, which accounts for the combined effect of rate, term, and loan amount. Add origination fees to the loan amount to make the comparison a true all-in cost analysis.

How much more does a 30-year mortgage cost than a 15-year mortgage?

On a $350,000 loan at 6.75%, a 30-year mortgage costs roughly $467,000 in total interest versus about $207,000 for a 15-year mortgage, a difference of approximately $260,000. The 15-year monthly payment is roughly $826 higher. Use the Term Comparison tab to see the exact figures for your loan amount and rate.

When should I choose a 20-year mortgage over a 30-year mortgage?

A 20-year mortgage makes sense when you want significantly lower total interest cost but cannot afford the higher 15-year payment. On a $350,000 loan at 6.75%, the 20-year payment is about $390 more per month than the 30-year payment, while saving roughly $180,000 in total interest. If the 15-year payment ($826 more per month) is unaffordable, the 20-year is a strong middle-ground.

What is the difference between comparing two loan offers versus comparing terms?

Loan Compare mode is for comparing two specific mortgage proposals: different loan amounts, rates, or terms from different lenders or for different properties. Term Comparison mode is for a single loan amount and rate, showing how the 15, 20, and 30-year terms compare. Use Loan Compare when choosing between two lender offers, and Term Compare when deciding how aggressively to pay down a single loan.

Should I include closing costs in the loan amount when comparing mortgages?

Yes, if you plan to roll closing costs into the loan (as many borrowers do) or if you want to compare the true total cost of financing. Adding closing costs to the loan amount in each field converts the comparison from rate-only to total cost-of-financing. If closing costs differ significantly between two offers, including them often changes which offer appears cheaper.

How does the balance milestone feature help me compare mortgages?

The balance at year 5, 10, 15, and 20 shows how much of the loan each option has paid down at key decision points. If you plan to sell in 8 years, the year-10 balance is more relevant than the 30-year total cost. A loan with a higher rate but shorter term may show a much lower balance at year 10, meaning you have more equity to capture at sale.

Can I use this to compare fixed vs adjustable rate mortgages?

For ARMs, enter the fixed-period rate as the rate and the fixed-period length as the term. This lets you compare the initial ARM cost against a comparable fixed-rate period. However, this approach cannot model the adjustable portion after the initial period. For full ARM analysis, the ARM Mortgage Calculator handles adjustment caps, floors, and remaining term projections.

How much does a 0.5% rate difference affect total mortgage cost?

On a $400,000 30-year mortgage, a 0.5% rate difference (say 6.5% versus 7.0%) changes the monthly payment by about $132 and the total interest by roughly $47,500. On a $600,000 loan the difference scales to about $71,000 in lifetime interest. Small rate differences compound significantly over 30 years, which is why even a 0.25% improvement on a large loan is worth pursuing.

What if one mortgage has a shorter term and a higher monthly payment?

Compare total paid (principal plus interest) rather than monthly payment to decide. A shorter-term mortgage always costs less in total interest even though the monthly payment is higher. The relevant question is whether the monthly payment increase is affordable within your budget. The Term Comparison mode shows exactly how much more per month each shorter term requires versus the 30-year baseline.

Can I compare mortgages for different home prices or loan amounts?

Yes. The Loan Compare tab accepts different loan amounts for Option A and Option B. This is useful when comparing a scenario with a 10% down payment against one with a 20% down payment on the same home (different loan amounts, same property) or comparing two different properties entirely. The total paid row immediately shows the lifetime cost difference between the two scenarios.

How do I know which mortgage term is right for my financial situation?

Use the Term Comparison tab to see the monthly payment and total cost for all three standard terms at your specific rate and loan amount. Then apply a simple rule: if you can afford the 15-year payment without straining your budget (meaning it leaves adequate emergency savings and retirement contributions), the 15-year saves the most interest. If the 15-year payment is too high but the 20-year is manageable, choose the 20-year. Reserve the 30-year for situations where cash flow flexibility is essential.

📌 Quick Tips

💡Total paid (principal plus interest) is the definitive measure of which mortgage costs more. A lower rate with a longer term often costs more in total than a higher rate with a shorter term.
💡The balance milestone rows in the comparison table show how quickly you build equity in each option. If you plan to sell in 7 to 10 years, the balance at year 7 or 10 is more relevant than the 30-year total cost.
💡When comparing two offers from different lenders, include origination fees and closing costs by adding them to the loan amount in each field. This converts the comparison from rate-only to true cost-of-financing.
💡In the Term Comparison mode, the extra monthly payment for a 15-year versus a 30-year loan is your required commitment. If the extra amount would strain your monthly budget, the 20-year term offers a middle ground with significant interest savings.
💡A lower monthly payment is not always better. If the 30-year payment is $400 lower than a 20-year payment, but the 30-year costs $180,000 more in total interest, you would need to invest that $400 monthly difference at above 7% to break even on the 30-year choice.