Loan Comparison Calculator
Compare up to three loans side by side on monthly payment and total interest, and see how much the cheapest saves.
How it's calculated
Two loans can look similar on the monthly payment and cost wildly different amounts overall. The rate, the term, and the amount all pull in different directions. A lower rate saves interest, but a longer term adds it, and a bigger payment can hide a much larger total cost. This calculator runs each loan through the same amortization math so you can see the monthly payment and the total interest side by side.
Take the default, a $300,000 loan compared two ways. Loan A at 6.5 percent over 30 years has a comfortable $1,896.20 monthly payment, but it charges $382,633.47 in interest across its life. Loan B at 6 percent over 15 years has a much higher $2,531.57 payment, yet it costs only $155,682.69 in interest. Loan B costs $635 more a month but saves $226,950.78 in total interest, because the shorter term gives interest far less time to build.
That is the trade at the heart of most loan choices. A longer term buys a lower payment at the price of much more interest, while a shorter term does the reverse. There is no single right answer. The best loan is the one whose payment fits your budget while costing the least total interest you can afford. Enter your own offers, including a third if you have one, to see the real gap between them.
Assumptions
- Each loan is a fully amortized fixed-rate loan compounded monthly, run through the same engine. A loan with a zero amount is skipped.
- The interest difference compares the total interest of the cheapest and priciest of the loans you enter. Fees and points are not included, so add them to the amount if you want to fold them in.
Last updated: 2026-08-08
These assumptions follow our general methodology.
Frequently asked questions
How do I compare two loan offers?
Look past the monthly payment to the total interest over the life of each loan. A lower payment often means a longer term and more interest overall. Enter the amount, rate, and term of each offer here to see both numbers together and the difference between them.
Is a lower monthly payment a better loan?
Not by itself. A lower payment usually comes from a longer term, which can add tens of thousands in interest. The better loan is the one with the lowest total cost whose payment you can still afford, not simply the one with the smallest monthly number.
Does a shorter term always cost less?
In total interest, almost always, because the balance is paid down faster and spends less time accruing interest. The trade is a higher monthly payment. If you can afford it, a shorter term at a similar or lower rate is usually the cheaper choice.
Should I include fees and points in the comparison?
This calculator compares the loans on rate, term, and amount. To fold in origination fees or points, either add them to the loan amount or weigh them separately. Two loans with the same rate but different fees are not truly equal, so it is worth accounting for them.