Loan Comparison Calculator

Compare monthly payment, total interest, and total repayment for a standard fixed-rate loan. Adjust the amount, rate, or term to see how the numbers change. This page also keeps the formula, examples, FAQs, and references close by so you can check the result with confidence.

What This Loan Comparison Calculator Helps You Do

Monthly payment = loan amount x monthly rate / [1 - (1 + monthly rate)^-n]. Review the formula and examples below if you want to see how the result is derived.

This page is meant to give you a fast answer, but it also helps you double-check the math before you make a decision. Start with the inputs that you already know, run the calculation, and then compare the output with the formula, examples, and FAQs below so you can see whether the answer fits the situation you are modeling.

If the result looks off, the usual causes are a unit mismatch, a missing decimal, the wrong scenario, or a value that needs to be entered as a rate instead of a total. The notes on this page are designed to make those checks easy without forcing you to leave the calculator and search for context elsewhere.

  • Use the calculator first for a quick estimate.
  • Use the formula to understand how the result is built.
  • Use the examples to compare common use cases.
  • Use the references when the answer depends on a standard or assumption.

Common Checks

A quick result is useful, but the best result is one that still makes sense when you look at it a second time. If you are comparing scenarios, try changing one input at a time so you can see which variable has the biggest impact on the final answer. That makes it much easier to spot whether the calculation matches your expectations.

It also helps to keep the context of the problem in mind. A calculator can tell you the math, but you still need to decide whether the input represents a total, a rate, an average, or a category-specific assumption. When in doubt, start with a simple example from the page and scale up from there.

  • Check that every unit matches the rest of the problem.
  • Keep rates, totals, and averages separate.
  • Adjust one variable at a time when testing scenarios.
  • Use the smallest realistic input first, then scale upward.

Scenario Planning

This calculator is especially useful when you want a quick answer before you commit time, money, or effort. Try one baseline input set, then change a single number and compare the result so you can see how sensitive the answer is to that variable.

That makes the page useful for more than just arithmetic. It becomes a small decision aid that helps you compare options, test assumptions, and explain the final number with confidence when you need to share it with someone else.

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Result

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Quick Answer: Monthly payment = loan amount x monthly rate / [1 - (1 + monthly rate)^-n]. Review the formula and examples below if you want to see how the result is derived.

How to Calculate Loan Comparison Calculator

  1. Enter the loan amount: Use the amount you want to borrow.
  2. Set the rate and term: The annual rate is converted to a monthly rate in the formula.
  3. Compare the outputs: Review monthly payment, total repayment, and total interest.

Loan Comparison Calculator Formula

Monthly payment = loan amount x monthly rate / [1 - (1 + monthly rate)^-n]
Variable Meaning Unit
Loan amount Principal borrowed $
r Monthly interest rate
n Total number of payments months

Worked Examples

USA - 30-year loan
  • Loan amount: $300,000
  • Annual interest rate: 6%
  • Loan term: 30 years

Result: Monthly payment is about $1,799

A longer term lowers the monthly payment but increases total interest.

UK - Shorter term
  • Loan amount: $200,000
  • Annual interest rate: 5%
  • Loan term: 15 years

Result: Monthly payment is about $1,581

Shorter loans usually cost less in total interest.

How to Interpret Your Results

Range Meaning Action
Lower payment The term is longer or the rate is lower Check total interest before choosing the offer.
Higher payment The term is shorter or the rate is higher Try a longer term or a smaller principal.

Frequently Asked Questions

Yes. Change the amount, rate, or term to compare offers side by side.

No. It focuses on principal and interest only.

The payment is simply the loan amount divided by the total number of payments.
Planning note: This is a simplified fixed-rate loan comparison and does not include lender fees or variable-rate changes.

References

Last reviewed: March 2026