Flat Interest Calculator

Calculate interest charges with ease using our Flat Interest Rate Calculator.

Loan Amount




Rate of Interest (P.A)




Time period





Total Interest


Amount in 1 Months




Whether you are considering applying for a personal loan or are planning your repayments, a flat interest rate calculator can be of use. To know how it works and what it can do for you, read on.

About the flat interest rate calculator

The flat interest rate calculator above is an online tool to help calculate the interest amount due on personal loans. It enhances the ease and efficiency of such calculations and facilitates the comparison of the amount payable under a flat interest rate structure to that due under the reducing interest rate structure. In doing this, it enables informed decision-making.


The Lemonn calculator also helps you estimate your EMIs payable.


But what are flat interest rates and reducing interest rates? There are two types of interest rates that apply to personal loans. When opting for a personal loan you will have to choose between them. The section below will help you understand what flat interest rates are and how they work compared to reducing interest rates.

What is flat interest rate?

In flat interest rate, the rate of interest remains unchanged throughout the loan tenure. That means, the interest is calculated on the total principal amount, and the interest rate and the payable amount for every month remains constant. This is because the principal amount considered does not diminish gradually on repayment.


One may perhaps understand flat interest rate better by comparing it to reducing interest rate. In the latter, the interest is calculated on the outstanding loan amount. So, the interest rate calculated does not pertain to the total principal amount but the principal amount remaining after the repayment of every EMI. Hence, the interest rate applicable reduces as the repayment progresses.


Most borrowers who prefer fixed EMIs and simpler calculations opt for flat interest rates.

How does the flat interest EMI calculator work?

The flat interest rate calculator is an intuitive tool. All you need to use it is the following information.

  • Loan amount: This is the exact amount borrowed. It is necessary for computing the payable interest and the loan EMI.
  • Rate of interest per annum: This is the annual rate of interest at which the loan is being offered to you.
  • Loan tenure: The duration of the loan can either be in months or years. The calculator requests you for the tenure in years, so do the conversion if necessary.


Working the calculator is simply a matter of keying in these variables as prompted. The calculator will use them to assess your monthly EMI amount, the total interest payable during the tenure and the total outgoing amount.

Formula to calculate flat interest rate

In case you are curious or want to simply exercise your brain muscles, here are the formulas you can use to do the math manually.

The formula for flat rate interest calculation is as follows.


Total Interest = (P * R * T)/100


In this equation:

P = Principal amount

R = Rate of interest

T = Tenure in years


By adding the principal amount with the total interest amount you will get the total outgoing amount during the entire loan tenure.

To calculate your monthly EMIs, use the formula below.

Monthly EMI = ( P + (P *R* T)/100) / T*12  

Benefits of using the flat interest rate calculator

A flat interest rate calculator can be really handy if you are applying for a personal loan. Below are some of the benefits of using a flat interest rate calculator like the one above.


  • Accurate loan repayment calculation

Calculating the flat interest rate loan EMI and the total interest is a tedious process. Chances of human error creeping in is high due to this. Not so with the calculator above, which gives you the most accurate numbers possible.


  • Financial planning

Loan EMI repayment is a long term commitment. And it plays an important role in your financial plans as it impacts your monthly budget. That’s why getting the numbers right is crucial for your financial planning. A flat interest rate loan EMI calculator will help get you those numbers with ease.


  • Time-saving

Calculating the flat interest rate EMI amount manually—whether it is by using a pen and a paper or a spreadsheet—is time consuming. Our flat interest rate calculator, on the other hand, does the math for you at the click of a button.


  • Expense management on a monthly basis

Your flat interest rate loan EMIs will be payable every month. EMI payment is not optional. It thus needs to be budgeted in your monthly expenditure. That’s where the calculator can help.


When availing a personal loan, you can either opt for a flat interest rate loan or a reducing interest rate loan. In the article above, we focused on the former, explaining how you can calculate the loan EMI amount and the total interest payable amount with our calculator.


1.What is the advantage of a flat rate?

The main advantage is that the monthly payment at a flat rate does not change with time. This makes it easier to plan and manage expenses on a monthly basis.

2.What is the EMI formula for the flat rate method?

The EMI formula for the flat rate method is: EMI = (Principal + Interest) / Number of Months. Interest is calculated on the entire principal amount throughout the loan tenure.

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