Simple Interest — Calculated Per Day, Instantly.
Enter your principal, rate, and number of days to see exactly how much interest accrues — perfect for Fixed Deposits (FDs), Savings Accounts, and Credit Cards.
A daily interest calculator tells you exactly how much interest accrues on a sum of money for each day it sits in a loan, savings account, fixed deposit, or investment. Instead of waiting for your monthly bank statement, you get a clear, day-by-day picture of how interest builds — whether you're a borrower trying to understand costs or a saver watching your money grow.
Most financial institutions calculate interest on a daily basis, even if they only show you the figure monthly. That means the numbers are moving every single day. Our calculator brings those hidden daily movements to the surface.
Simple interest is the most straightforward method. You earn (or owe) interest only on the original principal — the base amount never changes. It's commonly used for short-term personal loans, car loans, and RBI/government bonds.
💡 Formula: Interest = Principal × Rate × Time (in years)
Example: ₹1,00,000 at 8% annual rate for 90 days
Daily interest = ₹21.92 per day
Total interest for 90 days = ₹1,972.60
Here, interest is added to the principal at regular intervals — daily, monthly, or annually — and then that larger amount starts earning interest too. Over time, this creates exponential growth (or exponential debt).
📈 Tip: Savings accounts and Fixed Deposits (FDs) use compound interest. Use our Daily Compound Interest Calculator to track those investments!
Using the daily interest calculator takes less than 30 seconds:
You can find the annual rate of interest mentioned in your loan agreement, Fixed Deposit (FD) certificate, or credit card statement. It is typically expressed as a percentage per annum (p.a.). If you know your principal, total interest paid, and time period, you can find the simple interest rate mathematically using: Rate = (Interest × 100) ÷ (Principal × Time).
To calculate daily compound interest manually, use the formula A = P(1 + r/365)^(365×t), where A is the total maturity amount, P is the principal, r is the annual rate (in decimal), and t is time in years. Because doing this by hand for hundreds of days is complex, our daily interest calculator instantly processes this math for you.
Computing interest compounded daily means taking your annual rate, dividing it by 365 to get the "daily rate", and applying that tiny percentage to your balance every single day. Crucially, each day's interest is added back to your balance, meaning the next day you earn interest on an ever-slightly larger amount.
Compounded daily means that your financial institution calculates your interest at the end of every day and immediately adds it to your principal balance. It ensures your money grows (or your debt increases) far faster than if interest was only calculated monthly or annually.
For a simple daily interest loan, divide your Annual Percentage Rate (APR) by 365 to get your daily interest rate. Multiply that daily rate by your outstanding loan balance. The result is exactly how much that loan costs you in interest for that single day.
To convert a simple daily interest rate to an annual rate, multiply the daily percentage by 365. For example, if your daily rate is 0.05%, your annual rate is 0.05% × 365 = 18.25% p.a. If the interest is compounding daily, use the effective annual yield formula: Effective Annual Rate = (1 + Daily Rate)^365 − 1.