Average Daily Balance Calculator
The average daily balance method is how most credit cards charge interest. Enter your balance, APR, and billing cycle to see your average daily balance and the exact interest for the cycle.
The average daily balance method adds up your balance for every day of the billing cycle, divides by the number of days, then charges interest on that average. Enter your balance, APR, and cycle length — and any mid-cycle purchases or payments — to see your average daily balance and the exact interest.
Your average daily balance is —
Average daily balance: —
Interest this cycle: —
Effective daily rate: —
A snapshot, not the whole story
This calculator models one billing cycle that you enter by hand. In real life your balance, purchases, and payments change every month. The Pay Down app reads your actual statements across every card and keeps the interest math current, so you never have to reconstruct a cycle yourself.
Your balance changes every day — the app does the daily math for you
A calculator gives you one cycle. Pay Down connects to your bank and tracks the average daily balance and interest on every card automatically.
- Connects to your bank via Plaid — balances always up to date
- Allocates interest day by day across every purchase and payment
- Tracks your progress and alerts you when due dates approach
Understanding the average daily balance method
What "average daily balance" means
To define average daily balance simply: it is the balance you owe averaged across every single day of your billing cycle. Instead of looking at what you owe on the statement date, the card adds up your balance for each day — day 1, day 2, all the way to the end of the cycle — and divides by the number of days. A purchase early in the month counts toward more days than one near the end, and a payment lowers the balance for all the days that follow. That daily weighting is the whole point of the method.
The daily balance method formula
There are two steps. First, find the average: add each day's balance together and divide by the number of days in the cycle. Second, apply interest: multiply that average by the daily rate (your APR divided by 365) and then by the number of days in the cycle. Written out, the daily balance method formula is: interest = average daily balance × (APR ÷ 365) × days in cycle. That is exactly the calculation this tool runs for you.
How to calculate the average daily balance on a credit card
Start with your balance at the beginning of the cycle. Walk through the cycle day by day: when you make a purchase, the balance goes up from that day forward; when you make a payment, it goes down. Keep a running balance for every day, add them all up, and divide by the number of days. The result is your average daily balance, and the interest charge follows directly from the formula above. Enter your own numbers and any mid-cycle transactions in the calculator to see each step done for you.
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Frequently asked questions
What is the average daily balance method?
The average daily balance method is how most credit cards figure your interest. It records your balance for every day of the billing cycle, adds those daily balances together, and divides by the number of days to get one average. Interest is then charged on that average rather than on your balance on any single day.
How do you calculate the average daily balance on a credit card?
Take your balance on each day of the billing cycle, including how it changes when you make a purchase or a payment, add all of those daily balances together, then divide by the number of days in the cycle. The formula is: average daily balance = sum of each day's balance ÷ number of days in the cycle.
How is daily interest on a credit card calculated?
Under the daily balance method, interest equals your average daily balance times the daily rate times the number of days in the cycle: interest = average daily balance × (APR ÷ 365) × days. The APR is divided by 365 to get the daily rate, and that rate is applied to the average balance across the whole cycle.
Is credit card interest compounded daily?
The average daily balance method itself charges simple interest on the average balance for one cycle, so this calculator does not compound within the cycle. In practice, many issuers do add each day's interest to the balance and compound it daily, which raises the effective cost slightly. For the nuance of daily compounding, see our guide on how credit card interest is calculated.
Why is the daily balance method used?
It weights your balance by how many days you actually carried it. A purchase made early in the cycle counts toward more days than one made late, and a payment lowers the balance for the days that follow. Averaging across every day produces a fairer interest charge than using a single end-of-cycle snapshot.
How is this different from the Pay Down app?
This calculator shows the average daily balance and interest for one billing cycle that you enter by hand. The Pay Down app connects to your real cards, reads your actual statements, and tracks interest and payoff across every card month after month — so you never have to reconstruct a cycle yourself.
