Calculate cash advance withdrawal, total repaid, months to pay off, or implied monthly interest rate from any three entered values.
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Cash Advance Interest Formula
The calculator uses a simple monthly interest model. It treats the interest rate as a percent per month and assumes the same monthly rate applies for the full payoff period.
TR = W * (1 + (I/100) * M)
Rearranged formulas for the missing value:
W = TR / (1 + (I/100) * M)
M = (TR / W - 1) / (I/100)
I = ((TR / W - 1) / M) * 100
- TR = total amount repaid for the cash advance
- W = total cash advance withdrawal amount
- I = implied interest rate, as a percent per month
- M = number of months until the cash advance is paid off
If you enter the withdrawal amount, monthly interest rate, and number of months, the calculator finds the total amount repaid. If you enter the total repaid instead of one of those values, it rearranges the same formula to solve for the missing withdrawal amount, payoff time, or implied monthly interest rate.
Monthly Cash Advance Rate Reference
Cash advance costs are often quoted as APR, but this calculator uses a monthly rate. A rough monthly rate can be found by dividing APR by 12.
| APR | Approx. Monthly Rate | Interest on $1,000 for 1 Month |
|---|---|---|
| 24% | 2.00% | $20.00 |
| 30% | 2.50% | $25.00 |
| 36% | 3.00% | $30.00 |
| 48% | 4.00% | $40.00 |
Example Calculations
Example 1: Find the total amount repaid
You take a $500 cash advance, the monthly interest rate is 3%, and it takes 4 months to pay off.
TR = 500 * (1 + (3/100) * 4)
TR = 500 * 1.12 = 560
The total amount repaid is $560.00.
Example 2: Find the implied monthly interest rate
You withdrew $800 and repaid $920 after 5 months.
I = ((920 / 800 - 1) / 5) * 100
I = 3
The implied interest rate is 3.00% per month.
FAQ
Does this include cash advance fees?
Only if you include those fees in the total repaid amount. The formula shown here calculates interest using the withdrawal amount, total repayment, monthly rate, and time. Many cash advances also have a separate transaction fee, such as a flat fee or a percentage of the advance.
Is cash advance interest usually charged monthly?
Credit cards often calculate interest using a daily rate, but this calculator uses a monthly rate to make the estimate simpler. If you know the APR, divide it by 12 to get an approximate monthly rate. The result is an estimate, not an exact credit card statement calculation.
Why is the cash advance interest higher than a normal purchase?
Cash advances often have a higher APR than purchases, and interest may start immediately with no grace period. That means the cost can grow from the day you take the advance until it is fully paid off.
