How to use the interest on irregular deposits and withdrawals
- List each deposit or withdrawal on its own line as a date and an amount, with deposits positive and withdrawals negative. Dates can be 2026-03-15 or 3/15/2026.
- Enter the yearly interest rate and choose how often interest compounds: daily, monthly, quarterly or yearly.
- Pick the date you want the balance on. It must be on or after the last transaction.
- Read the balance on that date and the table that shows the interest earned between dates and the balance after each transaction.
Formula
growth factor between two dates = (1 + rate / n) ^ (n x days / 365)
balance after a date = previous balance x growth factor + deposit or withdrawal
interest earned = ending balance - deposits + withdrawals
Here n is the number of compounding periods in a year: 365, 12, 4 or 1. Because the exponent uses the real number of days, interest is earned between dates even when they are not at period ends.
Four dated transactions
Deposit $5,000 on January 1, deposit $2,000 on March 15, withdraw $1,500 on June 30 and deposit $800 on September 10, at 4.5 percent compounded daily, and look at the balance on December 31. The balance grows to $7,045.20 just after March 15, falls to $5,638.75 after the withdrawal and reaches $6,489.02 after the last deposit.
On December 31 the balance is $6,579.24. The deposits total $7,800 and the withdrawal $1,500, a net $6,300, so the interest earned is $279.24. A single $1,000 deposit at 5 percent compounded monthly for one year ends at $1,051.16, which matches the closed form 1,000 x (1 + 0.05 / 12)^12.
How the page treats each date
Between two transaction dates the whole balance grows at the same rate, then the new deposit or withdrawal is applied. This makes interest additive: splitting one deposit into two on the same date gives exactly the same answer, and a withdrawal simply stops the withdrawn money from earning from that date on.
The page does not round along the way. Real accounts often post interest on a fixed schedule and round each time, so a statement can differ by a few cents. For an overall yearly return on dated cash flows, use the XIRR Calculator.
When to use something simpler
If you add the same amount every month, the Compound Interest Calculator is quicker. If the money earns interest that does not compound, the Simple Interest Calculator applies. This page is for the in-between case where deposits and withdrawals come on arbitrary dates.
Assumptions and limits
- The interest rate is constant for the whole period and is a yearly rate before compounding.
- Interest between dates uses the exact number of days divided by 365, with no special treatment of leap days.
- The earliest transaction must be a deposit, and no withdrawal may be larger than the balance at that time.
- Up to 500 lines are accepted. Lines on the same date are applied in the order they were typed.
- Taxes and fees are not modeled, and nothing typed here leaves your browser.
Frequently asked questions
Can I enter the transactions in any order?
Yes. The page sorts them by date. Lines with the same date keep the order you typed them in. The earliest one must be a deposit.
Why does my bank show a slightly different balance?
Banks usually post interest on a schedule, round it to the cent each time and may use a different day count. This page keeps full precision and compounds at the frequency you choose, so small differences are expected.
What happens if a withdrawal is more than the balance?
The page names the date and asks you to correct it, because the account cannot go below zero in this model.
Does the compounding choice change the answer a lot?
Not much for ordinary rates. Daily compounding at 5 percent gives a yearly yield of about 5.13 percent and monthly gives 5.12 percent, so the effect shows up in the third decimal of the rate.