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Lump Sum Compound Interest Calculator
A lump sum is a single deposit that you leave alone to grow. There are no monthly additions. The only thing that changes the balance is the interest it earns on itself.
The starting figures are $15,000 over 22 years at 5.5 percent. Replace them with your own amount and time.
How the growth is worked out
With no deposits the math is short. Multiply $15,000 by one plus the monthly rate of 0.4583 percent. Repeat that 264 times. The yearly return of 5.5 percent is spread across twelve months so each month earns a twelfth of it.
Worked example
Over 22 years at 5.5 percent, $15,000 becomes $50,163. That is 3.34 times the amount you started with.
Halfway through, at 11 years, the balance is $27,431. The second half of the time adds $22,733, which is more than the first half added.
Questions about this calculator
What is $50,163 worth after prices rise 2.5 percent a year?
If prices rise at 2.5 percent a year for 22 years the final balance has the buying power of about $29,138 in starting-year money. Enter your own inflation rate in the calculator to test other cases.
What if you added $100 a month to $15,000 over 22 years?
The balance would reach $101,310 instead of $50,163. The deposits would add $26,400.
What yearly return would double $15,000 in 22 years?
About 3.2 percent a year. That is the rate at which $15,000 reaches $30,000 by year 22.
Is a lump sum of $15,000 better than depositing it monthly over 22 years?
For growth, yes. $15,000 invested at the start reaches $50,163. The same money split into 264 equal monthly deposits reaches only $29,061 at 5.5 percent because most of it spends less time growing. Monthly deposits suit a budget while a lump sum suits cash you already have.
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This page is for education only and is not financial or tax advice.