Accumulated Interest Calculator

Formatting only. This does not change the calculation.
The lump sum already invested or deposited today. Use 0 if you are starting from nothing.
Banks advertise an APY, lenders a nominal rate. Say which one you typed in the field below.
Choosing APY converts the quoted yield back to the nominal rate its compounding schedule implies, so a full year returns exactly the APY you typed.
Used only to restate the final balance in today's purchasing power.
Applied to the interest earned to show an after-tax balance. Use 0 for a tax-sheltered account.
Compound interest earned
6,288.95
Compound Interest Calculator
Future value
16,288.95
Total you put in
10,000.00
Of which contributions
0.00
Effective annual yield (APY)
5.0000 %
Equivalent nominal annual rate
5.000000 %
Multiple of what you put in
1.6289
Balance after tax on interest
16,288.95
Future value in today's money
16,288.95
Years for the balance to double
14.21
Average interest a year
628.89
Average interest a month
52.41
Worked out from Compound interest formula A = P(1 + r/n)^(nt), and the future value of an annuity FV = PMT[((1+i)^N - 1)/i] and 3 other sources.

How this is worked out

6 steps
  1. Rate per compounding period = 5% / 1 compounding annually (1 a year).
  2. Effective annual yield = (1 + r/n)^n - 1 = 5%.
  3. No recurring contributions, so the balance grows from the 10000 starting amount alone.
  4. Future value after 10 years = 16288.95, of which 6288.95 is compound interest on 10000 paid in.
  5. Interest accumulated = ending balance - everything paid in = 16288.95 - 10000 = 6288.95.
  6. At this yield the balance doubles every ln(2)/ln(1+i) = 14.21 years.
Year-by-year balancetable
yearcontributionsinterestbalance
1050010,500
2052511,025
30551.2511,576.25
40578.8112,155.06
50607.7512,762.82
60638.1413,400.96
70670.0514,071
80703.5514,774.55
90738.7315,513.28
100775.6616,288.95

Results are general information, not financial, tax, legal, medical or engineering advice.